Polyglycolic Acids And Rosin Modified Phenolic Resin

Polyhydroxylated acid, the biodegradable polyester, was new-type performance macromolecule material that had been widely used in medicine and surgical operation because of its biocomposability and biocompatibility. At present, the developed polyester had polyhydroxybutyrate(PHB) polycaprolactone(PCL) -. polyglycolic acid(PHB) -. polylatide acid(PLA) and thek copolymer, and so on. In a new> one-step synthesis, polyglycolic acid was firstly prepared by the reaction of chloroacetic acid with triethylamine hi solvent. In addition, the indirect method was used to synthesize polylactide acid, that is to say, lactide-the six-membered cyclic dimer was prepared with lactic acid, and polylactide acid was obtained by the ring-opening bulk polymerization of lactide when stannous octoate was used as the initiator.At the synthetic process of polygylcolic acid, it was described that effects of the different solvents and bases on the polymerization, chloroform and ether was found to be the efficacious solvents when chloroacetic acid reacted with triethylamine, and the overall yield of reaction was 89.1% under suitable conditions, the melting point of polyglycolic acid was 216-218癈 by washing with ethanol and water.First of all, in the process of the synthesis of polylactic acid by the indirect method, zinc oxide was used as a catalyst. Then the low molecular weight polylactic acid was obtained from direct condensation of lactic acid in the normal pressure. Furthermore it was compressed to prepare lactide in the high temperature. The reaction time was shortened by improving the reaction conditions, and the melting point of lactide reach 118-120 by recrystalling the impure monomer with toluene. Secondly, the ring opening polymerization of lactide was carried out in the bulk by initiating with stannous octoate.