vat lieu polyme blend p2 4054

7/25/2019 Vat Lieu Polyme Blend p2 4054

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Chng III

CC PHNG PHP CHTO VT LIUPOLYME BLEND

Hin nay, trn thgii v Vit Nam, polyme blend chyu cchto bng cc phng php sau [1-5]:

- Chto polyme blend tdung dch polyme.

- Chto polyme blend trng thi nng chy.

- Phng php lu ho ng.

- Trng hp monome trong mt polyme khc.

- To cc mng li an xen ca cc polyme.

- Ngoi ra, cn c mt sphng php khc chto polymeblend.

Trong , cc phng php ch to polyme blend trong dungdch, trng thi nng chy trn cc thit bgia cng cht do, luho ng v to cc mng li an xen ca cc polyme c sdng phbin hn c.

III.1. Chto polyme blend tdung dch polyme

Phng php ch to polyme blend bng cch trn v ha tan ccpolyme trong mt dung mi (dung dch cc polyme) hoc trn dung

dch ca mt polyme ny vi dung dch ca mt polyme khc clch slu i v c ng dng trong cng nghip sn xutcc vt liu c hnh thi cc pha ng lin tc, trong c cc mngthm thu xp dng lc v ng dng trong ngnh thgic. Tronghny, cc pha polyme ng lin tc, xen knhau hoc chtn timt pha sau khi pha thhai c trch ly bng dung mi thch hp.to cc mng thm thu xp, polyme thnht c ho tan vo


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mt dung mi ho tan tt, sau dung dch polyme ny c trnvi polyme th hai khng c dung mi. Cui cng, dung dch 2polyme c khun, sau loi bdung mi thu c mngc kch thc pha phn tn micromet [6]. Quy trnh ny cng dng cng nghip trong mt thi gian di sn xut cc mngthm thu tpolyolefin, PA v polyme cha flo.

ch to polyme blend ho trn, tng hp hon ton hocmt phn, mt i hi rt quan trng l cc polyme phi cng tantt trong mt dung mi hoc tan tt trong cc dung mi c khnngtrn ln tt vi nhau. Di y l mt spolyme blend c chtot cc dung mi chung: EPDM-g-MMA/SAN trong dung micloroform [7], PS/PMMA trong dung mi cloroform [8], PB/PPtrong dung mi xylen [9], poly(4-hydroxystyren)/poly(etylen oxit)trong cc dung mi axeton, cloroform, izopropyl axetat, n-butanolv xyclohexanon [10]. u tin, tin hnh ho tan tng polymethnh phn trong dung mi chung thu c cc dung dchpolyme ng nht. Sau , trn cc dung dch polyme theo tltnh ton sn. cc polyme trong dung dch phn tn tt vo nhau,cn phi khuy chng tc khuy cao trong mt thi gian khdi. Trong nhiu trng hp, ngi ta thng ho tan v trn lncc polyme c gia nhit, khi chng strn ln vi nhau tt hn.Phng php ny kh thch hp chto polyme blend dng lm

sn, lp ph, keo dn Tuy nhin, cn lu l loi dung mi, giihn nng ca tng polyme trong polyme blend, nhit trnl cc yu tnh hng mnh ti kh nng trn hp v tnh chtca polyme blend.

Sau khi to mng t dung dch polyme blend bng phngphp phun, qut cn phi ui ht dung mi bng phng phpsy. mng polyme blend ng nht, khng b rn nt b mt,khng bphn hunhit hay phn huoxy ho nhit, nn sy mngtrong thit bsy di p sut thp v nhit thp.

Y. Agari v cng s chto polyme blend PVC/PMMA ccu trc chn lc bng phng php ho tan - khuch tn. u tin,PVC c ho tan trong 2-butanol, sau to mng tdung dchPVC. PMMA c ho tan trong tetrahydrofuran v dung dchPMMA c rt ln mng PVC nhit phng. Khi lng PVCtng ng vi khi lng PMMA. PVC bho tan v khuch tnvo dung dch PMMA v c gi cho ti khi ton b dung mi


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Chng III. CC PHNG PHP CHTO VT LIU POLYME BLEND 125

bc hi. Mng polyme blend PVC/PMMA thu c c mt sdngcu trc gradient theo thnh phn ca 2 polyme [11].

Nhtrn cp, phng php chto polyme blend tdungdch cc polyme c nhc im l phi s dng dung mi nnkhng kinh t, dgy nhim mi trng, hn chkhnng ngdng thc tin.

III.2. Chto polyme blend trng thi nng chy

Khc vi phng php ch to polyme blend trong dung dch vphng php trn hp cc latex polyme, phng php ch topolyme blend trng thi nng chy trn cc thit bgia cng nha

nhit do v chbin cao su nhmy trn, my n trc vt xon,my p, my c phun, my cn... l phng php kt hp ngthi cc yu tc- nhit, c- ho v tc ng cng bc ln ccpolyme thnh phn, cc cht ph gia, trn ln chng vi nhau(blend ho cc polyme). Cc cht phgia trong polyme blend c thl cht tng hp, cht hot ng b mt, cht lin kt (couplingagent), hp cht thp phn tc khnng phn ng, cht ha do,cht khu mch... Trong cng nghchto polyme blend, trn, nv c phun cc polyme trng thi nng chy l cc cng nghph bin nht. V c bn, s pht trin hnh thi cu trc capolyme blend ch to trong my trn ni l hm ca thi gian vtrong my n trc vt xon l hm ca chiu di trc vt xon.

S. Al. Malaika v cng s ch to cc polyme blendPET/EPR, PET/EPR-g-GMA bng qu trnh trn phn ng trnthit btrn ni. u tin, cc mu cao su EPR, EPR-g-GMA ctrn sbvi PET. Sau , hn hp cao su - nha c trn tiptrn thit b trn ni 275oC, tc roto 65 vng/pht trong 10pht trc khi p mu v lm ngui. M men xon ca hn hp caosu - nha trong qu trnh trn nng chy trong my trn ni l hmca thi gian trn cao su - nha [12].

Polyme blend PVC/NBR v PVC/NBR/SBR vi cc tlthnhphn khc nhau c trn trn thit btrn ni 150oC, tc roto30 vng/pht trong 22 pht. Khi lng ca cc polyme thnh phnv cc cht phgia (cc cht n nh PVC nhcc stearat km vbari, hlu ho cao su NBR v SBR bao gm cht khu mch - lu


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hunh, cht xc tin - mecaptobenzatiazol v cht hot ho lu ho- oxit km) c iu chnh sao cho th tch hn hp nng chychim 70% thtch bung trn [13].

S dng my n trc vt xon blend ho cc polyme trng thi nng chy c cc u im sau:

- Qu trnh chto lin tc vi cc polyme, cc cht phn ng dng rn, dng bt v i khi dng lng.

- Trn phn bv trn phn tn rt tt cho cc cht c nhtcao.

- D dng iu khin nhit , p sut v thi gian lu capolyme.

- Khng yu cu sdng dung mi do cc qu trnh xy ra pha rn v pha nng chy nn rt kinh t v thn thin vi mitrng.

- Khng c i hi c bit trc khi gia cng nh cc phnng ghp to cc nhm chc trong polyme ban u.

- C thloi bcc monome cn li (monome khng tham giaphn ng) v cc sn phm phkhi cc polyme.

- C ththc hin qu trnh tlm sch khi sdng my n 2

trc vt xon (trc vt kp) khp hon ton v my n trc vt nchuyn ng qua li (reciprocating single screw extruder).

- Cc qu trnh lin tip nhau t cc phn ng ho hc, trn,thot hi n ct ht v to hnh.

- C thchto cc loi polyme blend khc nhau trn mt dychuyn n gin.

My n trc vt xon gm 2 loi: mt trc vt xon (trc vtn) v my n 2 trc vt xon. My n mt trc vt xon c

sdng chyu trong cng nghgia cng nha nhit do nhcngnghc, cng ngh thi mng, cng nghn ng v cng nghc phun. My n 2 trc vt xon chyu dng trn hp ccpolyme, iu khin hnh thi cu trc ca polyme blend hay vi hpho cc polyme (polymer alloy) cng nh tin hnh cc phn ngtrng hp nh cc phn ng ghp monome ln mch polyme [4].Cn cvo mc n khp v chiu quay ca 2 trc vt xon, my


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n 2 trc vt xon c chia thnh 6 loi khc nhau (hnh III.1). l loi 2 trc vt xon quay cng chiu (co-rotating), loi 2 trcvt xon quay ngc chiu (counter-rotating), mi loi trn c loi 2

trc vt xon khng khp (non-intermeshing), khp mt phn(partly-intermeshing) v khp hon ton (closely-intermeshing) (ttrn xung di hnh III.1) .

Quay cng chiu Quay ngc chiu

Hnh III.1. Mt smy n my n 2 trc vt xon [4].

Hnh III.2 l mt sphn ttrn v y cu to nn cc trc vtxon c vai tr khc nhau.


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Hnh III.2. Mt sphn ttrn v y ca cc loi trc vt xon [4].

Bng III.1 so snh tnh nng ca cc loi my n 2 trc vtxon. Ph thuc vo mc ch, cng ngh ch to v yu cu snphm la chn my n 2 trc vt xon thch hp.

Bng III.1. So snh tnh nng ca cc loi my n2 trc vt xon [4].

Tnh nng Quaycngchiu,tc thp

Quaycngchiu,tc

cao

Quayngcchiu,tc thp

Quayngcchiu,tc

cao

Quayngcchiu,tipxc

Nng sut + ++ + + ++

Trn - phn b + ++ + + ++

Trn - phn tn * + * ++ -

Thot kh * + + ++ +

Nng chy + + + ++ +


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Vn chuyn + * ++ + -

Tlm sch + ++ + * -

Tc trc vt - ++ * + ++Brng RTD + * ++ + *

Tng p + * ++ + -

Tch trc vt - + * * +

Cng sut npliu

+ * ++ ++ +

(RTD: hm phn bthi gian lu, ++ rt tt, * va phi, - km)

Cc my n 2 trc vt xon quay cng chiu khp nhau(intermeshed co-rotating twin screw extruders) c s dng phbin trong cng nghip cht do do kh nng trn c th thay itrn di rng cng nhhiu ng tlm sch v khnng vn hnhddng. quy m phng th nghim, ng knh trc vt xon nh,thng vo khong 25-30mm. quy m bn sn xut v ch th,ng knh trc vt xon vo khong 45-65mm. Trong khi ngknh trc vt xon vo khong 65-150mm hoc thm ch ln hn

150mm (ln nht 400mm) c sdng trong cng nghip.Polyme blend trn csPP (polyme trvmt ho hc) v cc

polyme c nhm phn ng nh PA, PBT... c mt cc vinylmonome cha cc nhm chc nh MA, AA, GMA cng nhcomonome styren (c tc dng tng hiu sut ghp vinyl monome,gim qu trnh khu mch polyme) v peoxit c chto trnmy n mt trc vt xon v 2 trc vt xon trng thi nng chy[14-16]. H. X. Huang v cng s chto polyme blend PP/PA6c mt cht tng hp PP-g-MA (t l thnh phn 80/12/3) trn

my n mt trc vt xon c ng knh 45mm v t l chiudi/ng knh (L/D) 30/1. Xy lanh ca my n c 5 vng, tnh tphu np liu, cc vng c chiu di ln lt l: vng tphu npliu n vtr 1#(13,5D), vng vtr 1#n vtr 2#(3,8D), vng vtr 2#n vtr 3#(4,5D), vng vtr 3#n vtr 4#(4D) v vng vtr 4#n vtr 5#(4,2 D) (hnh III.3).


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Hnh III.3. nh hin vi in tqut in hnh ca cc mupolyme blend PP/PA6/PP-g-MA ti 5 vtr trn my n mt

trc vt xon [17].

Qu trnh ch to polyme blend PP/PA6/PP-g-MA c tinhnh nhsau: sy PA6 80oC trong 10 gi, sau , PA6 cng PP

v PP-g-MA c trn kh ri a vo my n. Nhit ng vi5 vng ca my n (tnh tphu np liu) ln lt l 235-250-250-250-250oC, tc trc vt xon 20 vng/pht, tc np liu vomy n 6kg/gi. Hnh thi cu trc ca polyme blend PP/PA6/PP-g-MA thay i theo vtr ng vi chiu di xy lanh my n. Quanst nh hin vi in t qut in hnh ca cc mu polyme blendPP/PA6/PP-g-MA trn hnh III.3 c ththy tphu np liu n vtr 1#, u tin pha lin tc PP nng chy trong khi pha phn tnPA6 vn cn trng thi rn v polyme blend ti to thnh hn

hp huyn ph. Ti vtr 1

#

, PP nng chy hon ton trong khi PA6tip tc nng chy v bko thnh cc di nha khng ng u vmt sht PA6 c dng hnh cu v elip (trng ging cc git) c to thnh. Ti vtr 2#, cc di nha PA6 bph vto thnhcc ht c kch thc khng ng u (hn hp cc ht c kchthc ln v kch thc nh). T cc v tr 3#n v tr 5#, kchthc pha PA6 gim dn, cc git PA6 nhhn v ng u hn.Ti vtr cui ca qu trnh trn nng chy trn my n mt trc


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vt xon 5#, hnh thi cu trc ca polyme blend PP/PA6/PP-g-MAl p nht [17].

Polyme blend PA6,6/polyme tinh th lng (c tn thng mil Vectra) vi cc tlthnh phn khc nhau c chto trnmy n mt trc vt xon (L/D = 22) c trang bmt chui 12 phnttrn. Nhit cc vng ca my n 290oC, nhit vng trn305oC v nhit ra khi u n 300oC. Tc trc vt 50vng/pht. Nhit trn polyme blend PA6,6/Vectra cao cho phpthc y cc phn ng gia cc nhm chc ca PA6,6 v Vectra. l phn ng ngng tgia nhm amin cui mch ca PA6,6 vinhm cacboxyl cui mch ca Vectra; cc phn ng chuyn veste-amit; cc phn ng axit phn gia nhm cacboxyl v este hoc

nhm cacboxyl v amit... Nhcc phn ng ngng tv chuyn vgia cc nhm chc ca PA6,6 v Vectra to thnh copolymePA6,6-NHCO-Vectra ti chm cc polyme PA6,6 v Vectra tnghp mt phn vi nhau [18].

PA6,6:

-[-NH- CH2- CH2- CH2- CH2- CH2- CH2- NHCO- CH2- CH2-CH2- CH2 CO-]-

J. Li v cng s ch to polyme blend PS/EPDM trn my

n mt trc vt xon c nhit 4 vng tphu np liu n un ln lt l 160, 180, 210 v 210oC vi tc ng ca bc xsium song song vi hng chy ca nha nng chy. Nhbc xsium, copolyme PS-EPDM to thnh (do skt hp cc gc ln caPS v EPDM) tng khnng tng hp mt phn ca polyme blendPS/EPDM [19].


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Cng ngh ch to polyme blend s dng my n 2 trc vtxon c ng dng mt cch hiu qucho cc polyme blend 2thnh phn nh PMMA/PS, PMMA/PU, PC/PS, PS/PE, PS/PP,PC/PP, PA/EVA [20-23] v polyme blend 3 thnh phn nhPA/PS/PP [24]. Trn hnh III.4 m t s trn nng chy 2polyme dc theo my n 2 trc vt xon. Cc qu trnh xy ra trongmy n 2 trc vt xon tng tnh trong my n mt trc vtxon, chkhc l hiu qutrn v phn tn 2 polyme trn my n2 trc vt xon tt hn trn my n mt trc vt xon. Trong giaion u tin, sau khi np liu vo my n 2 trc vt xon, 2polyme trng thi rn. Trong giai on tip theo, hn hp 2polyme nng chy dng huyn ph. Cui cng, trc khi ra khiu n, hn hp 2 polyme nng chy trng thi lng.

Hnh III.4. Sm ttrn qu trnh trn nng chy 2 polymedc theo my n 2 trc vt xon.

Trn hnh III.5 l hthng my n 2 trc vt xon gn vi myto ht sdng chto polyme blend.


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Hnh III.5. Hthng my n 2 trc vt xon gn vi my to ht.

Qu trnh trn hp/blend ho 2 polyme PP/PA6 kh n ginv c cc qu trnh n phn ng hai bc (two-step reactiveextrusion) v n phn ng mt bc (one-step reactive extrusion).Trong qu trnh n phn ng hai bc cc polyme PP/PA6 c MA,styren v peoxit trn my n 2 trc vt xon, u tin chc ho PPvi MA bng phn ng ghp gc tdo ca MA vo mch polyme,

sau xy ra tng hp mt phn PP v PA6 nhc mt PP-g-MAto thnh. Qu trnh ghp gc tdo ca MA vo mch PP xy ra rtmnh mvng nng chy trong my n 2 trc vt. Cc my ntrc vt xon thng c trc vt kh di ghp gc tdo ca vinylmonome vo mch polyme hoc trn hp cc polyme, trong khivng nng chy ch cn chiu di ngn. Nh vy, c th s dngmy n 2 trc vt xon tin hnh ng thi cchc ho ln tng


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hp phn ng polyme blend PP/PA6. Vic iu chnh hnh thi cutrc ca polyme blend theo mun lin quan ti kh nng hotng ho hc ca PA6, MA, styren, peoxit v thi gian lu trongmy n [4]. C nhiu phng n tin hnh trn hp phn ng mtbc nhng phi ch gim ti mc thp nht homopolyme tothnh v monome khng tham gia phn ng v chng sphn ngvi polyme c nhm chc (nhcc nhm amin cui mch ca PA6,PA66... hay cc nhm cacboxyl cui mch ca PA66...). Cc phnng ny s gim nng nhm chc ca polyme c nhm chc,khng thun li cho phn ng gia polyme c nhm chc vipolyme va chc ho.

Hin nay ngi ta c thsdng 3 phng n tin hnh trnhp phn ng mt bc sau:

a, Phng n thnht: tt ccc nguyn liu (PP, PA6, MA,styren v peoxit) c a vo my n ng thi qua phu cpliu chnh. Nhit xi lanh my n (nng my n) c duytr 240oC. Lht gi t gn u n loi bcc cht dbay hi nh cc monome khng tham gia phn ng cn li.Trong phng n ny, qu trnh chc ho PP bi phn ng ghpgc tdo ca MA vo mch ca n dbnhiu bi sc mt caPA. PA d dng phn ng vi polyme ca MA v MA khngtham gia phn ng ghp.

b, Phng n thhai: PP, MA, styren v peoxit c a vomy n qua phu cp liu chnh v PA6 c a vo my nqua phu cp liu khc pha gn u n. Nhit xi lanh myn gia 2 phu cp liu l 200oC v nhit phn cn li ca xilanh my n l 240oC. Lht gi t trc phu cp liu thhaiv gn u n. Trong phng n ny, c 2 qu trnh c lp nitip nhau xy ra theo chiu di my n. Qu trnh chc ho PP biphn ng ghp gc tdo ca MA vo mch ca n khng bnhhng bi PA, khnng phn ng ca PA6 vi polyme ca MA vMA cn li gim i nhiu.

c, Phng n thba chkhc phng n thhai chtin hnhht kh trc khi a PA6 vo my n. iu ny cho php loi bmonome MA khng tham gia phn ng cn li khi PP chc hotrc khi trn hp vi PA6 (xem hnh III.6). Trong phng n ny,phn ng gia PA6 vi MA cn li gim hn na khi a PA6 vo,


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do stng hp gia 2 polyme PP v PA6 tng ln v tnh chtcca vt liu polyme blend tng ln r rt. Chng hn, dn dikhi t ca vt liu polyme blend PP/PA6 (80/20) ch to theo

phng n thba ln hn ng kso vi vt liu c chto theophng n thhai.

Hnh III.6. n phn ng hai bc cc polyme PP/PA6 c mtMA, styren v peoxit trn my n 2 trc vt xon c ht kh

trc phu a PA6 vo [4].

Polyme blend nhit do chng tnh n trn cspolyanilin

(to thnh bi oxy ho anilin vi cht pha tpdodexylbenzensulffonic axit), PS (pha nn) v copolyme ca styrenv butadien (SBS) lm cht tng hp c ch to trn myn 2 trc vt xon quay ngc chiu cc nhit 160, 170, 180,190oC (tnh tphu np liu n u n) vi tc trc vt xon135 vng/pht. Sn phm polyme blend c dng di bng theo uto hnh kch thc 16x1,5mm [25].


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Mt cng nghkh phbin chto polyme blend l ngn cc polyme (coextrusion). Sn phm ca qu trnh ny lpolyme blend nhiu lp/a lp. Cng nghny thch hp cho ccpolyme c tlnht ln ti 40/1 v chnh lch nhit nngchy ca cc polyme ln ti 80oC m khng gy phn hunhitcc polyme thnh phn. Cc polyme nhit do c sdng phbin trong cng nghng n l PE, PP, PA, PS, PVC, ABS,polyeste... [26]. Nguyn tc chung ca cng ngh ny l ccpolyme c nng chy ring rtrong cc my n trc vt, sau chng c chy ng thi vo mt u n to hnh sn phmcui cng. Hnh III.7 l snguyn tc chto polyme blend c 8lp t2 polyme nng chy A, B bng phng php ng n (2 lnkt hp qua u to hnh theo chiu thng ng v chiu ngang).

Sau 11 ln kt hp, c tng s4096 lp trong polyme blend A/B (slp 2n+1 vi n l ln kt hp qua u to hnh) [27].

Hnh III.7. Snguyn tc chto polyme blend c 8 lp t2polyme nng chy A, B bng phng php ng n [27].

Hnh III.8 l s m t qu trnh ng n trc tip 3

polyme. Cu trc ng n ca cc polyme l cu trc nhiu lp vcu trc ny thch hp cho qu trnh to hnh nhit sau ny thu c vt liu c hnh dng mong mun. D. Silagy v cngs tin hnh ng n mt polyme lm lp nn (polymenhit do PVC, ABS, PE, PP, PA, polycacbonat) vpolyvinyliden florua (-CH2-CF2-)n (PVDF) lm lp mt c tcdng bo v. Do lp polyme nn thng rt dy (vi milimt) v


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lp mt PVDF rt mng (vi micromet) nn vt liu polyme blendthu c c cu trc bt i xng [28].

Hnh III.8. Snguyn tc hthng ng n trc tip3 polyme [28].

G. Gururajan v cng s tin hnh ng n - thi mngpolyme blend LDPE/PP t 2 my n vi nhit u nh hnh240oC (trc khi thi mng). Cng nghny rt ph hp chtomng 2 lp PE (lp trong)/PP (lp ngoi). Mng 2 lp LDPE/PP ctrong sut quang hc tt [29]. Tng t, R. Valette v cng s ch to polyme blend 2 lp PE/PS bng cch sdng cc my

n Kaufmann v Haake-Rheocord tng ng cho PE v PS. Haipolyme cng c n t2 my n ti u n c iu khin nhit vi tc chy ca nha khc nhau. Nhit u n tngng vi PE v PS l 200 v 220oC. Sau khi n, mng polymeblend 2 lp PE/PS c ko nhtrong khng kh sang bnc lmlnh bng mt trc ko ngui c thiu chnh tc [30].


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Cc tm polyme blend 3 lp polyeste/tinh bt nhitdo/polyeste c chto bng cch sdng my n 2 trc vtxon cho lp tinh bt nhit do gia v my n mt trc vt xoncho cc lp polyeste 2 bn ngoi [31].

Polyme-blend-poly(3-hydroxybutyrat-co-3 hydroxyvalerat)/poly(-caprolacton) c chto trn my cn 2 trc trng thi nng chy(hnh III.9). Cc trc cn c gia nhit ti 175oC hn chphn hunhit poly(3-hydroxybutyrat-co-3- hydroxyvalerat). u tin, cc htpoly(-caprolacton) c a vo my cn 2 trc, sau l cc htpoly(3-hydroxybutyrat-co-3-hydroxyvalerat). Nh cc ht poly(-caprolacton) nng chy trc, poly(3-hydroxybutyrat-co-3-hydroxyvalerat nng chy sau) do , hn chnng lng gia nhit 2

trc cn v gim hin tng phn hunhit poly(3-hydroxybutyrat-co-3- hydroxyvalerat). Hai polyme c trn nng chy trn my cn 2 trctrong 4 pht, m bo 2 pha phn tn vo nhau tt nht [32].

Hnh III.9. Hthng my cn 2 trc cho cht do v cao sudng chto polyme blend.

Polyme blend EPDM/EP-g-MA (50/50) c 0,5pkl cht chngoxy ho Igranox 1010 c chto trn my cn 2 trc 200oCvi tc quay 25 vng/pht trong 7 pht. Sau khi kt thc qutrnh trn nng chy, polyme blend EPDM/EP-g-MA ging nhcao


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su nhit do c lm ngui xung nhit phng v ct thnh htvi kch thc mong mun [33].

Kt hp nhiu qu trnh cng ngh tc ng n cc polymetrong mt hn hp l gii php c hiu quthu c sn phmpolyme blend c cht lng, ngn nga cc hin tng khng mongmun nhphn hunhit v phn huoxy ho nhit cc polyme.Kt hp qu trnh n, p phun hoc c phun cc polyme c nhngu im sau:

- Gim ti mc thp nht hin tng phn hunhit v phn huoxy ho nhit cc polyme nhp/c v to hnh trc tip.

- Diu chnh hnh thi cu trc ca polyme blend trong qu

trnh trn hp trn my n 2 trc vt xon.- C thng dng chto nhiu loi sn phm khc nhau.

- Gp phn gim gi thnh sn phm.

Trn hnh III.10 m tqu trnh n v p phun/c phun ccpolyme c monome v cc cht phgia h trghp monome vopolyme.

Hnh III.10. Hthng lin hp my n trc vt xon - pphun/c phun cc polyme.

(a: polyme A; b: polyme B; c: monome; d: cc cht phgia htrghpmonome vo polyme A; e: my n trc vt xon; f: khun; g: khoang tch

trnha nng chy; h: my p).


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Snguyn tc lm vic ca hthng my n trc vt xon -p phun/c phun cht do, polyme hoc polyme blend c thhin trn hnh III.11 [34-36]. Nha c nng chy nhtc ng xca trc vt v nhit cung cp cho xy lanh my n. Khi trc vtxon ng thi l pit tng dng chuyn ng vpha sau v nhanng chy c vn chuyn y ti bung phun, pit tng nhanhchng chuyn ng vpha trc v phun nha nng chy qua uphun vo khun to hnh sn phm.

Hnh III.11. Snguyn tc lm vic ca hthng my ntrc vt xon - p phun/c phun cht do [34.

A: phu np liu, B: tht gn khun p, C: bung phun, D: cccun/bphn gia nhit, E: xy lanh my n gia nhit, F: trc vt xon pittng chuyn ng qua li. Hnh trn: pit tng chuyn ng vsau, trc

khi phun cht do. Hnh di: pit tng chuyn ng vpha trc v phuncht do.

D. Jarus v cng s chto polyme blend PP/PA66 c nhiulp bng cch ng n - c phun PP, PP-g-MA (cha 0,5% MA)v PA66 trn 3 my n - c phun cc nhit tng ng l180oC, nhit gia nhit nng chy ca PP v PA66 (220oC)v nhit cao hn nhit nng chy ca PA66. Sau , polyme


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blend PP/PP-g-MA/PA66 (65/10/25) c p khun. Nhkhnngtng hp tt ca PP v PP-g-MA nn gia cc lp PP v PP-g-MAkhng c s khc bit. Trong polyme blend 3 lp PP/PP-g-

MA/PA66, chc lp PA66 tch khi cc lp c PP. Hnh III.12 mtcu trc nhn - v(core-skin) bt ng hng vi cc lp PA66phn tn trong pha lin tc PP. lp v, cc lp PA66 nh hngsong song vi bmt. lp nhn, cc lp PA66 cun li v nhhng vung gc vi hng phun nha [37].

Hnh III.12. M tcu trc cc lp mng p phuntPP/PP-g-MA/PA66 [37].

c phun ng gi ng hc (dynamic packing injectionmolding-DPIM) hn hp polyme l mt phng php hiu quchto polyme blend (c thiu khin c hnh thi cu trc capolyme, c bit l nh hng cc mch i phn tpolyme). S

thit bc phun theo phng php DPIM ch to polymeblend HDPE/PP c thhin trn hnh III.13, trong , mu cp chuyn ng lp li trong bung bng 2 piston chuyn ngngc chiu nhau vi cng mt tn sv qu trnh ho rn xy ra tthnh khun ti li khun. Bng cch ny c th to c mupolyme blend nh hng cao [38, 39]. Quy trnh c th ch topolyme blend HDPE/PP bng phng php DPIM nhsau: u tin


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trn hp polyme blend HDPE/PP trong my n 2 trc vt xon vinhit xi lanh my n 160-190oC. Sau khi ct ht v sy kh,tin hnh c phun polyme blend HDPE/PP vo khun bng myc phun vi nhit xi lanh 190oC v p lc phun 900kg/cm2. Sau, sdng cng nghc phun ng hc ng gi nh nu trn. Cc kt qunghin cu snh hng ca cc polyme trongpolyme blend HDPE/PP bng o siu m v nh hin vi in tqutcho thy khi HDPE l pha lin tc, cc mch HDPE nh hng dctheo hng chy. Tng t, khi PP l pha lin tc, cc mch PPtrong trong cc phin ban u (parent lamella) nh hng dc theohng chy.

Hnh III.13. Shthng c phun ng gi ng hcpolyme blend [38].

1: ming, 2: rnh, 3: piston, 4: ng dn, 5: u ni, 6: mu.

C. Wang v cng s ch to polyme blend PA6/EPDM-g-MA bng phng php DPIM v phng php c phun truynthng. Nhit cc vng trn xy lanh my n 2 trc vt xon vtc trc vt ln lt l 190-220-230-230-230-220oC v 120vng/pht. Cc thng s cng ngh s dng trong phng phpDPIM c thhin bng III.2. Polyme blend PA6/EPDM-g-MA


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(t l80/20) ch to bng phng php DPIM c cc tnh cht cln hn so vi c phun truyn thng. M un n hi ca polymeblend PA6/EPDM-g-MA ch to bng phng php DPIM v c

phun truyn thng ln lt l 1,056 v 0,953 GPa; bn ko tca polyme blend PA6/EPDM-g-MA ch to bng phng phpDPIM v c phun truyn thng ln lt l 31,62 v 28,84 MPa.

Bng III.2. Cc thng scng nghsdng trong phng phpDPIM [38].

Thng scng ngh Gi trthng s

p sut phun (MPa)p sut ng gi (MPa)

Nhit nng chy (oC)

Nhit khun (oC)

p sut ng gi ng hc (MPa)

Tn sng gi ng hc (Hz)

9050

240

20

35

0,3

chto polyme blend c cc tnh cht mong mun, ngi taphi ti u ho cc thng scng ngh(v d, my n - phun p,cc thng sny l thi gian sy, nhit cc vng trn xi lanh camy n, p sut phun, p sut duy tr, thi gian np liu...) v tlcc polyme thnh phn cng nhhm lng cc cht phgia. Khi, hnh thi cu trc pha phn tn trong pha lin tc v cc tnhcht c, l, nhit ca polyme blend c thp ng yu cu sdng.

III.3. Phng php lu ho ng

Bn cnh phng php ng trng hp cc monome hoc trngngng cc monome, cc hp cht thp phn tchto cc chtn hi nhit do (thermoplastic elastomer) nh copolyme khistyren-butadien-styren hay polyuretan nhit do, ngi ta cn chto cc cht n hi nhit do bng cc phng php khc: (a) trnhp khng phn ng mt loi polyme nhit do vi mt loi cao suhoc (b) trn hp c phn ng mt loi polyme nhit do vi mt


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loi cao su. Trong trng hp sau, cc ht cao su c phn tn vphn b vo nn polyme nhit do. S phn tn v phn b cacao su vo nn polyme nhit do cng nhskhu mch chn lcca cao su l cc qu trnh xy ra ng thi trong qu trnh trnnng chy polyme nhit do v cao su. Cht n hi nhit do chto theo phng php ny c xem nhmt loi polyme blendc bit.

Trong polyme blend cao su/nha nhit do, khi cao su bkhumch hon ton, tnh cht ca nha nhit do khng c bo ton,ngi ta khng thgia cng polyme blend ny c na. khcphc cc nhc im trn, ngi ta thng lu ho cao su mt cchc chn lc (lu ho cao su khng hon ton) trong hn hp vipolyme nhit do di tc ng ca nhit cao v trn chc trncc my cn, my trn ni, my n, my p, my p phun... Nhvy, bn cht ca lu ho ng l khu mch c chn lc pha phntn l cao su, ngn nga n khi kt tli vi nhau, kt dnh cc htcao su khu mch bng polyme nhit do.Lu ho ng i hi ccht cao su c kch thc micromet v cc ht cao su phi c khumch mt mc xc nh trong pha polyme nhit do c t lnh hn. Lu ho ng thng c ng dng cho cc polymeblend tcao su (thng dng vi tlln hn) vi mt polyme bnkt tinh nhPE, PP hoc polyme v nh hnh nhPVC. Sau khi

lu ho ng, cc ht cao su khu mch c trn v phn tn trongpolyme nhit do. Pha cao su trthnh pha phn tn trong pha lintc l nha nhit do.

C th tin hnh lu ho ng c chn lc cao su trong qutrnh trn nng chy vi polyme nhit do hoc lu ho ng mtphn cao su trc khi trn nng chy vi polyme nhit do [5]. Khia vo polyme blend mt hoc mt s cht khu mch, nhtca pha cao su tng. Khi mc khu mch pha cao su ln shnchsto thnh kch thc cc ht nhhn, gim din tch bmt

do to thnh cc khi ln v skt tcc ht cao su phn tn vinhau. V th, sphn tn cc pha trong polyme blend cao su/nhanhit do lu ho ng khng ng u. Polyme blend cao su/nhanhit do lu ho ng kt hp c cc tnh cht ca cnha nhitdo v cao su, thng tt hn cao su khu mch bng lu ho tnh.c bit, n c gia cng trn cc thit bgia cng nha nhit do


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nhmy cn, my n trc vt xon, my p phun... v c th tisinh c.

Lu ho ng polyme blend trn c s CSTN vi PP v PEang c squan tm ca nhiu chuyn gia trn thgii [40-43].Vi tc nhn khu mch lu hunh, n c thphn ly trong cao sucha lu ho nhit phng v khnng phn ly ca n tng khitng nhit . Theo M. Hernandez v cng s, trong qu trnh luho ng polyme blend CSTN/PP, skhu mch pha CSTN tng nht ca polyme blend CSTN/PP. Qu trnh lu ho cao su thngc tin hnh nhit cao hn 75oC v nhit 135-150oC,khong 8% lu hunh (so vi khi lng cao su) tham gia phn nglu ho cao su. Ni chung, qu trnh lu ho CSTN xy ra rt phc

tp v thu c cc sn phm lu ho khc nhau. Cu polysunfit nigia cc mch CSTN c th thay i (ph bin t S2 n S6) tuthuc vo iu kin phn ng. Di y l sphn ng lu ho4 mch phn tCSTN bng lu hunh [44]:

C = C

CH

H

CH2-...

CH2

S8

C - CH2- CH

2-...

CH3

S...- CH2...-CH

2-

H - C - CH = CH - CH2-...

CH3

S...- CH2

...-C - C = CH

H CH3

CH2-...

C = C

CH3 H

CH2- CH

2-...CH2

+

(4-6)

(4-6)

135 - 150 oC

+

...-

4

Ngoi khu mch CSTN trong polyme blend CSTN/HDPEbng lu hunh, C. Nakason v cng scn khu mch CSTN bngcc peoxit nhbenzoyl peoxit, dicumyl peoxit (k hiu ROOR) nhit 140-150oC [41]. Qu trnh khu mch CSTN c m tnhsau [44]:


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ROOR 2 RO.

H - C = C

CH3

...-CH CH2-...

ROH - C = C

CH3

...-CH2

CH2-...

...-CH

H - C = C

CH3

...-C CH2-...

H

H - C = C

CH3

...-C CH2-...

H

CH2-...

H - C = C

CH3

ROH+.

.

.2

+

Di y l phn ng khu mch cao su EPM bng cc peoxit:

Cht n hi nhit do tiu biu c thng mi ho lpolyme blend PP/EPDM lu ho ng. Hcht khu mch cao su

lu ho tnh gm lu hunh, cht xc tin (tetrametyl tiuramdisulfit, mecaptobenzatiazol) v cht hot ho lu ho (oxit km) c p dng cho lu ho ng polyme blend PP/EPDM [5, 45].Trnh An Huy v cng s tin hnh lu ho ng polyme blendPP v EPDM vi hcht lu ho gm lu hunh, tetrametyl tiuramdisulfit (TMTD), mecaptobenzatiazol trn my trn ni Haake nhit 180-230oC [46, 47]. Hnh III.14 m ttm tt quy trnh sn


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xut polyme blend PP/EPDM lu ho ng sdng hkhu mchgm lu hunh, cht xc tin (tetrametyl tiuram disulfit,mecaptobenzatiazol) trong my trn ni. Trong qu trnh trn hp,

do nh hng ca lc ma st, nhit thc trong my trn ni stng nhanh v c thdn n sphn hunhit ca polyme blendPP/EPDM. Do , ngi ta thng t nhit ban u trongbung trn 180oC, tc quay r to 50 vng/pht. Nh, ncui qui trnh sn xut, nhit ca khi nha nht (stocktemperature) khng vt qu 230oC.

Hnh III.14. Qu trnh sn xut polyme blend PP/EPDMlu ho ng trong my trn ni [46].

C ch khu mch EPDM bng lu hunh, cht xc tin

(tetrametyl tiuram disulfit, mecaptobenzatiazol) tng tnhkhumch CSTN. Sdng alkylphenol khu mch EPDM shiu quhn rt nhiu nu s dng cht xc tin clorua thic ngm nc(SnCl2.2H2O). Cc phn ng xy ra trong qu trnh khu mchEPDM nhsau:


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Cc phn ng xy ra trong qu trnh lu ho EPDM bngalkylphenol /SnCl2.2H2O [46]

Y. Kim v cng s chto polyme blend PP v EPDM bngcch trn hp v lu ho ng ng thi PP v EPDM (50/50,pkl/pkl) trn my trn ni nhit 190oC. EPDM c lu hobng dicumyl peoxit (DCP) c mt PP v ionome EMA l poly(etylen-co-axit metacrylic) c trung ho bi cc ion kim loi Na+v Zn2+(tlEMA thay i t5 n 20% so vi tng lng PP vEPDM). Hnh thi cu trc ca polyme blend bnh hng bi tlthnh phn 3 pha (pha EPDM lu ho ng, pha PP v pha ionomeEMA) [48]. Ngoi DCP, nha dimetylol phenolic cng c sdng khu mch EPDM trong qu trnh trn v lu ho ng


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ng thi PP v EPDM trng thi nng chy trn my trn ni[49].

Trong bng III.3 l mt sc trng cng nghn - lu hong polyme blend PP/EPDM (64/36) khi nhit xy lanh my nl 193 v 232oC, cc cht khu mch l dimetyloctylphenol v luhunh. Khi n - lu ho ng polyme blend PP/EPDM nhit 193oC, nng sut n polyme blend PP/EPDM s dng cht khumch hphenol nhhn so vi cht khu mch lu hunh. Ngcli, khi n - lu ho ng polyme blend PP/EPDM nhit lnhn (232oC), nng sut n polyme blend PP/EPDM sdng chtkhu mch h phenol ln hn so vi cht khu mch lu hunh.im ni bt ca polyme blend PP/EPDM khu mch bng

dimetyloctylphenol l cao su nhit do thu c rt mm mi (cng khong 35 SoA) v duy tr kh nng gia cng d dng nhnha nhit do [3].

Bng III.3. Mt sc trng cng nghn - lu ho ngpolyme blend PP/EPDM [3].

Nhit xy lanh 193oC Nhit xy lanh232oC

c trng

Khumch hphenol

Khumch lu

hunh

Khumch hphenol

Khumch lu

hunh

Nhit vtn (oC)

197 203 232 234

Tc n(g/pht)

199,5 201,8 182,5 171,2

Trn hnh III.15 l nh hin vi in t truyn qua capolyme blend PP/cao su etylen-propylen (PP/EPR, t l 40/60)ch to bng phng php trn hp c hc (ct bn tri) vphng php lu ho ng (ct bn phi) trn thit bn 2 trcvt xon. Ging nh hnh thi cu trc pha ca polyme blendPP/EPR ch to trn my trn ni, polyme blend PP/EPR chto bng phng php trn hp c hc cc t l chiu


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di/ng knh trc vt (L/D) khc nhau u c hnh thi cutrc pha ng lin tc in hnh. c trng chung vhnh thicu trc pha ca polyme blend PP/EPR khng phn ng hu nhkhng thay i, k csau khi trn hn hp PP/EPR vi cng tng i cao. Pha cao su EPR khng khu mch c th bbin dng do lc x (bi tc ng ca 2 trc vt xon) nhnghnh thi cu trc pha ng lin tc ca polyme blend PP/EPRvn c ginguyn. Khi a vo hhp cht peoxit ng vaitr ca mt tc nhn lu ho chn lc pha cao su EPR, qu trnhlu ho ng gy ra s bin i hnh thi cu trc pha capolyme blend PP/EPR theo chiu di ca my n. R rng l t lL/D bng 10, polyme blend PP/EPR c hnh thi cu trcpha ng lin tc, cc tlL/D bng 16 v 22, hnh thi cu

trc pha ca polyme blend PP/EPR bin i, khng cn nglin tc. Trong giai on cui ca qu trnh chto, tlL/Dbng 40, cc ht cao su EPR c phn tn kh ng u trongpha PP c nht chy tng i nh hn v chim t l nhhn. Thi gian lu cho qu trnh lu ho ng lin tc polymeblend PP/EPR chcn khong 30 giy l xy ra phn ngkhu mch cao su EPR v bin i hnh thi cu trc pha trongpolyme blend PP/EPR.

H. Ismail, Supri v cng s tin hnh lu ho ng

polyme blend trn csPVC vi NBR v PVC ti sinh (PVCr)vi NBR c cc hp cht thp phn tnh glyxidyl metacrylat(GMA) hoc axit acrylic (AA) v cht khi mo DCP [51-53].Trong thnh phn ca cc thp PVC v PVC rc 20% cht hado dioctylphatalat (DOP) (so vi nha), 3% cht n nhstearat catmi/stearat bari (tl1/1) (so vi nha). Hcht khumch cho polyme blend NBR/ PVCrbao gm lu hunh (0,6%so vi cao su NBR), cc cht xc tin TMTD (0,2% so vi caosu NBR), dibenzothiazyl disulfit (0,6% so vi cao su NBR), cccht hot ho lu ho l oxit km (3% so vi cao su NBR) vaxit stearic (1,5% so vi cao su NBR). Vi polyme blendNBR/PVC chdng cht khu mch l DCP (0,2% so vi nhaPVC). Trn bng III.4 l thnh phn ca polyme blendPVCr/NBR/GMA lu ho ng.


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Trn hp chc Lu ho ng

Hnh III.15. nh hin vi in ttruyn qua ca polyme blendPP/EPR (tl40/60) chto bng phng php trn hp chc(ct bn tri) v phng php lu ho ng (ct bn phi) trn

thit bn 2 trc vt xon c tlL/D khc nhau [50].


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Bng III.4. Thnh phn ca polyme blend PVCr/NBR/GMAlu ho ng [52].

Thnh phn polyme blend (pkl)Nguyn vt liuI II III IV V

PVCr 80 60 50 40 20

NBR 20 40 50 60 80

Cht n nh 3 3 3 3 3

Cht ha do 20 20 20 20 20

DCP 0,2 0,2 0,2 0,2 0,2

GMA 4 4 4 4 4

Oxit km 3 3 3 3 3

Axit stearic 1,5 1,5 1,5 1,5 1,5

Dibenzothiazyldisulfit

X X X X X

TMTD X/3 X/3 X/3 X/3 X/3

Lu hunh* X X X X X

X: 0,6% ca cao su NBR

Qu trnh ch to cc polyme blend NBR/PVC v NBR/PVCrc tin hnh trn my trn ni Haake trng thi nng chy. Sauy l quy trnh chi tit chto polyme blend NBR/PVCr: u tinPVCrc trn sbvi cc cht n nh stearat catmi/stearat bari,cht ha do DOP v GMA trong 5 pht nhit phng, sau hn hp trn c a vo my trn ni Haake gia nhit n150oC v trn tip 2 pht vi tc roto 50 vng/pht, tip theo

a NBR vo bung trn. H cc cht hot ho (oxit km - axitstearic) v hcht khu mch (lu hunh, cc cht xc tin) ln ltc a vo hn hp NBR/PVCrsau 6 pht v 7 pht trn trngthi nng chy. Tip tc trn hn hp NBR/PVCr 4 pht trngthi nng chy, khi m men xon ca ht gi trcn bng. Saukhi kt thc trn nng chy, hn hp NBR/PVCr c to tmmng trn cn my cn 2 trc v p trn my p thulc 150oC


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trong 4 pht. Trong qu trnh lu ho ng NBR/PVCr c mtGMA v cc cht khu mch c cc phn ng xy ra nhsau:

- Phn ng gia GMA vi PVCr c mt cht khi mo DCP(0,2% so vi PVCr) to thnh GMA - PVCr:

- GMA - PVCr phn ng vi NBR to thnh copolyme khiPVCr- GMA - NBR:

- Phn ng khu mch NBR trong copolyme khi PVCr- GMA- NBR bng lu hunh to thnh copolyme khi PVCr - GMA -NBR khu mch:


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Cc copolyme khi PVCr - GMA - NBR to thnh trong qutrnh lu ho ng ng vai tr ca cht nhho bmt ranh giicc polyme NBR v PVCr, do , chng gim ng sut b mt,gim kch thc pha NBR v tng kh nng phn tn ng uNBR trong PVCr.

S. R. Chowdhury v cng s chto polyme blend tcao supolyetylen clorosunfonat ho (CSPE) v EVA trong thit b nhaho Brabender. Hcht khu mch cho cao su CSPE bao gm cccht xc tin TMTD, dibenzothiazyl disulfit, cc cht hot ho luho oxit magie v Pb3O4. u tin, nha EVA c nng chy 100oC, sau a cao su CSPE v hcht khu mch cao su vonha EVA nng chy, tip tc trn hn hp trn trong 8 pht v totm polyme blend EVA/CSPE trn my cn 2 trc. Cui cng, tmpolyme blend c p lu ho trn khun p 150oC t10 n 60pht. Trong qu trnh ny nha EVA nng chy ng vai tr ktdnh cc ht cao su CSPE khu mch. co ngt v bn nhit

ca polyme blend tng theo hm lng cao su CSPE [54].Ngi ta thng dng EPDM-g-MA trong qu trnh lu ho

ng PA/EPDM. Rezol khng th dng cho polyme blendPA/EPDM v khng ch pha EPDM m c pha PA cng b khumch lu ho ng trong polyme blend PA/EPDM. Peoxit thchhp cho lu ho ng polyme blend ny v khi sdng DCP trongqu trnh lu ho ng polyme blend HDPE/EVA, cm un tch


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lu do (storage moduli) v m un tn hao (loss moduli) capolyme blend PA/NBR u tng [55]. Khi lu ho ng polymeblend PA/NBR c cht tng hp CPE, nht chy tng i

tng, kch thc pha phn tn gim khi tng hm lng CPE tihm lng ti hn, bmt ranh gii pha bo ho CPE [56].

Vi polyme blend PP/NBR lu ho ng bng rezol, c ththu c cao su nhit do chu du. Phn ng gia PP bin tnhrezol vi NBR c nhm th (nh NBR cha nhm amin cuimch) to thnh polyme blend khu mch. G. Naderi v cng s lu ho ng polyme blend PP bin tnh/NBR trn thit btrnni trng thi nng chy (185oC). u tin, a PP vo bungtrn v trn nha PP trong 3 pht. Sau , a NBR vo nha PP

nng chy v trn tip 3 pht. a cht xc tc clorua thic vobung trn v thc hin lu ho ng polyme blend PP bintnh/NBR trong 3 pht. M men xon ca polyme blend PP bintnh/NBR tng theo hm lng nha phenol (do phn ng gialin kt i ca NBR vi nhm metylen gn vi vng croman) vcht xc tc clorua thic [57].

Ngoi khu mch polyme blend bng hlu ho, alkyl phenol,nha rezol hay cc peoxit, ngi ta cn khu mch cc polyme bngbc x, v dbc xgamma. Nhqu trnh ny m cc tnh cht c

l, tnh cht nhit, bn ho cht v dung mi ca polyme blendtng ln.

III.4. Trng hp monome trong mt polyme khc

Mt phng php chto polyme blend kh n gin l trng hpmt monome trong s c mt ca mt polyme khc. D.Cangialosi v cng s trng hp MMA trong cao su SBR(25pkl styren, 75pkl butadien). u tin, SBR c ho tan trongMMA khong 2 giv c khuy mnh. Sau , a 0,3% cht khimo lauryl peoxit v 0,45% cht chuyn mch lauryl mecaptan vohn hp phn ng, khuy tip 10 pht trc khi tin hnh phn ngtrong kh nit nhit 90oC. Vi nhit ny, cht khi molauryl peoxit bphn hunhanh chng. Khi qu trnh trng hp xyra khong 30%, dng khuy do nht dung dch tng mnh, rtdung dch vo cc ngn (cell) trng hp v yn cho phn ng xyra hon ton. Thi gian v nhit x l cc ngn trng hp nh


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sau: u tin 20 gi60oC trong thit bcha nc, sau 1,5 gi80oC, 2 gi100oC v 2 gi120oC trong l sy. Cui cng, ccngn trng hp c lm ngui xung nhit phng. Ho tan snphm trong THF, sau sdng dung mi axeton ho tan MMAkhng tham gia phn ng trng hp v kt ta polyme blend thuc. thu phn kt ta, tin hnh ly tm trn my ly tm vi tc20.000 vng/pht, sau sy trong l sy n khi lng khngi [58].

Polyme blend PE/polyvinyl axetat (PVAc) c chto theophng php ti ch (in situ) trong bnh phn ng lm bng thpkhng g. PE nn c xp l lng trong bnh phn ng nh ccmt li. a vo bnh phn ng dung dch monome VAc v chtkhi mo phn ng l 2,2- azobiisobutyronitril (AIBN) (1% so vikhi lng monome). Khng kh trong bnh c thay thbng khCO2. Sau khi h thng t ti cn bng nhit (35

oC), bnh phnng c np p sut 6 MPa CO2 bng bm CO2, gia nhit phnng ti 80oC trong khong 0,5 gi. Sau khi phn ng xy ra honton, hnhit bnh phn ng xung 10oC (bng nc bnngoi). X p bnh phn ng v p sut thng. Cc tm polymeblend PE/PVAc c sy chn khng nhit phng sau khi trchly bng axeton loi bcc cu tkhng tham gia phn ng vPVAc to thnh trn bmt polyme blend PE/PVAc [59].

M. J. M.Abadie v cng s trng hp MMA trong cao su PBvi h khi mo oxy ho - kh metyl etyl keton peoxit - cobanoctoat trn thit bphn ng TROMBOMAT c thit bghi lin tcs thay i nht ca hn hp phn ng, thi gian v nhit trng hp. u tin, cao su PB c ho tan trong dung mi MMA.Sau , hn hp cao su PB trong MMA c a vo thit bphnng. Va khuy hn hp phn ng va thm vo hkhi mo oxyho - khmetyl etyl keton peoxit - coban octoat. Phn ng trnghp MMA trong cao su PB xy ra cho n khi khng cn s thay

i nht dung dch phn ng [60].Hin nay, trng hp MMA trong copolyme EVA thu c

polyme blend PMMA/EVA c 2 pha ng lin tc ang c quantm nhiu v khnng ng dng thng mi ca n [50].

Polyme blend dn in trn c s poly (vinyliden florua)(PVDF) v polyanilin (PANI) c tng hp bng cch trng


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hp ha hc anilin trong hn hp ca PVDF v dimetylformamitvi ammonipersulfat v axit p-toluensulfonic l cc cht pha tp(dopant).

Phn ng trng hp anilin

Quy trnh tng hp phng th nghim polyme blendPVDF/PANI tiu biu nh sau: u tin ho tan 1g PVDF trongdimetylformamit 70oC. Lm ngui dung dch PVDF xungnhit phng, thm 0,5g anilin vo dung dch PVDF c khuy.Sau , a t t vo hn hp trn dung dch ca 1,22g

ammonipersulfat v 4,28g axit p-toluensulfonic trong 20mldimetylformamit. Tip theo, a ttvo dung dch trn 44,5mlcloroform. Phn ng trng hp anilin xy ra nhit phngtrong 2 gic khuy lin tc. Kt thc qu trnh trng hp anilintrong PVDF, rt nc ct vo dung dch kt ta polyme blendthu c. Tin hnh lc v ra polyme blend PVDF/PANI bngnc ct v dung dch khan ca axit p-toluensulfonic 0,1M. Sau, sy polyme blend PVDF/PANI di p sut chn khng 70oC trong 24 giv sy tip trong iu kin trn 24 githuc bt polyme blend PVDF/PANI mu xanh xm. Hiu sut

tng hp polyme blend PVDF/PANI khong 88,2% [61].

III.5. Phng php to cc mng li polyme an xen

Mt phng php ch to polyme blend kh ph bin hin nay lto mng li cc polyme an xen, mc vo nhau (interprenetratingpolymer networks, IPN). Cc IPN c xem nh polyme blend,


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trong c t nht mt monome trng hp v khu mch polymeto thnh trong mt polyme khc. Ni mt cch khc, IPN l skthp gia 2 hoc nhiu polyme bng cc lin kt vt l, t nht mttrong cc polyme c tng hp hoc khu mch vi sc mt capolyme kia [62]. Khc vi ch to polyme blend tng hp phnng, khi chto cc IPN, cn phi trnh cc phn ng ho hc xyra gia cc polyme thnh phn. Khi 2 polyme thnh phn trong hcng c khu mch s thu c mng li cc polyme an xenhon ton (full-IPN). Khi mt trong 2 polyme thnh phn ckhu mch sthu c bn IPN (semi-IPN). Nguyn tc chto ccIPN t2 monome nhsau: u tin 2 monome c trn ln dnglng, sau phn ng trng hp xy ra vi sc mt ca cht khimo v to thnh 2 polyme thnh phn. Cn cvo cht khu mch

v mc ch sdng, ngi ta c thcho mt trong 2 polyme thnhphn khu mch. C 2 phng php chnh ch to IPN. lphng php mt giai on v phng php hai giai on. Trongphng php mt giai on, 2 polyme c ch to ng thi vc lp vi nhau. Trong phng php hai giai on, tin hnh chto ln lt tng polyme. Ni chung, phng php mt giai onc sdng phbin hn do tin li v c hiu qukinh t.

T. K. Das v cng s tng hp cc IPN bng cch ngng tPU ca du tng (du castor) v isophoron diisoxyanat vi cacdanyl

acrylat/cacdanyl metacrylat khi s dng etylenglycol dimetacrylatlm cht khu mch v benzoyl peoxit (BPO) lm cht khi mo[63, 64]. Hm lng monome trong hn hp nh hng ti cu trchnh thi v hm lng kt tinh trong cc IPN.


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IPN ca PU (du tng + isophoron diisoxyanat) vi cacdanyl metacrylatc etylenglycol dimetacrylat lm cht khu mch

CH-O-CO-(CH2)7-CH=CH-CH2-CH(OH)-(CH2)5-CH3

CH2-O-CO-(CH

2)7-CH=CH-CH

2-CH(OH)-(CH

2)5-CH

3

CH2-O-CO-(CH

2)7-CH=CH-CH

2-CH(OH)-(CH

2)5-CH

3

NCO

NCO

CH3

H3C

CH3

CH2-O-CO-(CH

2)7-CH - CH-CH

2-CH(O)-(CH

2)5-CH

3

CH2-...

CH-...

-(CH2)7-CH=CH-CH2-CH=CH-CH2-CH=CH2

CH2-O-CO-(CH

2)7-CH=CH-CH

2-CH(O)-(CH

2)5-CH

3

NH

NCO

CH3

H3C

CH3

COO-CO-C(CH

3)=CH

2

R

CH2-...

CH-...

(CARDANYL METACRYLAT, CM)

(PU)

(DuCASTOR)

(ISOPHORONDIISOXYANAT)

45oC

Khuy

Mt xch PUMt xch CM

BPO

ETYLENGLYCOL DIMETACRYLAT

75 oC

R:


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A. P. Mathew v cc cng s[65-67] ch to cc IPN trncsCSTN v PS bng kthut lin tip (sequential technique) vicc cht khi mo nhbenzoyl peoxit (BPO), azobisizobutyronitril(AIBN), dicumyl peoxit (DCP) v cht khu mch nh divinylbenzen (DVB). u tin CSTN c khu mch bng mt chtkhu mch, sau tin hnh trng hp styren v khu mch PSbng mt cht khi mo v mt cht khu mch. Cc qu trnh trnc m tnhsau:

- Khu mch pha CSTN:

CSTN c cn t mch v ho do trn my cn 2 trc. TrnDCP (4pkl) vi CSTN cn trn. Nh my o lu binMonsanto xc nh c thi gian khu mch ti u. Hn hp

CSTN c khu mch/li ho trn my p thu lc 160o

C thu c cc tm CSTN khu mch.

- Trng hp v khu mch pha PS vi cc cht khi mo BPO,DCP v AIBN:

+ Cc tm CSTN khu mch c ngm trong monome styrenkhng c cht c chv c 1% cht khi mo BPO v 2%, 4% hoc6% DVB l cht khu mch cho pha PS. Cc tm CSTN ctrng trong khong thi gian khc nhau cc IPN c hm lngPS khc nhau. Cc mu CSTN trng c gi0oC trong vigit c phn bcn bng ca monome styren trong pha lintc. Mng CSTN/styren c cht khi mo v cht khu mch cgia nhit 80oC trong 6 gi v 100oC trong 2 gi qu trnhtrng hp v khu mch monome styren xy ra hon ton. Cc tmIPN CSTN/PS cng c sy trong tsy chn khng ui htmonome styren khng tham gia phn ng.

+ Tng t, a 1% DCP hoc 0,5% AIBN v 2%, 4% hoc6% DVB vo monome styren. Sau , ngm CSTN khu mch vohn hp monome styren ni trn. Mng CSTN/styren c cht khimo v cht khu mch c gia nhit 80oC trong 6 gi v 100oC trong 2 gi qu trnh trng hp v khu mch monomestyren xy ra hon ton. Cc tm IPN CSTN/PS cng c sytrong tsy chn khng ui ht monome styren khng tham giaphn ng.


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Trong cc mu polyme blend - IPN CSTN/PS, hm lng PSc thln ti 70%. Tnh cht cca polyme blend - IPN CSTN/PSs dng cht khi mo DCP ln hn so vi polyme blend - IPN

CSTN/PS sdng cc cht khi mo BPO v AIBN.M. S. Lin v cng s ch to cc IPN trn c s etylen

dimetacrylat (EDMA) v diglycidyl ete ca bisphenol A (DGEBA)sdng isophronediamin v BPO lm cc cht khu mch. Hn hpvi cc t l EDMA/DGEBA khc nhau (0/100; 18/82; 25/75;30/70; 37,5/62,5; 50/50), isophronediamin v BPO (0,5% so viEDMA) c trn u ri rt vo khun lm bng Teflon v tinhnh khu mch sb45oC trong 3 gi, sau khu mch 70oCtrong 4 gi, kt thc bng khu mch 90oC trong 2 gi. Cc bn

IPN trn c s2-hydroxymetyl metacrylat (HEMA)/DGEBA theocc t lnhtrn, isophronediamin v BPO (0,5% so vi EDMA)c chto theo cc chkhu mch tng t. Kt quxc nhtnh cht cca cc polyme blend IPN v bn IPN cho thy, cngmt hm lng epoxy, cc IPN c m un n hi v dn di khit ln hn so vi cc bn IPN [68]. Khi ch to bn IPNPMMA/DGEBA, cc qu trnh trng hp MMA v khu mch hpcht epoxy DGEBA xy ra ng thi [69]. Monome MMA ctrng hp theo cchgc tdo nhcht khi mo AIBN (0,04%

so v

i MMA) trong s

c mt c

a oligome DGEBA v ch

t khumch anhydrit hexahydrophtalic (t l khi lng 1:1 so vi

DGEBA). Sau khi trn u MMA/AIBN vi hn hpDGEBA/anhydrit hexahydrophtalic, dung dch ng th c rtvo khun nhm ri a vo l nhit 80oC trong 4 gi, sau khu mch 100oC trong 4 gi gia tc qu trnh trng ngngDGEBA v kt thc bng khu mch 120oC trong 6 gi.

Cc bn IPN ca PU/PS cha 30% PU c ch to bngquy trnh lin tip ti ch(in-situsequential). Trong quy trnh ny,cc cu tc s dng l Desmodur N (adduct mch thng cahexametylendiisoxyanat), POPG (polypropylen glycol), styren,AIBN, cht n nh octoat thic v PS anion ho. Trng hp styrenc mt AIBN, cht n nh octoat thic c bt u 69oC, tiptheo trong 2 ginhit phng l thi gian mng PU to thnhhon ton (trc khi trng hp styren, PU c to thnh hon ton,v vy, s tch pha c ngn nga do mng PU va to thnh).Mc d cc hm lng nhPS anion ho c ho tan trong hn


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hp phn ng ban u, mi trng phn ng vn lun ng nht vtrong sut. Cc IPN ca PU/PMMA c chto bng cc quytrnh ti chnhquy trnh lin tip ti chv ng thi ti ch(in-situ simultaneous). Trong quy trnh lin tip ti ch, hn hp gmDesmodur L75 (adduct ca 1,1,1-trimetylol propan/toluendiisoxyanat), POPG (polypropylen glycol), metylmetacrylat, TRIM(trimetylol propan trimetacrylat vi 100ppm cht c chmetyletylhydroquinon) v AIBN c trn u, sau a vo 1%cht n nh octoat thic. Hn hp trn c rt vo khun thutinh v ginhit phng khng c nh sng to gel ca PU.Sau chuyn khun thutinh c PU c to gel sang l (gia nhit n 60oC). Trong quy trnh ng thi ti ch (in-situsimultaneous), hn hp c gia nhit 60oC ngay sau khi rt vo

khun. C2 loi IPN ca PU/PMMA to thnh theo quy trnh lintip ti chv ng thi ti chu c mt m 75oC v 3gi trong tsy chn khng 120oC [70]. Tng t, cc bn IPNca poly(dimetyl siloxan)/poly(N-isopropyl acrylamit) cng c ch to bng cc quy trnh lin tip ti ch v ng thi tich, trong poly(dimetyl siloxan) mch thng c to thnh theocchtrng hp gc tdo c mt cht khi mo AIBN [71].

C. U. Jr. Pittman v cng s chto cc bn IPN tPVC v5-15% di-(4,4- diisoxyanato phenyl) metan bng cch trn trc tip

di-(4,4- diisoxyanato phenyl) metan dng lng vi cc ht PVCkhng ho do (c 30% lxp) trn my trn rn tc cao (1000vng/pht) 21-24oC trong 1- 2 pht, sau tip tc trn trn mycn 2 trc 50oC cho n khi 2 thnh phn trn u hon ton. Sau, tin hnh p v khu mch hn hp trn khun nhm 145oCtrong 45 pht di p lc (my p thulc) 320-450atm. Trong qutrnh gia nhit 145oC, di-(4,4- diisoxyanato phenyl) metan tiptc chuyn ng vo bn trong khi PVC, ng thi phn ng khumch di-(4,4- diisoxyanato phenyl) metan cng xy ra. Tnh cht

cca cc bn IPN PVC/di-(4,4- diisoxyanato phenyl) metan lnhn nhiu so vi PVC ban u [72].

Cc hydrogel l cc IPN v bn IPN c cc lin kt hydro giacc i phn t ca cc polyme thnh phn [73-80]. Phng H vcng s ch to cc IPN trn c s PU khu mch vipolydimetylaminetylmetacrylat hoc poly axit metacrylic (PMA)[73, 74]. PU khu mch c iu ch t4,4-dicyclohexylmetan


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diisoxyanat, diol mch di (copolyme 3 khi etylen oxit/propylenoxit/ etylen oxit), cht khu mch (trietanolamin), cht ko dimch (diol mch ngn-1,4-butaneldiol) vi cht xc tc l dietyl

thic dibutyl axetat. Tin cht PMA c iu ch t axitmetacrylic c mt cht khi mo AIBN (1% mol) v 1,4-butaneldioldimetacrylat (2% mol) c s dng lm cht ng rn. Cc IPNca PU khu mch v tin cht PMA c tng hp theo phngphp hai giai on trnh phn ng gia nhm isoxyanat vinhm cacboxyl ca axit metacrylic. Sn phm IPN cui cng thuc khi tin hnh phn ng trng ngng tin cht PMA trong PUkhu mch 60oC trong 12 gi.

Hydrogel bn IPN trn c s poly(N-vinylpyrolidon) (PVP)

khu mch v poly axit acrylic mch thng c tng hp theo 3bc: u tin, chto poly axit acrylic mch thng bng phn ngtrng hp gc tdo monome axit acrylic nhcht khi mo AIBN,sau ch to poly(N-vinylpyrolidon) khu mch bng phn ngtrng hp huyn ph ca N-vinylpyrolidon vi cht khi mo AIBNv cht khu mch N,N-metylen bisacrylamit. Cui cng, kt hpdung dch nc ca poly axit acrylic v cc ht xp ca poly(N-vinylpyrolidon) (tlmol thch hp ca 2 polyme l 1:1 v 2:1) rin nh hbng qu trnh lm ng - ph ng hn hp nhiu ln.

Nh

b

c ny, hydrogel bn IPN

c to thnh. Sau khi s

y kh,hydrogel bn IPN c hnh dng tng tcc a rt mng.

Phng php phhng ngoi bin i Fourier v phng phpnhit lng qut vi sai chng minh stn ti ca lin kt hydrogia nhm cacbonyl trong mng poly(N-vinylpyrolidon) v nhmcacboxyl trong mch poly axit acrylic [75].


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Thi Hong164

Hydrogel bn IPN ca acrylamit v axit acrylic c tnghp bng cch ng trng hp khun (template copolymerization)trong poly(allylammonium clorua) - pha lin tc v N,N-metylenbisacrylamit lm cht khu mch. Acrylamit c trn vi axitacrylic to thnh hn hp cha 30, 35, 40 hoc 50% mol axitacrylic v nng monome tng 5%. Cht khi mo trng hp

2,2-azo-bi-(2-amidinopropan) diclorua (0,3% so vi khi lngmonome tng) v cht khu mch N,N-metylen bisacrylamit (1,5%so vi khi lng monome tng) c a vo hn hpmonome/poly(allylammonium clorua). Qu trnh ng trng hpc tin hnh 55oC trong 12 gi, sau lm lnh xung nhit phng. Ra hydrogel bn IPN (c ct nh) trong nc ct 48 giloi bcc monome khng tham gia phn ng [76].

Mt trong nhng sn phm IPN thng mi c ng dng chto cc chi tit t l hn hp polyme cha PP v EPDM. Khi

cc on etylen ca EPDM di kt tinh, c PP ln EPDMc an mc ng thi bng cc vng kt tinh ca c 2 polyme(crystalline domains) m khng cn phi khu mch chng. Phngphp IPN c sdng ngy mt rng ri chto polyme blendc nhng tnh cht c bit. Nhc im ca phng php ny lvt liu thu c rt kh ti sinh [5].

III.6. Cc phng php khc chto polyme blend

Chto polyme blend thn hp cc latex polymeSo vi phng php ch to polyme blend t dung dch, phngphp trn hp cc latex polyme c nhiu u im hn v a sccsn phm polyme trng hp trong nhtng tn ti di dng ccht/keo polyme nh tng (latex) vi mi trng cht mang lnc. Qu trnh trn hp cc latex polyme c thtin hnh ddng,polyme blend thu c c cc ht polyme phn bng u vo


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nhau. i vi phng php ny, cn ch l cc latex polyme tnti n nh trong mi trng nc nh cc cht hot ng bmt/cht nhho, cht n nh, cht iu chnh pH v cc cht m.

Nng ca cc hp cht trn, nhit khuy trn, tc khuytrn l nhng yu t quan trng nh hng ti kh nng tnghp, mc phn tn ca cc latex polyme vo nhau v tnh chtca polyme blend [2, 3, 5].

Nhc im cbn ca phng php ny l kh c th tchht cht nh ho, cc ph gia khc cng nh nc khi polymeblend, do cc tnh cht c-l, ho, nhit, in ca polyme blendbgim i.

Phng php c chuyn nha

Polyme blend trn c s nha nhit do v nha nhit rn (nhaphn ng) c ch to bng cng ngh c chuyn nha (resintransfer moulding - RTM) [81]. Nha nhit do c s dng lpolyete imit v nha phn ng c s dng l nha epoxy(DGEBA). Cc cht ng rn nha epoxy l cc diamin vng bo(IPD, 3DCM, MNDA), diamin vng thm (DEDTA 80). Nguyntc ch to polyme blend nh sau: a nha nhit do vo khuncng vi cht phgia, cht gia cng. Sau , ho tan v khuchtn nha nhit do bng tin cht (precusor) ca nha phn ng(a vo nhbm cht lng). Trong khun xy ra phn ng ngrn nha nhcc cht ng rn diamin vng. nht ca hn hpphn ng tng theo thi gian trng hp. Nhit ng rn nhaDGEBA bng DEDTA 80 thch hp trong khong 100-150oC. Ktthc qu trnh chto polyme blend nha nhit do/nha nhit rnsau khi tho khun. Bn cht ca qu trnh chto polyme blend lkhu mch phn ng nha epoxy bng hp cht diamin vng tronghn hp vi nha polyete imit.


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77. Y. Zhao, J. Kang, T. Tan, Salt-, pH- and temperature reaponsivesemi-interprenetrating polymer network hydrogel based on

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Chng IV

CC BIN PHP TNG CNG TNG HPPOLYME BLEND

chto polyme blend c cht lng tt v kt hp c cc uim ca polyme thnh phn, cc polyme trong hphi c khnng

ha trn, tng hp hon ton hoc tng hp mt phn vi nhau.Hin nay, ngi ta gii quyt vn tng hp ca cc polymekhng c hoc t c khnng tng hp nhsau [1-5]:

a, Tng hp khng phn ng: bin tnh mt trong 2 polyme tng khnng trn ln, phn tn v tng tc 2 polyme; thm vocc polyme, copolyme khi, copolyme nhnh v copolyme ghphoc cc cht phgia khng tham gia phn ng nhng c khnngtrn ln v tng tc vi cc polyme.

b, Tng hp nhcc tng tc c bit (cn gi l tng tcring): gn vo mch ca mt hoc c2 polyme cc nhm c khnng tng tc c bit (tng tc ring) v khng to thnh linkt cng ho trgia 2 polyme.

c, Tng hp phn ng: cc polyme c khnng phn ng, cbit l phn ng gia cc nhm chc hot ng ho ca cc polyme,phn ng chuyn vto thnh copolyme ti ch(in-situ) trong qutrnh trn/blend ha cc polyme. Copolyme to thnh ti chngvai tr ca cht tng hp cho cc polyme ban u nhtng cngtng tc, trn ln v phn tn cc polyme vo nhau.

Xu hng phbin hin nay l bin tnh polyme bng cch gnvo i phn tpolyme cc nhm c khnng phn ng, sdngcc copolyme c khnng phn ng vi mt hoc c2 polyme to thnh copolyme ti ch trong qu trnh trn hoc s dng cchp cht thp phn tc khnng phn ng. Di y l cc binphp cthnhm tng cng tng hp cc polyme.


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IV.1. Bin tnh polyme

Phng php ny thng c p dng cho polyme blend c mtpolyme khng phn cc hoc t phn cc v mt polyme c cc.

tng khnng tng tc gia 2 polyme ni trn, tin hnh chc hohay cc ho polyme khng hoc t phn cc bng cch gn vo ncc nhm c kh nng phn ng, cc monome c cc hoc gimkhnng phn cc ca polyme c cc. Cc nhm c khnng phnng v nhm c cc gn vo polyme khng phn cc hoc t phncc c thphn ng vi nhm c khnng phn ng hoc tng tcc bit vi nhm c cc trong polyme c cc. Nhcc phn ng,tng tc trn m cc polyme c kh nng tng hp hon tonhoc tng hp mt phn vi nhau.

A. Lazzeri v cng s nghin cu polyme blend trn cspolyamit 6 (PA6) vi polyetylen ttrng rt thp (VLDPE). Trong VLDPE c bin tnh hay chc ho bi anhydrit maleic(VLDPE-g-MA) v dietylmaleat (VLDPE-g-DEM). Vi cng mtt l ca 2 polyme thnh phn (80/20), cc polyme blendPA6/VLDPE-g-MA v PA6/VLDPE-g-DEM c bn ko t v bn nt ln hn polyme blend PA6/VLDPE (bng IV.1). Kchthc pha phn tn VLDPE, VLDPE-g-MA v VLDPE-g-DEMtrong PA6 ln lt l 5-8, 1 v 0,2m [6]. R rng l bin tnh

VLDPE bng MA v DEM gp phn tng tnh cht cv gimkch thc pha phn tn trong polyme blend PA6/VLDPE. PhnVLDPE trong VLDPE-g-MA v VLDPE-g-DEM ddng trn lnv phn tn vo pha VLDPE, phn MA v DEM tng tc vi ccnhm amit v amin cui mch ca PA6. c bit l nhm amin cuimch ca PA6 phn ng vi nhm MA ca VLDPE-g-MA tothnh copolyme ti ch(in-situ) VLDPE-b-PA6. Nhcopolyme nym VLDPE c thtng hp hn vi PA.

Bng IV.1. Tnh cht cca polyme blend PA6/VLDPE vpolyme blend PA6/VLDPE bin tnh bng MA v DEM [6].

Polyme blend bn ko t(MPa)

bn nt(kJ/m2)

PA6/VLDPEPA6/VLDPE-g-MAPA6/VLDPE-g-DEM

424743

3117,5


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Chng IV. CC BIN PHP TNG CNG TNG HP POLYME BLEND 177

So vi polyme blend PA/copolyme etylen-vinyl axetat (EVA),polyme blend PA/EVA-g-MA c pha phn tn ng u hn trongpha lin tc, hin tng kt tca pha phn tn gim r rt. bn

va p ca polyme blend PA/EVA-g-MA ln hn so vi polymeblend PA/EVA v l hm ca hm lng MA ghp vo EVA.Chnh phn ng gia MA trong EVA-g-MA v nhm amin cuimch ca PA to thnh copolyme ti chPA-b-EVA bmt ranhgii 2 pha thc y tng hp PA v EVA-g-MA [7].

Sau khi ghp monome c cc nh metyl metacrylat (MMA)vo etylen-propylen-dien monome (EPDM) bng phn ng ngtrng hp ghp, copolyme EPDM-g-PMMA trthnh c cc. Trngin pha ca EPDM-g-PMMA (phn trm ghp MMA vo

EPDM 26%) v copolyme styren-acrylonitril (SAN) xut hin nhitho tan ti hn di (LCST). Nhvy EPDM-g-PMMA v SAN ho trn, tng hp vi nhau tt ccc tl. iu ny c thgii thch bi tng tc lng cc gia nhm cacbonyl (C=O) trongEPDM-g-PMMA vi nhm nitril CN trong SAN. Trong khi,polyme blend EPDM/SAN hon ton khng tng hp v ch cnhit ho tan ti hn trn (UCST) [8].

IV.2. Sdng cht tng hp l polyme

IV.2.1.a vo cu tthba l copolyme hoc polyme

a vo copolyme khi v copolyme ghp chto trc

y l mt trong nhng bin php c sdng nhiu do hiu qucao ca cc cht tng hp trn cscc copolyme khi, copolymenhnh v copolyme ghp chto trc. C nhiu copolyme khicu trc mch thng, copolyme nhnh v copolyme ghp trthnhcc cht tng hp c thng mi ho nh: Exxelor PO X1 1015l polypropylene-g-anhydrit maleic (PP-g-MA) vi 0,4% nhm MAca hng Exxon, polyetylen-g-axit acrylic (PE-g-AA) ca Cng tyHo cht Qung Chu, Trung Quc, terpolyme Lotader AX - 8660cha 5% etylen ca hng Atochem Cc copolyme khi vcopolyme ghp dng lm cht tng hp c ch to c trongdung dch ln trng thi nng chy. p ng yu cu ca chttng hp, cc copolyme khi hoc copolyme nhnh phi c mtkhi hoc mt nhnh c khnng tng hp tt vi mt polyme v


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nhnh hoc khi kia phi c khnng tng hp tt vi polyme cnli. Cc copolyme thng c 2 khi to thnh t cc mt xchmonome ca mi polyme thnh phn. Nh vy, khi c cngmonome vi polyme thnh phn sc cng bn cht v cu to hohc tng t, v vy chng c khnng trn ln, phn tn tt vinhau. Copolyme khi c cc khi to thnh tcc monome gingvi 2 polyme ban u ng vai tr nhmt cht hot ng bmtv cht kt dnh 2 polyme. N gp phn gim ng sut bmtranh gii 2 pha polyme. T sc mt gi trti hn mi ca hc thit lp, tng ng vi n l mt gi trcc tiu ca ngknh pha phn tn v tn ti hm lng ti u (hm lng ti hn)cht tng hp bo ho bmt ranh gii 2 pha polyme. Nulng cht tng hp a vo ln hn gi trny, ln ca pha

phn tn skhng thay i ng kna. Hm lng cht tng hpti u bo ho bmt ranh gii 2 pha gim tuyn tnh theo sgim khi lng phn tca cc polyme thnh phn [5].

Thnh phn, khi lng phn t ca cc cht tng hp(copolyme khi, copolyme nhnh v copolyme ghp) v tnh cht,cu trc ca polyme blend c mi quan hcht chvi nhau. Hiuqutng hp ca cc copolyme khi c thc so snh theo tlkhi lng phn tca polyme thnh phn v copolyme. Nu ltlkhi lng phn tca polyme A v khi A trong copolyme,

l tlkhi lng phn tca polyme B v khi B trong copolyme,copolyme l cht tng hp km hiu qu khi > 1 v > 1.Copolyme c hiu qu tng hp ti u khi < 1 v < 1 v ltng nht khi = < 1. C th thy v gim khi khi lngphn t ca polyme gim v khuynh hng copolyme phn bti bmt ranh gii 2 pha ln hn, do hiu qutng hp cngtng ln. C thgim hm lng copolyme sdng khi khi lngphn tcc polyme thnh phn gim.

Trng hp ph bin nht tng cng tng hp polyme

blend A/B l sdng cht tng hp copolyme A-B v to thnh hA/B/A-B, trong copolyme khi A-b-B hoc copolyme ghp A-g-B ng vai tr ca cht kt dnh 2 pha A v B v copolyme A-Bc gi l copolyme entropy. Khi lng phn ttrung bnh cacopolyme A-B phi c iu chnh cho tng loi polyme blend vt liu c cc tnh cht mong mun, trong di ca tng khicng ln, hiu ng tng hp cng cao. Bn thn cht tng hp


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phi c di ln gim sc cng bmt ranh gii 2 pha vto thnh s ri cun cng nhan mc vi cc polyme A v B.Tuy nhin, di khng c qu ln trnh kt tto thnh

pha thba cng nhto thnh cc mixen [5]. Vi cht tng hp lcopolyme A-C, khi khi C trn ln tt vi polyme B, copolyme nyng vai tr ca mt copolyme entalpy. Vi copolyme D-E bt kc cc thnh phn D v E khc hn vi thnh phn cc polyme A vpolyme B vn c th ng vai tr ca cht tng hp cho ccpolyme A v polyme B nu D khng tng hp vi polyme Anhng tng hp hn vi polyme B [5]. Mt s cht tng hpcopolyme khi v copolyme ghp c trnh by bng IV.2.

Bng IV.2. Cc cht tng hp copolyme cho polyme blend [5].

Dng blend Polyme thnht

Polyme thhai Cht tng hp

A/B/A-Bkhi

PBT PS PS-b-PBT

PE hocHIPS

PE hoc HIPS HPB-b-PS

PBT hocPS

PBT hoc PS PS-b-PBT hoc

PS-b-PET

A/B/A-Ckhi

PET PS PS-b-PCl

PVC PS PCl-b-PS hoc

PMMA-b-PS

PVF PS PS-b-PMMA

PS PC PS-b-PCl

PS PE HPB-b-PS


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SAN SBS PS-b-PMMA hoc

PB-b-PMMA

ABS PE HPB-b-PMMA

PVC SEBS HPB-b-PMMA

PET HDPE S-EB-S

PS/PPOhoc PBT

BT hoc PS/PPO PS-b-PET hoc

PS-b-PBT

A/B/C-Dkhi

PE HIPS HPB-b-PS

PE PS SBS, SEBS

PPO SAN PS-b-PMMA

SAN PPO PS-b-PMMA

A/B/A-Bghp

EPDM PMMA EPDM-g-PMMA

PF PMMA hoc PS PF-g-PMMA/PF-g-PS

PBT PS PBT-g-PS

PE PS PE-g-PS

PE PA PE-g-PA

(Tn y ca cc polyme v copolyme trang cc tvit tt)

Khi s dng cc copolyme lm cht tng hp cho polymeblend, cc copolyme khi c hiu qu cao hn copolyme ghp vcc copolyme ghp c nhnh kh thm nhp vo lp tip xc 2 phapolyme. Hnh IV.1 m t v tr ca cc copolyme 2 khi, 3 khi,nhiu nhnh ghp v 1 nhnh ghp bmt ranh gii 2 pha trongpolyme blend khng ng nht.


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Hnh IV.1. Sminh hovtr ca cc copolyme 2 khi,3 khi, nhiu nhnh ghp v 1 nhnh ghp bmt ranh gii

2 pha trong polyme blend khng ng nht [5].

Trong polyme blend LDPE/HIPS, cc pha LDPE v HIPS phntn vo nhau rt th, hin tng tch pha rt r v kh nng bm


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Thi Hong182

dnh 2 pha km. Khi thm vo 5% HPB-b-PS, kch thc ht PSphn tn gim r rt v bm dnh bmt tng ln [5]. Minh hocho v dny trn hnh IV.2.

a copolyme EVA vo polyme blend LDPE/PA, cc tnhcht cca polyme blend LDPE/PA c tng cng, c bit lbn va p. iu ny c gii thch bi khnng bm dnhtt gia PE v EVA cng nhcc tng tc vt l gia 2 polymeEVA v PA (lin kt hydro v tng tc lng cc gia nhmaxetat ca EVA vi nhm amit ca PA) [9]. EVA nng cao khnng tng hp ca LDPE v PA. H. Zhao v cng s apoly(etylen-co-axit metacrylic) (EMAA) vo polyme blendLLDPE/copolyme ca metyl metacrylat v 4-vinyl pyridin[poly(MMA-co-4VP)] vi tl2:1. Khi hm lng EMAA trongpolyme blend l 12 v 18%, kch thc trung bnh ca pha phntn gim xung cn 1 v 0,15m [10]. Trong polyme blendLLDPE/poly(MMA-co-4VP)/EMAA tn ti cc tng tc giaMAA trong EMAA vi 4VP trong poly(MMA-co-4VP). MchLLDPE d dng trn ln vi phn PE trong EMAA vng vnh hnh. V vy, kh nng tng hp ca LLDPE vpoly(MMA-co-4VP) c tng cng [5]. Nghin cu bnko t v bn va p ca polyme blend HDPE/PET cHDPE-g-MA (hm lng MA ghp 0,19%), R. N. Brandalise v

cng s nhn thy cc tnh cht trn ca polyme blendHDPE/PET (70/30) tng r rt khi c 5 v 10% HDPE-g-MA. bn ko t ca cc polyme blend HDPE/PET, HDPE/PET/10%HDPE-g-MA ln lt l 16,8 v 17,3 MPa; bn va p ca ccpolyme blend HDPE/PET khng c, c 5 v 10% HDPE-g-MAln lt l 10,76; 43,9 v 19,8 MPa. Kh nng tng hp capolyme blend HDPE/PET tng ln nhphn HDPE trong HDPE-g-MA d trn ln vi pha HDPE, nhm MA trong HDPE-g-MAtng tc lng cc vi nhm cacbonyl trong PET [11]. Tng

t, PE-g-MA tng cng tng hp cho HDPE v cao su thinnhin epoxy ho do PE-g-MA tng tc vi cao su thin nhinepoxy ho v trn ln tt vi HDPE. PE-g-MA tng bn kot, dn di khi t v bn va p ca polyme blendHDPE/cao su thin nhin epoxy ho (70/30) nh tng kh nngbm dnh 2 pha HDPE v cao su thin nhin epoxy ho. N cnggp phn tng mc ng thca polyme blend HDPE/cao suthin nhin epoxy ho [12].


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HIPS

+ Copolyme

PS

Copolyme

Cao su

Hnh IV.2. Sphn tn HIPS trong LDPE c copolyme

HPB-b-PS [5].

Trong polyme blend PP/PE c EPDM hoc EVA, cccopolyme EPDM v EVA nm b mt ranh gii 2 pha, do chng gim ng sut bmt gia 2 pha polyme, nng cao khnngtrn ln cc i phn tPP v PE, tng cng cc tnh cht ccapolyme blend PP/PE [13- 15]. EPDM tng bn va p v bnm lca polyme blend PP/PE (90/10), cn EVA tng bn va

LDPE

PS Cao su

LDPE


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Thi Hong184

p v dn di khi t ca polyme blend PP/PE. EVA ci thinbn va p cho PP tt hn EPDM. Hiu qutng hp polymeblend PP/PE ca EPDM, EVA c 28% VA (EVA-28) v EVA c33% VA (EVA-33) tng theo thtsau: vi bn va p, EVA-33 < EVA-28 < EPDM; vi bn ko t, EPDM < EVA-28


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PP/PVC, nht ca PVC gim ng k. Ngoi ra, nguyn thydro metenyl ca PVC tng tc vi nhm cacbonyl ete v nhmamit ca HBP to thnh lin kt hydro. Do , khnng gia cng v

trn ln PP v PVC ddng hn [20]. Tng t, khi a PP-HBP(hm lng t2,5 ti 20%) vo polyme blend PP/PVC (80/20), bn ko t ca polyme blend PP/PVC/PP-HBP ln hn so vipolyme blend PP/PVC. PP-HBP ci thin khnng tng hp,bm dnh pha ca PP v PVC, gim ng sut bmt ranh gii gia2 pha PP v PVC [21].

Nng lng nt bmt ca polyme blend PS/PMMA tng hn6 ln khi s dng copolyme ca MMA vi oligosilsequioxan adin (MMA-POSS). Copolyme MMA-POSS tng kh nng tng

tc gia PS v PMMA, gim ng sut bmt gia 2 pha polyme, do, PS v PMMA tng hp mt phn [22]. Cc copolyme PC-b-PMMA v PC-b- SAN gim kch thc ca pha phn tn v ngsut b mt ranh gii gia 2 pha trong polyme blend PC/SAN(hm lng AN 24%) do khnng trn ln v tng tc tt caPC-b-PMMA v PC-b- SAN vi cPC v SAN [23]. Kch thctrung bnh ca pha phn tn tlthun vi ng sut bmt ranhgii gia 2 pha trong polyme blend PC/SAN c PC-b-PMMA vPC-b-SAN. Hiu qu tng hp polyme blend PC/SAN ca PC-

b-PMMA l

n h

n PC-b- SAN. Khi s

d

ng SAN (hm l

ng ANl 17 v 25%) cho polyme blend poly(-caprolacton)/poly(benzylmetacrylat) (PCL/PBzMA), polyme blend 3 thnh phnPCL/PBzMA/SAN ch c mt nhit thu tinh ho v polymeblend to thnh mt h ng th tt c cc t l thnh phn(cn c vo gin pha). Nh c SAN, polyme blendPCL/PBzMA ho trn/tng hp hon ton [24].

Do skhc nhau vcu to, cu trc, khi lng phn t, phn cc... nn cao su thin nhin (CSTN) v PU nhit do khng

tng hp vi nhau. Khi sdng copolyme ABS (vi hm lng t0,5 ti 2,5%) cho polyme blend CSTN/PU (10/90), bn ko tca polyme blend tng ln ng k. ABS tng cng tng tc,phn tn v bm dnh CSTN v PU, do CSTN v PU tr nntng hp mt phn [25]. nht thc ca dung dch polyme blendEPDM/CSTN cc tlkhc nhau c 10% EPDM-anhydrit maleic(EPDM-MA) trong dung mi toluen lun cao hn so vi dung dchpolyme blend EPDM/CSTN khng c EPDM-MA. Nh vy,


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Thi Hong186

EPDM-MA c tc dng lm cho EPDM v CSTN tng hp mtphn [26]. Cao su NBR va c khnng trn ln vi CSTN va ckhnng tng tc vi PVC, do kch thc ca cc pha PVC vCSTN trong polyme blend PVC/CSTN/NBR ng u hn v nhhn so vi kch thc ca cc pha ny trong polyme blendPVC/CSTN [27]. Cao su NBR tng cng khnng tng hp vci thin khnng phn tn ca PVC v CSTN vo nhau do nm bmt ranh gii 2 pha PVC v CSTN (hnh IV.3) [27, 28].

Hnh IV.3. nh hin vi in tqut ca polyme blendPVC/CSTN (nh tri) v PVC/CSTN/NBR (nh phi) [27].

a vo polyme

Ngoi cc copolyme khi, copolyme nhnh v copolyme ghp,ngi ta cn a vo polyme blend cc polyme c khnng trn lnhoc tng tc vi cc polyme trong polyme blend. Vi mtpolyme (v dpolyme C) c khnng trn ln hon ton (hoc trnln mt phn ) vi 2 polyme thnh phn (A v B), C c xem nhdung mi chung cho c2 polyme A v B. N tng cng trn lnhon ton hoc mt phn 2 polyme thnh phn [5].

Trong polyme blend 3 thnh phn PVC/PE clo ho(CPE)/EPDM, EPDM l cht bin tnh va p cho PVC nhit

thp. CPE (c hm lng clo 25, 36 v 42%) c vai tr l chttng hp cho PVC v EPDM v n c cu trc ho hc tng tvi PVC v EPDM (c s phn b ngu nhin cc khi PE cloho v cc on mch etylen). Do CPE nm bmt ranh giigia 2 pha PVC v EPDM, PVC v EPDM trn ln v bm dnhvi nhau tt hn, do , s tng hp ca PVC vi EPDM vtnh cht cca polyme blend PVC/EPDM c tng cng [5].


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dn di khi t v bn va p ca polyme blend nhit phng v nhit thp tng khi a CPE vo polyme blendPVC/EPDM (bng IV.3).

Bng IV.3. bn va p ca PVC, cc polyme blendPVC/EPDM, PVC/CPE v PVC/CPE/EPDM nhit phng

v - 12oC [5].

bn va p (J/m)Polyme blend

Nhit phng

- 12oC

PVC 25 27,5

PVC/EPDM (100/10) 12,5 22,5

PVC/CPE25 (100/10)

PVC/CPE25 (100/20)

PVC/CPE36 (100/10)

PVC/CPE36 (100/20)

PVC/CPE42 (100/10)PVC/CPE42 (100/20)

50

112,5

75

837,5

75100

30

50

30

80

3047,5

PVC/CPE25/EPDM (100/10/10)

PVC/CPE25/EPDM (100/20/10)

PVC/CPE36/EPDM (100/10/10)

PVC/CPE36/EPDM (100/20/10)

PVC/CPE42/EPDM (100/10/10)

PVC/CPE42/EPDM (100/20/10)

325

637,5

125

vat lieu polyme blend p2 4054

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