recycling pla through reactive extrusion - itr2016/media/itr2014/2014/... · helping innovators...

Helping Innovators Innovate

Recycling PLA Through Reactive Extrusion

Dr. Adam R. PawloskiTechnical Director

Coauthors and Contributors: Zachary Oberholtzer*, Aaron Hedegaard**, Dr. Chris Macosko**, Dr. Paul Fowler***, Garrett Van Gorden, Adam E.

Szymanski, Brandon J. Cernohous, Gregg S. Bennett, Jeffery J. Cernohous

*Bucknell University, **University of Minnesota, ***Wisconsin Institute for Sustainable Technology, UWSP

Innovation Takes Root, February 2014


Presentation Overview• Brief overview of Interfacial Solutions

• Hyperbranching of Polylactic Acid (PLA) and deTerra® Biobased Polymers

• Bringing Down the Cost of PLA Compounds Hyperbranched PLA as a Melt Strength Additive Recycled PLA Feedstocks

• Hyperbranching of Post-Industrial and Post-Consumer PLA


Interfacial Solutions is a leading and independent provider of R&D services to theplastics industry with a proven track record of helping innovators innovate. Ourcreative team of scientists possess more than 50 patents and are equipped withstate-of-the-art polymer testing equipment, compound and processing equipment,and production capabilities to meet a broad range of plastic industry challenges.Headquarters: River Falls, WI (45 minutes from Minneapolis, MN)Founded: 2003Employees: ~40 (14 Technical Degrees, 3 Ph.Ds)Facilities: ~65,000 sq. ft.Website: www.interfacialsolutions.com


Hyperbranching of Polylactic Acid

• The melt strength of linear PLA is much lower than olefins and other common plastics• Affects curtain width, profile

shape, foaming, etc.• Implications on flammability

performance and impact resistance

• Branched polymers have fundamentally different rheology than linear polymers

NatureWorks 2003D PLA Extruded at 180oC through an 18” Wide Cast Film Die


Linear PLA Polymer

Chain Extended Polymer(PLA + chain extender by

reactive extrusion)

Linear and Chain Extended PLA

Ex: CESA-Extend, Joncryl, other epoxides


Hyperbranched PLA(PLA + IFS Proprietary Chemistry by Reactive

Extrusion)

Hyperbranching of PLA

• The basis for IFS deTerra® bio-based polymers→Greatly improved melt strength and processing→Unique rheology→Enables improved compounds, including flame

retardant grades


NatureWorks 2003D PLA Low Level of Branching High Level of Branching

Unmodified PLA

Low Level Branching

High Level Branching• Linear PLA has poor melt

strength• Chain branching

increases melt strength and stabilizes the extrusion curtain

Melt Strength


• Hyperbranched PLA is more robust to moisture than linear PLA

• Superior melt strength even when wet• HBPLA can be processed in many

applications without drying• MFI less sensitive to moisture content

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

MFI

(g/10 min)

% H2O

MFI vs % H2O

2003D PLA

XP759

Moisture

0.15% H2O0.05% H2O

Free Falling Extrudate

Virg

in

Rec

ycle

d

Virg

in-H

yper

bran

ched

Rec

ycle

d-H

yper

bran

ched


Unique Rheology of Hyperbranched PLA

• Small amplitude oscillatory shear rheometry (180oC)• Chain extended and hyperbranched materials show

similar increase in modulus (stiffer melt)• Chain extended materials continue to react

Data provided by University of Minnesota (Macosko Group)



• Capillary rheometry extensional viscosity at high extension rates

• Mimics extrusion processing conditions

• Shear viscosity of hyperbranched PLA is less than that of chain extended PLA

• Hyperbranched PLA will exhibit advantage in reduced extruder torque and die pressure Data provided by University of

Minnesota (Macosko Group)



• Hyperbranched PLA is the only PLA to exhibit strain hardening behavior as determined by extensional viscosity

• Advantage for foams to prevent cell collapse

Data provided by University of Minnesota (Macosko Group)


deTerra® Biobased Polymer Property Summary

Grade Biobased Content

(%)

Specific Gravity

Flexural Modulus

(psi)

Flexural Strength

(psi)

Notched Izod Impact

Strength (ft-lbs/in)

Melt Flow Index (g/10 min @

190C, 2.12 Kg)

Flammability Ratings

PR146 93 1.25 550,000 12,000 0.8 1.0 V2, 24% LOI, E84: 0 Flame Spread, <70 Smoke Index

XP345 76 1.30 600,000 11,200 0.95 18.0 V0, 28% LOI

XP698 85 1.25 380,000 8,600 16.5 28.0 NA

XP696 93 1.26 520,000 12,600 1.2 1.0 V2, 23% LOI

XP752 99 1.24 450,000 17,000 1.2 11.0 NA

Ingeo 2003D

100 1.24 450,000 14,000 0.3 7 NA, 22% LOI

• Commercialized compounds under the deTerra® product name taking advantage of hyperbranching chemistry

• Performance at extremely high biobased content


Target Economics

0

0.5

1

1.5

2

2.5

deTerraPR146

PVC PETG ExperimentaldeTerra A

ExperimentaldeTerra B

Rel

ativ

e P

rice

• Cost is a primary barrier for adoption of sustainable solutions


Bringing Down the Cost of PLA Compounds

• Two approaches to reduce PLA compound costs for customers

• Use less make hyperbranched PLA an additive for improving melt strength

• Incorporate recycled PLA (post-industrial or post-consumer)


Hyperbranched PLA as an Additive

• As an additive, hyperbranched PLA can be added to linear PLA and compounds to increase melt strength• Non-reactive strategy• 10 to >50wt% addition levels effective

100% Recycled PLA100% Virgin 2003D PLA

50% Recycled PLA50% XP769

50% 2003D PLA50% XP769



• More is better for improving processability, but addition levels of 10 to 50% can be effective in many processes


Resin

MFI (g/10min,

190oC, 2.16kg)

Tensile Strength

(psi)

Tensile Modulus

(psi)

Tensile Elongation

(%)

Notched Izod Impact

Strength (ft-lb/in)

Unnotched Izod Impact Strength (ft-

lb/in)Virgin PLA (NatureWorks 2003D) 6.0 8600 511000 2.1 0.61 4.2XP759 2.7 9100 492000 2.3 0.57 5.55% Hyperbranched PLA Additive 6.2 8070 479000 2.0 0.54 4.420% Hyperbranched PLA Additive 3.9 8370 485000 2.0 0.55 4.5


• Modified PLA resins with high levels of hyperbranching can be let down into standard PLA resins to improve processability

• Retains good mechanical properties and increases processability


Recycling PLA (or Other Bioplastics)• PLA is recyclable, but recycled with hyperbranching

creates improved performance• Increasing the amount of recycled PLA will further improve

PLA’s sustainability message• Many product applications seek biobased content over

compostability→Compostability standards are challenging for durables→Composters don’t want the bioplastic

• Only limited recycling of PLA→Drying required to reduce loss of MW by hydrolysis→Post-Consumer waste goes into mixed plastics and is

not recycled→Much goes into landfill


Recycling PLA

Old$Paradigm:$$Due$to$a$lack$of$widespread$PLA$recycling$or$industrial$compos9ng,$most$PLA$ends$up$in$landfill$

New$Paradigm:$$Complete$the$loop$from$product$to$$ $$$$$$$$scrap$to$product$by$PLA$recycling$

Green%Products% Green%Scrap% Green%Product%

Green%Products% Green%Landfill%


Recycling PLA• Is there enough?

• Global bioplastics market of ~850K MT ($1.8B)• PLA is about 50% of the market by volume ($0.5B)• Growing at >20% CAGR• Most applications in Packaging and Fiber

“Global Bio-Based Plastics Market Study”, Frost and Sullivan, Dec. 2009, pg 4-7.

• Yes, there is enough, but spread out and challenging to get

• Sufficient Post-Industrial scrap exists today in US to start interest


Post%Industrial.PLA.

Post%Consumer.PLA. Interfacial.

Solu7ons’.Proprietary.

Hyperbranching.Technology.

Sale.of.Recycled.PLA.

Resins.

Plas7cs.Processors.

Consumer.Products.

Recycling PLA

• Convert PLA (or other bioplastic) scrap into a hyperbranched, performance resin

• Feedstocks range widely from $0.15 to $0.80/lb depending on quality• Sale of resin to plastics processors or license technology for in-house

compounding• Durables applications are emerging and make the most sense for

introduction of recycled PLA content


Recycling PLA By Hyperbranching• IFS hyperbranching technology upgrades scrap PLA to better-

than-virgin properties• Prestigious NSF SBIR Phase I award granted in July 2012 and

Phase II granted in September 2013Hyperbranching with Virgin PLA Hyperbranching with Post-Industrial PLA

Starting Resin

Increasing Degree of Branching


Post-Industrial PLA Scrap Feedstocks

• 8 post-industrial / 1 post-consumer waste streams evaluated• Widely varying quality

Virgin Ingeo 2003D $0.95 14800 502000 8310 491000 2.02 0.54 5.4 3.7 219907 1.69

Reprocessed and recrystalized 4043D PLA

$0.80 15300 475000 8810 498000 2.21 0.61 5.0 11.8 145331 1.76

Ingeo 2003D PLA, regrind $0.50 6390 502000 4020 523000 0.09 0.50 3.5 420.0 108147 2.12

Ingeo 2003D PLA, mixed regrind from

cardstock$0.50 2630 456000 1380 479000 0.34 0.29 0.8 liquefied 60618 1.51

Recycled Gift Cards, 3/8" regrind $0.30 12200 516000 6520 518000 1.65 0.69 10.2 14.0 145614 1.77

Recycled Water bottles / cups $0.30 15000 490000 8280 502000 2.06 0.50 3.2 6.5 197791 1.78

Recycled Yogurt cups $0.30 12500 440000 6810 436000 2.04 0.48 3.1 5.5 197940 2.00

Reprocessed 85/15 4032D/4060D PLA,

pellets$0.80 15400 497000 8650 514000 2.22 0.75 4.5 28.1 191782 1.89

Melt processed and filtered, pellet $0.78 12800 444000 7370 478000 2.07 1.02 13.0 7.8 156538 1.83

Post Consumer PLA unknown 14500 461000 7830 496000 2.05 0.55 3.8 5.0 187363 1.87

MFI 190oC, 2.16kg

(g/10 min)

Molecular Weight (MWw)

PolydispersityFlexural Modulus

(psi)

Tensile Strenth

(psi)

Tensile Modulus

(psi)

Elongation (%)

Notched Impact

(ft-lbs/in)

Unnotched Impact

(ft-lbs/in)Description

Approx. Volume

Price ($/lb)

Flexural Strength

(psi)


Hyperbranched, Recycled PLAExample of a high quality scrap (reprocessed):

Example of a poor quality scrap:

• Note the steady decrease in MFI, MW increase, and stable mechanicals

• Note the decrease in MFI, MW increase, and improved mechanicals

• Increasing branching would likely improve further

Base resin 8490 513000 2.06 4.4 8.8 145331Gen I, Low INT 8840 493000 2.21 5.0 6.8 141684Gen I, Low CXL 9030 498000 2.27 6.8 3.2 464936Gen I, High CXL 9060 502000 2.27 5.1 1.6 469717Gen I, High INT 9120 498000 2.39 6.8 0.7 495094Gen II, Low INT 7500 498000 1.90 6.1 2.3 306622Gen II, Low CXL 7700 516000 1.85 6.7 0.7 522492Gen II, High CXL 6920 510000 1.96 7.8 1.1 456760Gen II, High INT 7850 516000 2.26 8.6 0.0 407940

Unnotched Impact

(ft-lbs/in)

MFI 190oC, 2.16kg

(g/10 min)

Molecular Weight

RS791, Reprocessed

and recrystalized 4043D PLA

Resin Code DescriptionTensile Strenth

(psi)

Tensile Modulus

(psi)

Elongation (%)

Base resin 1380 479000 0.34 0.8 liquefied 60618Gen I, Low INT - - - - - 67541Gen I, Low CXL 73988Gen I, High CXL 77360Gen I, High INT - - - - - 143156Gen II, Low INT 1500 489000 0.38 1.3 646.5 63338Gen II, Low CXL 766 469000 0.18 0.3 805.7 67586Gen II, High CXL 1090 476000 0.28 0.4 795.2 62884Gen II, High INT 1910 483000 0.44 1.0 400.5 100312

Unnotched Impact

(ft-lbs/in)

MFI 190oC, 2.16kg

(g/10 min)

Molecular Weight

RS793, Ingeo 2003D PLA, mixed

regrind from cardstock

Unsuccessful Processing


(psi)

Tensile Modulus

(psi)

Elongation (%)


Post-Consumer PLA Scrap and Hyperbranching

• Post-consumer PLA collected, sorted, and washed by researchers at the Wisconsin Institute for Sustainable Technology (WIST) at UW Stevens Point (subaward with Prof. Paul Fowler)

• Surprisingly good properties from post-consumer scrap• Contamination from adhesives, paper, inks, etc. not removed• Very effective hyperbranching and good resulting properties

Unnotched MFI 190oC,

(ft-lbs/in) (g/10 min)

Base resin 7830 496000 2.05 3.8 5.0 187363Gen I, Low INT 8490 490000 2.26 4.6 1.1 499303Gen I, Low CXL 8710 490000 2.49 5.8 0.0 501249Gen I, High CXL 8630 503000 2.46 5.0 0.0 482718Gen I, High INT 8560 501000 2.52 6.8 0.0 243738Gen II, Low INT 7930 518000 2.10 5.3 0.8 397662Gen II, Low CXL 8420 535000 2.18 6.2 0.3 518328Gen II, High CXL 7670 510000 2.04 5.9 0.3 521551Gen II, High INT 8500 507000 2.42 7.3 0.0 214583

Tensile Modulus

(psi)

Elongation (%)

Molecular Weight, MWw

RS881, Post Consumer WIST PLA


(psi)


Hyperbranched, Recycled PLA

• Tuning the chemistry and process conditions for reactive extrusion can “dial-in” the properties of the hyperbranched, recycled product

ResinMFI (g/10min, 190oC, 2.16kg) Mw (kg/mol)

Flexural Strength (kpsi)

Virgin PLA (NatureWorks 2003D) 6.0 220 155Hyperbranched, virgin PLA (XP759) 2.7 425 156Prime Grade Post-industrial PLA 11.8 145 153Low level hyperbranching 6.8 142 153Intermediate level hyperbranching 3.2 464 155High level hyperbranching 1.6 470 155Low Grade Post-Industrial PLA 420.0 108 64Low level hyperbranching 285.0 125 98Intermediate level hyperbranching 290.0 145 122High level hyperbranching 130.0 300 135Post-Consumer PLA 5.0 187 145Low level hyperbranching 0.8 398 141Intermediate level hyperbranching 0.3 518 145High level hyperbranching 0.0 --- 149


Conclusion• Interfacial Solutions’ proprietary hyperbranching

technology can dramatically improve the quality of virgin and recycled PLA resins

• deTerra® compounds based on hyperbranched, recycled PLA are on the market with initial commercial sales

• Costs for PLA compounds can be reduced by using deTerra grades as additives and incorporating recycled feedstocks

• Further improvements in performance and cost are under development


Acknowledgements• This material is based in part upon work supported by the National

Science Foundation under Grant No. IIP-1215292

• Disclaimer: Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Thank You!

Interfacial Solutions, LLC949 Antler Ct.

River Falls, WI 54022(715) 425-7957

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