A literature review is presented regarding the synthesis, and physicochemical, chemical, and mechanical properties of poly(lactic acid)(PLA). Poly(lactic acid) exists as a polymeric helix, with an orthorhombic unit cell. The tensile properties of PLA can vary widely, depending on whether or not it is annealed or oriented or what its degree of crystallinity is. Also discussed are the effects of processing on PLA. Crystallization and crystallization kinetics of PLA are also investigated. Solution and melt rheology of PLA is also discussed. Four different power-law equations and 14 different Mark–Houwink equations are presented for PLA. Nuclear magnetic resonance, UV–VIS, and FTIR spectroscopy of PLA are briefly discussed. Finally, research conducted on starch–PLA composites is introduced.

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A Literature Review of Poly(Lactic Acid)

4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

Transformation of carbon dioxide.

Polylactic acid is proving to be a viable alternative to petrochemical-based plastics for many applications It is produced from renewable resources and is biodegradable, decomposing to give H2O, CO2, and humus, the black material in soil In addition, it has unique physical properties that make it useful in diverse applications including paper coating, fibers, films, and packaging (see Figure)

Polylactic Acid Technology

s, and 360 patents, and edited 12 books. He has also received over 80 major awards including the Gairdner Foundation International Award, Lemelson-MIT prize, ACS’s Applied Polymer Science and Polymer Chemistry Awards, AICHE’s Professional Progress, Bioengineering, Walker and Stine Materials Science and Engineering Awards. In 1989, Dr. Langer was elected to the Institute of Medicine of the National Academy of Sciences, and in 1992 he was elected to both the National Academy of Engineering and the National Academy of Sciences. He is the only active member of all three National Academies. Kevin Shakesheff was born in Ashington, Northumberland, U.K., in 1969. He received his Bacheclor of Pharmacy degree from the University of Nottingham in 1991 and a Ph.D. from the same institution in 1995. In 1996 he became a NATO Postdoctoral Fellow at MIT, Department of Chemical Engineering. He is currently an EPSRC Advanced Fellow at the School of Pharmaceutical Sciences, The University of Nottingham. His research group investigates new methods of engineering polymer surfaces and the application of these engineered materials in drug delivery and tissue engineering. 3182 Chemical Reviews, 1999, Vol. 99, No. 11 Uhrich et al.

Polymeric Systems for Controlled Drug Release

RGD modified polymers: biomaterials for stimulated cell adhesion and beyond

The blue colored complex between poly(vinyl alcohol) (PVA) and iodine was prepared at 5°C by mixing an aqueous solution of PVA with an aqueous ethanolic solution of iodine containing boric acid. The absorption spectrum of the system shows bands at 226 nm (A), 290 nm (B), 355 nm (C), and 650 nm (D). Their relative absorbances change largely depending on temperature. When the system is gradually warmed, the chromophoric band D decays and the intensity of band A increases. By lowering the temperature again to 5°C the concentration of chromophore increases. It was found that the decay and the re-formation of the chromophore are reversible in the temperature range 5 to 15°C. Above 15°C, contrarily, hysteresis effects are encountered for the re-formation. Thus, when the chromophore is re-formed at 5°C, the spectra shows an isosbestic point at 420 nm, between bands C and D. The dependence on temperature of bands B and C is quite independent from each other, which strongly indicates that the latter band should be assigned to another iodide species than the I−3 ion (band B) and the I− ion (band A). Based on these experimental data a new mechanism is proposed involving the complex ion I−3 · I2 which is supposed to be a precursor of the chromophoric pentaiodide ion I5−.

A peculiar temperature‐dependent behavior of iodine species at the formation of chromophore between iodine and aqueous poly(vinyl alcohol)

Polymerization via Zwitterion. 9. Alternating Copolymerizations of 2-Phenyl-1,3,2-dioxaphospholane with Electrophilic Monomers of Acrylic Acid, β-Propiolactone, and Acrylamide

Polymerization via Betaine. V. Alternating Copolymerization of 1,3,3-Trimethylazetidine with Acrylic Acid. A Novel Method for the Preparation of Amine-Ester Type Polymer

Yoshiharu Kimura

Papers

A peculiar temperature‐dependent behavior of iodine species at the formation of chromophore between iodine and aqueous poly(vinyl alcohol)

Polymerization via Zwitterion. 9. Alternating Copolymerizations of 2-Phenyl-1,3,2-dioxaphospholane with Electrophilic Monomers of Acrylic Acid, β-Propiolactone, and Acrylamide

Polymerization via Betaine. V. Alternating Copolymerization of 1,3,3-Trimethylazetidine with Acrylic Acid. A Novel Method for the Preparation of Amine-Ester Type Polymer

Synthesis and properties of novel thermosetting polysiloxane-block-polyimides with vinyl functionality

Characterization of polysiloxane-block-polyimides with silicate group in the polysiloxane segments