Polylactide lactic acid

Polylactides are linear polymers obtained from lactic acid, CHjCHOHCOOH, commonly known as poly(lactic acid) or polylactide. Lactic acid occurs naturally in animals and microorganisms and is found in many natural foods especially in fermented foods such as yogurt, buttermilk, sourdough breads, and sauerkraut [90, 91]. Besides being biodegradable, bioresorbable, and biocompatible, PLAs can be easily conformed by conventional thermoplastic melt processing, which makes this class of biodegradable polymers very suitable for uses in bionanocomposites. 

Polylactide is the generaUy accepted term for highly polymeric poly(lactic acid)s. Such polymers are usuaUy produced by polymerization of dilactide the polymerization of lactic acid as such does not produce high molecular weight polymers. The polymers produced from the enantiomeric lactides are highly crystalline, whereas those from the meso lactide are generaUy amorphous. UsuaUy dilactide from L-lactic acid is preferred as a polymerization feedstock because of the avaUabUity of L-lactic acid by fermentation and for the desirable properties of the polymers for various appUcations (1,25). 

Polylactic acid, also known as polylactide, is prepared from the cycHc diester of lactic acid (lactide) by ring-opening addition polymerization, as shown below ... 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

Carboxylic Acids Obtained by Fermentation of Carbohydrates Lactic (2-hydroxy-propionic) acid obtained by fermentation of glucose and polysaccharides is used by NatureWorks (Cargill/Dow LLC) to prepare polylactide (PLA), a biodegradable or recyclable polymer with a potential production of 140000 t a-1 (Scheme 3.4) [23], This and other potential useful reactions from lactic acid have been reviewed by Datta and Henry [24],... 

Polylactide-co-glycolide co-polymers Lactic acid Glycolic acid [15]... 

Lactic acid (CH3-CHOH-COOH) is commonly used as a food additive for flavor and preservation. It is also converted into a polylactide polymer, which represents one of the first commercial applications of... 

Much has been written about Cargill Dow LLC s polylactide (PLA) polymer, also known as NatureWorks PLA. PLA is a thermoplastic produced from biomass sugars by fermentation. The fermentation product, lactic acid, is converted into a lactide that is purified and polymerized using a special ring-opening process (18). 

Polylactide is a degradable polyester, formed by the ring-opening polymerization of lactide or the condensation polymerization of lactic acid. Lactide is produced from lactic acid, which derives from the fermentation of D-glucose, which is usually harvested from high-starch-content crops, such as com or sugar beet (Fig. 1). 

Due to the chiral nature of lactic acid, several distinct forms of polylactide exist poly-L-lactide (PLLA) is the product resulting from polymerization of L,L-lactide (also known as L-lactide). PLLA has a crystallinity around 37%, a glass transition... 

NatureWorks LLC has set up a 300 million plant at Blair, NE, which is capable of producing about 140,000-tons/year of poly-lactide polymers from com sugar. It employs a fermentation process to produce two chiral isomers of lactic acid from glucose, which are then cracked to form three lactide isomers. The isomers are subsequently polymerized to polylactide. 

Polylactides are made from lactic acid and are used for orthopedic repair materials. They can be absorbed by the body and are used for the treatment of porous bone fractures and joint reconstruction. Dextran is a substitute for blood plasma in medicine. It is produced by fermentation of saccharose by Leuconostoc mesenteroides microorganisms. After the fermentation is completed (about 24 h), the cell mass is separated and the dextran is precipitated by addition of ethanol to the liquid phase. 

Polylactides or lactic acid polymers are made from lactic acid, which is in turn made from lactose (or milk sugar) obtained from sugar beet, potatoes, wheat, maize, Polylactides are water resistant and can be formed by injection... 

Some of the com-derived glucose goes into various fermentation processes that lead to other chemical products. For example, large-scale production was recently announced for lactic acid and polylactide plastic derived from it. Citric acid and lysine are two other important fermentation products. 

Plackett D, Andersen TL, Pedersen WB, Nielsen L (2003) Biodegradable composites based on L-polylactide and jute fibres. Compos Sci Technol 63(9) 1287-1296 Sebastien F, Stephane G, Copinet A, Coma V (2006) Novel biodegradable films made from chitosan and poly(lactic acid) with antifungal properties against mycotoxinogen strains. Carbohydr Polym 65(2) 185-193... 

Nearly 95,000 tons of glucose and dextrose are produced by enzymatic liquefaction of starch, mainly tapioca (cassava). Since lactic acid-based biodegradable polymers like polyglycolide and polylactide are not produced in India, consumption of lactic acid is confined to food processing and the pro-... 

In the early 1970s, patents for polylactide/drug mixtures were awarded to DuPont [12, 13]. The first applications for controlled drug delivery involved the release of narcotic antagonists from pLA films [14, 15]. Poly(L(-l-)-lactic acid)... 

The doublet structure of the methyl signal at 17 ppm is caused by the stereochemistry. Polylactides, not yet described in any pharmacopoeias, are rather new biodegradable polyesters derived from the chiral lactic acid and used, e. g., in drug delivery systems. The stereochemistry of the polymer is important to the physical and chemical behavior, especially the polymer properties. Pure tactic polymerization can be differentiated from atactic or mixed polymers by simple comparison of the C NMR spectra (Figure 3-10) [4]. 

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