L-Lactide copolymers

SCHEME 8.8 Synthesis of statistical poly(trimethylene carbonate-co-D,L-lactide) copolymers. 

TABLE 2. Physical Properties of Selected Poly(7V-vinyl-2-pyrrolidone)-A-poly-(D,L-lactide) Copolymers Prepared According to the Current Invention... 

Tsuji, H., Tezuka, Y., Saha, S.K. et al. (2005) Spherulite growth of L-lactide copolymers effects of tacticity and comonomers. Polymer, 46, 4917-4927. 

Penning, J.P., Dijkstra, H. and Pennings, A.J. (1993) Preparation and properties of absorbable fibers from L-lactide copolymers. Polymer, 34,942-951. 

Saha, S.K. and Tsuji, H. (2006) Hydrolytic degradation of amorphous-made films of L-lactide copolymers with gJycoUde and D-lactide. Macromolecular Materials and Engineering, 291,357-368. 

Hu, D. S. G., and H. J. Liu, Structural analysis and degradation behavior in polyethylene-glycol poly (L-lactide) copolymers, Journal of Applied Polymer Science, 51(3) 473-482 (1994). 

Glycolide L-lactide copolymers Lactide trimethylene carbonate copolymers Lactide tetramethylglycolide copolymers Lactide a-valerolactone copolymers Methacrylate N-vinyl-pyrrolidone copolymers Lactic acid ethylene oxide copolymers... 

The properties of PLA, as indeed those of other polymers, depend on its molecular characteristics, as well as on the presence of ordered structures, such as crystalline thickness, crystallinity, spherulite size, morphology and degree of chain orientation. The physical properties of polylactide are related to the enantiomeric purity of the lactic acid stereo-copolymers. Homo-PLA is a linear macromolecule with a molecular architecture that is determined by its stereochemical composition. PLA can be produced in a totally amorphous or with up to 40 per cent crystalline. PLA resins containing more than 93 per cent of L-lactic acid are semi-crystalline, but, when it contains 50-93 per cent of it, it is entirely amorphous. Both meso- and D-lactides induce twists in the very regular PLLA architecture. Macromolecular imperfections are responsible for the decrease in both the rate and the extent of PLLA crystallization. In practise, most PLAs are made up of L-and D,L-lactide copolymers, since the reaction media often contain some meso-lactide iir turities. 

Focarete M.L., Scandola M., Dobrzynski R, Kowalczuk M., MiscihUity and mechanical properties of blends of (L)-lactide copolymers with atactic poly(3-hydroxybutyrate). Macromolecules, 35, 2002, 8472-8477. 

The PDLA, PLLA or high d- or L-lactide copolymers have regular structures. The polylactides are either amorphous or semicrystalline at room temperature, depending on the molecular weight and content of l, d or meso-lactide in the main chain. PLA can be totally amorphous or up to 40% crystalline. PLA resins containing more than 93% L-lactic acid can crystallize. However, high molecular weight can reduce the crystallization rate, and therefore the... 

Poly(glycolide-co-L-lactide) copolymer (Vicryl , Vicryl Rapide , and Polysorb )... 

Ethicon introduced a similar glycolide-L-lactide copolymer suture in the late 1990s Panacryl. They basically reversed the molar ratio of glycohde to L-lactide, 5/95 molar ratio of glycolide to L-lactide. As a result of the predominant L-lactide component in Panacryl suture, its absorption behaves... 

Poly(glycolide/L-lactide) copolymer at 90% glycolide and 10% L-lactide Polyglactin 910 Coated vicryl Braided or monofilament... 

Scanning electron images of some commercial absorbable sutures (a) Chromic catgut polyglycolic acid family (b) Dexon poly(glycolide/L-lactide) copolymer or polyglactin 910 family ... 

Hu, D., and Liu, H., 1994, Structural analysis and degradation behaviour in polyethylene glycol/poly(L-lactide) copolymers, J. Appl Polym. Set 51 473-482. 

Pego, A.P., Poot, A.A., Grijpma, D.W., Feijen, J., 2003a. Physical properties of high molecular weight 1,3-trimethylene carbonate and D,L-lactide copolymers. J. Mater. Sci. Mater. Med. 14 (9), 767-773. 

Bioresorbable linear aliphatic polyesters (e.g., polyglycolide, polylactide, polycaprolactone, polyhydroxybutyrate) and their copolymers within the aliphatic polyester family like poly(glycolide-L-lactide) copolymer and poly(glycolide-E-caprolactone) copolymer. 

Table 3 Thermal decomposition of PDL/L-lactide copolymers synthesized by Novozyme 35/organometallk catalyst qrstem...

Maquet,V., Martin, D., Scholtes, F., Franzen, R., Schoenen, J., Moonen, G., and Jerme, R., Poly(n,L-lactide) foams modified by poly(ethylene oxide)-block-poly(D,L-lactide) copolymers and a-FGF in vitro and in vivo evaluation for spinal cord regeneration. Biomaterials 22,1137-1146,2001. 

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