Synthesis of Poly Lactic Acid

Figure 13.1.4 The synthesis of poly(lactic acid) (PLA) by a ring-opening polymerization of the cyclic diester of lactic acid (lactide).

Mehta, R., Kumar, V, Bhunia, H. and Upadhyay, S.N. (2(X)5) Synthesis of poly(lactic acid) A review. Journal cf Macromolecular Science-Polymer Reviews, 45,325-349. 

Mehta R, Kumar V, Bhunia H, Upadhyay SN. Synthesis of poly(lactic acid) a review. J Macromol Science-Polymer Rev 2005 C45(4) 325—49. 

Figure 12.2 Ring-opening polymerization for the synthesis of poly(lactic acid).

Scheme 2.3 Synthesis of poly(lactic) acid or polylactic acid.

Similar to the synthesis of poly(lactic acid), the polycondensation of glycolic add is the simplest process available to prepare PGA but it is not the most efficient one because it yidds low-molecular-wdght products. The procediue is as follows glycolic add is heated at atmospheric pressiue and a temperature of about 175-185 C during a time necessary for removing water. Subsequently, the reaction pressure is reduced... 

Feng Y, Klee D, Hocker H (2002b), Synthesis of poly[(lactic acid)-a/t- or co-((s )-aspartic acid)] from (35, 6R,5)-3-[(benzyloxycarbonyl)methyl]-6-methylmorpholine-2,5-dione , Macromol. Chem. Phys., 203 (5-6), 819-824. 

Additives An advantage of organocatalytic ROP of lactide is that the synthesis is not oxygen sensitive. However, the reagents and solvents have to be extremely dry, since every water molecule initiates and deactivates/reacts with the catalysts, e.g. the strong bases. The initiation of poly(lactic acid) homopolymer by water is especially unwanted when polymerizing well-defined copolymers using a macroinitiator. Acids such as benzoic acid are used for a rapid termination of the polymerization. Chloroform and dichloromethane are commonly used as solvents, since lactide is easily dissolved in these solvents. Chloroform stabilized with amylenes rather than with ethanol should be used. 

FIGURE 1.15 Synthesis of poly(lactic-co-glycolic acid). 

Albertsson, A.-C., Varma, I.K., Lochab, B. et al. (2010) Design and synthesis of different types of poly(lactic acid), in Poly(Lactic Acid) Synthesis, Structures, Properties, Processing, and Applications (Wiley Series on Polymer Engineering and Technology) (eds R. Auras, L.-T. Lim, S.E.M. Selke and H. Tsuji), John WUey Sons, Inc., NJ, pp. 43-58. 

The most common matrix materials for drug delivery are polymers. The field of biodegradable polymers has developed rapidly since the synthesis and biodegradability of poly(lactic acid) (PLA) was reported already in 1966 (7). Natural polymers used for drug delivery have been reviewed (8). 

DESIGN AND SYNTHESIS OF DIFFERENT TYPES OF POLY(LACTIC ACID)... 

Synthesis and Production of Poly(lactic Acid) Table 2.1 Physical Properties of Lactic Acid... 

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