The Biodegradable Materials Of Poly (Hydroxyalkanoate)

Polyhydroxyalknoates which include polylactide, polyglycolide, polycaprolactone poly-3-hydroxybutyrate and their copolymers are polymer materials that can be degraded by organisms and have good biocompatibility. Since the polymer materials have no toxicity and can be absorbed, greater and greater attention has been paid to the related researches and development, and they are increasingly applied in various areas, especially medicine and pharmacy, such as drug release system, resorbable surgical sutures, orthopaedics fixation materials and organize restore materials.The purpose of this paper is to prepare surface coating of cardiovascular stent. The request of a surface coating of cardiovascular stent is that it can be degraded and has no toxicity, good mechanism property and good biocompatibility with human. The cardiovascular stent can be expanded in the human blood vessel to treat vessel straitness. The new coating material can solve the problem that vessel re-straitness.The experiments include polymerization and degradation. The polymerization experiment study the effect of polymerization conditions to productions, the degradation experiment study degradation disciplinarian of different samples.The raw materials in this paper include DL-lactic acid, L- lactic acid, glycollic acid, e-caprolactone, p- butyrolactone.Lactide and glycolide were synthesized from lactic acid and glycolic acid respectively, after all monomer rarefied, a set of homopolymerizations and copolymerizations of lactide with stannous octoate and e- caprolactone with stannous octoate and β- butyrolactone with distannoxane as an initiator were carried out. A series of polymers of PLLA, PDLA, PCL, PHB, PLLGA, PDLGA, PCDLA, PCLLA, PBLLA, PBDLA and PBCL were gained. This paper focuses on the effects of initiator concentration, polymerization time and temperature on the polymers characters, which were measured by GPC, DSC, FT-IR, and NMR.A series of PLGA, PLLA and PDLA were prepared by the ring opening polymerization process.The every resulting sample was made into the same standard films, and then put them in Hank's solution to observe their weight loss, molecular weight and compose proportion respectively. The sample of 7:3 PLGA is an appropriate material for coating of cardiovascular stent. it also is a theory preparing of drug slow-released dynamics.