fundamentals of bctmp brightness stability
TRANSCRIPT
Fundamentals of BCTMP Fundamentals of BCTMP Brightness Stability Brightness Stability
Art J. Ragauskas
Research Objective:– Investigate mechanisms of brightness
reversion– Develop photostabilization technologies
l Project Goal:– Increase the usefulness of high-yield fibers
Fundamentals of Brightness StabilityFundamentals of Brightness Stability
Fundamentals of Brightness Stability Fundamentals of Brightness Stability Past AccomplishmentsPast Accomplishments
l Developed new UV screens for high brightness mechanical pulps
l Demonstrated that additive combinations are more effective at retarding brightness reversion than individual agents
l Discovered use of FWA as brightness reversion mitigators
Fundamentals of Brightness Stability Fundamentals of Brightness Stability Past AccomplishmentsPast Accomplishments
7577798183858789919395
-1 4 9 14 Period of Irradiation/days
Tapp
i Brig
htne
ss
75% Kraft 25%BCTMPkraft
0.1% Blankopher
1.0% Phorwite UW
1% Phorwite P
0.1% Tinopal
75% Kraft/25% BCTMP
Kraft
FWA FWA PhotostabilizationPhotostabilization Effects Effects IntroductionIntroductionl Historical Notes
– FWA employed in P&P industry– Muller reported potential economic
benefits for use of FWA for high-brightness CTMPs
– Doshi found no effect for groundwood» nature of surface lignin may be important
FWA FWA PhotostabilizationPhotostabilization Effects Effects --IntroductionIntroduction
NH
SO3Na
NHN
NN
NCH3
H3C
SO3Na
O3S
NaO3S
NHN
NN
NHH3C CH3
NHSO3Na
NaO3S
Chemical structure of FWA: Tinopal.
Na
absorbs 300-400 nm hν re-emits > 410 nm
TinopalTinopal PhotostabilizationPhotostabilization EffectsEffects
l Tinopal application maintains +85 Tappi Brightness for 8 - 12 days of continuous light exposure
l Use of radical scavenger, ZnO/TiO2, or carrier molecule (PEG or PVA) extends photostabilization effect
l UV-absorber are antagonist
FWA FWA PhotostabilizationPhotostabilization EffectsEffects
l Study thermal reversion properties of FWA treated BCTMP/kraft handsheets
l Optical characterization of BCTMP/kraft handsheets with FWA with natural & office lighting
l Study the effects of light-dark cycling on photoreversion of FWA treated BCTMP/kraft testsheets
FWA FWA PhotostabilizationPhotostabilization EffectsEffects
l Determine photostabilization effects of carrier molecules (PVA, PEG, Polyvinylpyrrolidone, commercial surfactants) with Phorwite P & UW
l Study failure mechanism(s) of FWA
General Experimental MethodGeneral Experimental Method
1
MonitorOptical Properties
Photo &/or thermalaging
Control Treated with Water
MonitorOptical Properties
Photo &/or thermalaging
Aqueous AdditiveApplied
Hardwood BCTMPor
HW BCTMP + Kraft
Results: Results: PhotoreversionPhotoreversion of Kraft/BCTMP of Kraft/BCTMP -- Effects of Effects of PhorwitePhorwite UWUW
l Employed 1.25 gr handsheetsl Applied 0.1% Phorwite UWl Mixtures of Kraft/BCTMP used
– 100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60,– 30:70, 20:80, 10:90, 0:100
l Examined Tappi Brightness with & without fluorescence
Results: Results: PhotoreversionPhotoreversion of Kraft/BCTMP of Kraft/BCTMP Effects of Effects of PhorwitePhorwite 0.1% UW0.1% UW
114
Period Irradiation/day
55
60
65
70
75
80
85
90
95
100
-1 0 3 6 9 12 15 18 21 30 36 42 54 66 90
TAPP
I Brig
htne
ss
UV 95% Kraft 95%Kraft UW 90%Kraft UW 90KraftUW 85%Kraft 85% Kraft UW 80%Kraft 80% KraftUW 70%Kraft 70% kraft
PhotoreversionPhotoreversion of Kraft/BCTMP of Kraft/BCTMP Effects of 0.1% Effects of 0.1% PhorwitePhorwite UWUW
119Period Irradiation/days
50
55
60
65
70
75
80
85
90
95
100
-1 19 39 59 79 99
TAPP
I Brig
htne
ss
UW 60% Kraft
UW 50% Kraft
UW 40% Kraft
UW 30% Kraft
UW BCTMP
UW/KraftKraft
60% Kraft
50% Kraft
40% Kraft
30% Kraft
BCTMP
Results: Results: PhotoreversionPhotoreversion of Kraft/BCTMP of Kraft/BCTMP Effects of Effects of PhorwitePhorwite UW Excluding FluorescenceUW Excluding Fluorescence
55
60
65
70
75
80
85
90
-1 19 39 59 79 99 119
Period Irradiation/days
TAPP
I Brig
htne
ss E
xclu
ding
Flu
ores
cenc
e
1%UW KraftKraft1% UW 90%Kraft/BCTMP90%Kraft/BCTMP1% UW 80%Kraft/BCTMP80%Kraft/BCTMP1%UW 70%Kraft/BCTMP70%Kraft/BCTMP1%UW 60% Kraft/BCTMP60% Kraft
Results: Thermal Reversion Studies Results: Thermal Reversion Studies For FWA Treated Kraft and BCTMPFor FWA Treated Kraft and BCTMP
l Employed 1.25 gr handsheetsl Applied 1% Phorwite UWl Handsheets stored at 28oC
Results: Thermal Reversion Studies for Results: Thermal Reversion Studies for 75% Kraft/BCTMP 75% Kraft/BCTMP TestsheetsTestsheets
83
85
87
89
91
93
95
97
-1 1 3 5 7 9 11 13Storage Period/wk
TAPPI Brightness
Control1% Phorwite P1% Phorwite UW1% Tinopal
No accelerated reversion occurring!
PhotoreversionPhotoreversion of BCTMP, Kraft, & of BCTMP, Kraft, & BCTMP/Kraft BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
l Examined 3 types of handsheets– 100% kraft, 100% BCTMP, 75%
Kraft/25%BCTMPl Varied Phorwite UW
– 0.1%, 1.0%, 1.5%, 2.0%, 3.0%, 4.0%l Examined use of carrier compound
– 0% & 1.0% PEGl Examined TAPPI brightness, with/without
fluorescence, L*a*b*, abs./scatt. coeff.
Results: Results: PhotoreversionPhotoreversion of BCTMP, Kraft, & of BCTMP, Kraft, & BCTMP/Kraft BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
50
55
60
65
70
75
80
85
90
95
100
-1 0 1 2 3 4 5 7 9 11Period Irradiation/wk
TAPP
I Brig
htne
ss
1% UW BCTMPBCTMP1% UW KraftKraft1% UW 75% Kraft/BCTMP75%Kraft/BCTMP
BCTMP
Kraft
Kraft/BCTMP
Results: Results: PhotoreversionPhotoreversion of 100%Kraft of 100%Kraft Effects of FWAEffects of FWA
80
82
84
86
88
90
92
94
96
98
-1 19 39 59 79 99
Period Irradiation/day
TAPP
I Brig
htne
ss
Kraft 0.1% uw 1% uw1.5% uw 2% uw 3% uw4% uw
Results with Phorwite UW & PEG were similar, suggesting that loss of FWA contributes to brightness loss in BCTMP
Results: Results: PhotoreversionPhotoreversion of HW BCTMP of HW BCTMP Effects of FWA + Carrier moleculeEffects of FWA + Carrier molecule
TAPPI Brightness
60
65
70
75
80
85
90
95
-1 9 19 29 39 49 59
Period Irradiation/wk
BCTMP0.1% UW1% UW1.5% UW0.1%uUW1%PEG1%UW/1%PEG1.5%UW/1%PEG
Results: Results: PhotoreversionPhotoreversion of HW BCTMP of HW BCTMP Effects of FWA + Carrier moleculeEffects of FWA + Carrier molecule
60
65
70
75
80
85
90
95
-1 9 19 29 39 49 59
Period Irradiation/wk
TAPPI BrightnessControl2% UW3% UW4% UW2%UW/1%PEG3%UW/1%PEG4%UW/1%PEG
-at charges < 2% PEG carrier molecule is effective at higher values effect diminishes
Results: Results: PhotoreversionPhotoreversion of 75%Kraft/25%BCTMP of 75%Kraft/25%BCTMP Effects of FWA + Carrier moleculeEffects of FWA + Carrier molecule
6 5
7 0
7 5
8 0
8 5
9 0
9 5
- 1 1 9 3 9 5 9 7 9
P e r io d Ir r a d ia t io n
TAPP
I Brig
htne
ss
7 5 /2 5 c o n tr o l 0 .1 % u w
1 % u w 1 .5 % u w
2 % u w 3 % u w
4 % u w 0 .1 u w /1 p e g
3 u w /1 p e g 4 u w /1 p e g
-carrier effect diminished for Phorwite UW on 75kraft/25 BCTMP
Results: Results: PhotoreversionPhotoreversion of HW BCTMP of HW BCTMP Effects of FWA without FluorescenceEffects of FWA without Fluorescence
Period Irradiation/day
85
60
65
70
75
80
-1 0 6 12 18 24 30 36 54 60
TAPP
I Brig
htne
ss E
xclu
ding
Flu
ores
cenc
e
Control 0.1% uw
1% uw 1.5% uw
2% uw 3% uw
4% uw
FWA functions more on latter stages of reversion
Note: Phorwite UW/PEG were also examined and demonstrated similar trends
Results: Results: PhotoreversionPhotoreversion of 75% Kraft/25% BCTMP of 75% Kraft/25% BCTMP Effects of FWA without FluorescenceEffects of FWA without Fluorescence
Period Irradiation/day
65
70
75
80
85
90
-1 0 6 12 18 24 30 36 42 60 72 84
TAPP
I Brig
htne
ss E
xclu
ding
Flu
ores
cenc
e
75/25 control 0.1%UW/1%PEG1%UW/1%PEG 1.5%UW/1%PEG2%UW/1%PEG 3%UW/1%PEG4%UW/1%PEG
Comparable trends observed with PEG
Note: FWA appears to influence reversion rates earlier than 100% BCTMP handsheets
Results: Solar Results: Solar PhotoreversionPhotoreversion of BCTMP, Kraft, of BCTMP, Kraft, & BCTMP/Kraft & BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
l Examined solar aging of BCTMP, Kraft, & 75% Kraft-25%BCTMP handsheets
l With & without Phorwite UWl Measured Brightness with/without
fluorescence, L*a*b*, abs/scatt. coeff.
Results: Solar Results: Solar PhotoreversionPhotoreversion of BCTMP, of BCTMP, Kraft, & BCTMP/Kraft Kraft, & BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
50556065707580859095
100
-1 1 3 5 7 9 11
Period Irradiation/wk
TAPP
I Brig
htne
ss
1% UW 75% Kraft
1% UW BCTMP
1% UW Kraft
BCTMP
Kraft
75% Kraft
Results: Solar Results: Solar PhotoreversionPhotoreversion of BCTMP, of BCTMP, Kraft, & BCTMP/Kraft Kraft, & BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
8788899091929394959697
-1 1 3 5 7 9 11
Period Irradiation/wk
L*
1% UW BCTMP BCTMP 1% UW KraftKraft 1% UW 75% Kraft 75% Kraft
Results: Solar Results: Solar PhotoreversionPhotoreversion of BCTMP, of BCTMP, Kraft, & BCTMP/Kraft Kraft, & BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-1 1 3 5 7 9 11
Period Irradiation/wk
a*
1% UW BCTMP BCTMP 1% UW Kraft Kraft 1% UW 75% Kraft 75% Kraft
Results: Solar Results: Solar PhotoreversionPhotoreversion of BCTMP, of BCTMP, Kraft, & BCTMP/Kraft Kraft, & BCTMP/Kraft -- Effects of Effects of PhorwitePhorwite UWUW
-5
0
5
10
15
20
-1 1 3 5 7 9 11
Period Irradiation/wk
b*
1% UW BCTMP BCTMP 1% UW Kraft Kraft 1% UW 75% Kraft 75% Kraft
Results: Effects of Light Cycling on Results: Effects of Light Cycling on PhorwitePhorwite UW Treated HandsheetsUW Treated Handsheets
l Employed kraft, BCTMP, & 75% kraft-25% BCTMP handsheets
l Exposed to fluorescent light x h then stored for x h.
l Measured TAPPI brightness values
Results: Effects of Light Cycling on Results: Effects of Light Cycling on PhorwitePhorwite UW UW Treated HandsheetsTreated Handsheets
60
65
70
75
80
85
90
95
100
initial 0day
1wlight
2wdark
3wlight
4wdark
5wlight
6wdark
7wlight
8wdark
9wlight
10wdark
11wlight
12wdark
Time Period
TAPP
I Brig
htne
ss
1% UW/BCTMP BCTMP1%UW Kraft Kraft1% UW(75% Kraft/25% BCTMP) 75%Kraft/25%BCTMP
BCTMP
Kraft
75%Kraft/BCTMP
1% UW/kraft
1% UW BCTMP
Results: Effects of Light Cycling on Results: Effects of Light Cycling on PhorwitePhorwite UW UW Treated HandsheetsTreated Handsheets
60
65
70
75
80
85
90
initial 0 day 1wlight
2wdark
3wlight
4wdark
5wlight
6wdark
7wlight
8wdark
9wlight
10wdark
11wlight
12wdark
Time Period
TAPP
I Brig
htne
ss E
xclu
ding
Flu
ores
cenc
e
1%UW BCTMPBCTMP1% UW KraftKraft1% UW (75%Kraft/BCTMP)75% Kraft/25% BCTMP
BCTMP
Kraft
1% UW Kraft
Kraft/BCTMP
Note: excluding fluorescent component UW sheets perform better
ConclusionsConclusions
l FWA technology for BCTMP is a technology that works
l Effective at retarding solar/office lighting effects
l Thermal reversion appears not to be an issue