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Recent Developments on Polylactic acid

Recent Developments on Polylactic acid. Yvon Durant Advanced Polymer Laboratory University of New Hampshire May 31 st , 2006. Leading the way toward greener chemistry. Poly Lactic Acid what can it be used for ? what is it ? What’s the bid deal Research involving PLA @ UNH

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Recent Developments on Polylactic acid

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  1. Recent Developments on Polylactic acid Yvon Durant Advanced Polymer Laboratory University of New Hampshire May 31st, 2006

  2. Leading the way toward greener chemistry Poly Lactic Acid what can it be used for ? what is it ? What’s the bid deal Research involving PLA @ UNH Degradable ties for fishing gear Education software for the commercialization of PLA PLA emulsions Research in renewable polymers

  3. PLA end user products Research in renewable polymers

  4. What can it be used for…. Research in renewable polymers

  5. Corn to PLA Research in renewable polymers

  6. PLA to Lactide LL-Lactide (mp 97 C) LD-Lactide (mp 52 C) L-Lactic Acid DD-Lactide (mp 97C) D-Lactic Acid Research in renewable polymers

  7. Cargill Dow PLA plant Nov 2001 140 KT/Year The Blair project Nebraska Research in renewable polymers

  8. Inventory Analysis Research in renewable polymers

  9. Complete energy analysis Research in renewable polymers

  10. PLA versus other plastics Research in renewable polymers

  11. Process improvements Research in renewable polymers

  12. Potential reduction of greenhouse gasses associated with PLA production Research in renewable polymers

  13. PLA research @ the University of New Hampshire ?

  14. After 15 days, green composite tie, break down and releases float Figure 1: Concept of float for net release after 15 days water exposure Sealine Reducing right whale entanglement Or “how can corn save whales”… Research in renewable polymers

  15. How ? • Develop a composite tie made from a polylactic acid (PLA) polymer matrix that will degrade after a controlled reaction with water. • Ties are being engineered to degrade after 15 days of exposure to seawater at 12C. • Ties will maintain optimal strength until 15 days of exposure has been reached. • Mechanical degradation is activated by a chemical amplification process that release protons, which catalyze the depolymerization of the polyester backbone. Research in renewable polymers

  16. Composite structure Glass fibers PLA-co-GLA matrix Overlapping fibers Microparticle – acid generator Research in renewable polymers

  17. Cascade degradation of PLA WATER • Poly ester can break down through hydrolysis of the ester group Research in renewable polymers

  18. Variables Affecting Degradation Time • Strain • Tg • Molecular weight • Micro-capsule concentration Research in renewable polymers

  19. Before Exposure Affect of Strain on Degradation After Exposure • Ties broke linearly with time according to strain • Max strain extrapolated to be 5kg before exposure to sea water Research in renewable polymers

  20. Degradation results Research in renewable polymers

  21. iComet • iComet is a simulation software that is designed to be used as a training tool for technology managers. • Two or more users or teams create virtual start-up companies to compete in the marketing and development of a new technology.  • Users must take the technology from the early stages of development to a level of high volume production over the course of twenty or more business quarters.  • Users must make strategic managerial decisions in the areas of finance, R&D, marketing, production, and HR in order to compete with the other teams and make their business successful. Research in renewable polymers

  22. Key technology : reduction of energy usage Research in renewable polymers

  23. Multi domain decisions Research in renewable polymers

  24. Finances…. Research in renewable polymers

  25. Results… earning some greens…. Research in renewable polymers

  26. PLA dispersions PLA is a polyester and easily hydrolyzable. It cannot be synthesized in water directly. 2 classic approaches • Bulk polymerization, dissolution in solvent, emulsification, solvent evaporation • Bulk polymerization, dissolution in solvent, precipitation 3 new approaches 1. Bulk polymerization, dissolution in vinyl monomer, mini-emulsification, polymerization 2. Macromonomer, mini-emulsification, polymerization • Polymerization in non-protique solvent, phase transfer Research in renewable polymers

  27. Bulk recipes Research in renewable polymers

  28. Classic Approach 1: Solvent Evaporation • Dissolve PLA in solvent • Miniemulsion in water stabilized with polyvinyl alcohol (PVA) • Evaporate solvent via steam distillation • GC/MS to quantify residual solvent Solvents: CH2Cl2 t-butyl methyl ether isobutyl methyl ether Steam distillation apparatus

  29. Classic Approach 2: precipitation Dissolve PLA in THF –0.1 to 0.5 wt.% Add to water/SDS dropwise through thin gauge needle under mechanical stirring Results: PLA dispersions (100-250nm) Very low productivity Research in renewable polymers

  30. PLA magnetite Research in renewable polymers

  31. New approaches Research in renewable polymers

  32. New Approach 1: PLA/MMA/BA composite • High MW PLA synthesis (70Kg/mole) • DL-lactide • Initiator: hexanol, Catalyst: SnOct2 • Reacted in oven heated to 150oC for 2hrs • Miniemulsion Polymerization • Dissolve PLA in MMA and BA in 1:1:1 ratio • Magnetic stirring  macro-emulsion • 4pphm SDS • Ultrasonicated  miniemulsion • Reacted in 3 neck jacketed reactor at 70oC for 3hrs with magnetic stirring and N2 feed • Initiator: 0.3 g/L KPS Research in renewable polymers

  33. Results for composites • RESULTS: • 47% conversion • solids clumped around magnetic stirrer • likely to be PLA • NMR results showed less PLA, more acrylates in dry latex than in recipe Research in renewable polymers

  34. New approach 2: HEMA-PLA/PS branch • Low MW HEMA-PLA macro-monomer synthesis (5k) • DL-lactide • Initiator: HEMA, Catalyst: SnOct2 • Reacted in oven heated to 150oC for 2hrs • Miniemulsion Polymerization • HEMA-PLA in minimal styrene • Magnetic stirring  macro-emulsion • Aqueous phosphate buffer solution • 4pphm SDS • Ultrasonicated  miniemulsion • Reacted in 3 neck jacketed reactor at 80oC for 3hrs with mechanical stirring and N2 feed • Initiator: 1 wt% KPS Research in renewable polymers

  35. New approach 2: HEMA-PLA/PS branch • RESULTS: • 22.4% conversion, 11% solids • Tg 34oC dried latex • NMR showed 1:4 ratio of PS to PLA, recipe gives 1:1 ratio • Solid chunks in bottom of reactor Research in renewable polymers

  36. New approach 3: HEMA-PLA homopolymer • Low MW HEMA-PLA macro-monomer synthesis • DL-lactide • Initiator: HEMA, Catalyst: SnOct2 • Reacted in oven heated to 150oC for 2hrs • Miniemulsion Polymerization • Heat HEMA-PLA until flows, add water • Magnetic stirring  macro-emulsion • Aqueous phosphate buffer solution • 4pphm SDS • Ultrasonicated  miniemulsion • Reacted in 3 neck jacketed reactor at 80oC for 3hrs with mechanical stirring and N2 • Initiator: 1 wt% KPS Research in renewable polymers

  37. Polymerization monitoring by DSC • Polymerization of HEMA-PLA with BPO • Alternating 80C isothermals – Temperature scans Research in renewable polymers

  38. New approach 3: HEMA-PLA homopolymer • Challenges • Stability • Viscosity of HEMA-PLA • Low Tg of PLA • Cross esterification of HEMA-PLA branches • Degredation of HEMA-PLA while ultrasonicating with added heat Research in renewable polymers

  39. New approach 3: Dispersion Polymerization and Phase Transfer Polymerization: Heat lactide dispersion to 150oC in dispersion media - 3 neck RBF - submerged in oil bath, covered with tinfoil - Ultra turrax: 19.0 min-1 Add initiator (SnOct2 or mPEG), react 2hrs Ultra turrax until cool: < 100oC Phase Transfer: Add water, 1:1 with organic phase Stop ultra turrax, wait for phase separation Separatory funnel to remove organic phase Research in renewable polymers

  40. Approach 3: Dispersion Polymerization and Phase Transfer • Dodecane:Dr = 0.4 • Trial 1: stablilzed with PEG diasterate, transferred to EG, phase separated • Trial 2: stablilzed with PVOH, transferred to water, did not phase separate • Silicone Oil: Stabilized with PEG diasterate • Poly phenyl methyl siloxane Dr = 0 - most of lactide recrystallized, not able to centrifuge into water • Poly-3,3,3-trifluoro propyl methyl siloxane Dr = (0.2) - appeared to be stable, congealed when cooled • PEG dimethyl ether:Stabilized with mPEG, very stable, 20nm nanoparticles, try increasing solids, increasing initiator percentage to vary size Research in renewable polymers

  41. Acknowledgements • Shelley Dougherty • Romuald Couronne • Funding : • University of New Hampshire (iComet) • National Ocean and Atmosphere Agency (whale entanglement) • New England Green Chemistry Consortium (novel PLA dispersions) Research in renewable polymers

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