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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
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
Linear PLA Polymer
Chain Extended Polymer(PLA + chain extender by
reactive extrusion)
Linear and Chain Extended PLA
Ex: CESA-Extend, Joncryl, other epoxides
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
• 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
Helping Innovators Innovate
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)
Helping Innovators Innovate
Unique Rheology of Hyperbranched PLA
• 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)
Helping Innovators Innovate
Unique Rheology of Hyperbranched PLA
• 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)
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
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)
Helping Innovators Innovate
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
Helping Innovators Innovate
Hyperbranched PLA as an Additive
• More is better for improving processability, but addition levels of 10 to 50% can be effective in many processes
Helping Innovators Innovate
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
Hyperbranched PLA as an Additive
• 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
Helping Innovators Innovate
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
Helping Innovators Innovate
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%
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
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)
Helping Innovators Innovate
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
Resin Code DescriptionTensile Strenth
(psi)
Tensile Modulus
(psi)
Elongation (%)
Helping Innovators Innovate
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
Resin Code DescriptionTensile Strenth
(psi)
Helping Innovators Innovate
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
Helping Innovators Innovate
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
Helping Innovators Innovate
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