Biodegradable Polycarbonate Synthesis And Properties Of,

Biodegradable polymers are the kind of polymer materials that can be degraded under the action of microbial enzyme or Chemical decomposition. They have wide application potential such as medical and engineering materials fields because of their good biocompatability and degradability. Polylactide and its copolymers, aliphatic polycarbonates and polycaprolactone are the leading members of these polymers, and the aliphatic polycarbonates that synthesized by using CO2 has significance for utilization of reproducible resource.In this paper, aliphatic polycarbonate poly(propylene carbonate maleate) (PPCMA) was successfully synthesized by using a double metal-cyanide catalyst based on Zn3[Co(CN)6]2 as catalyst, which was the terpolymerization of CO2, propylene oxide(PO), and maleic anhydride(MA). And MA was introduced to insert into the backbone of poly(propylene carbonate) as a third monomer. The structure of copolymers were characterized by FT-IR, NMR, WAXD and elemental analysis measurements. And the expected mechanism of copolymerization was proposed. In addition, the degradability of this terpolymer was studied. The results indicated that the terpolymer has better degradability than poly(propylene carbonate) as the introducing of MA unit.Non-isothermal thermal decomposition kinetics of the terpolymer was also studied, and the results revealed the multi-step reaction process and multiple mechanisms for the pyrolysis of the terpolymer. Because of the introducing of MA unit, the terpolymer has a improved thermostability. A new computational method called nonlinear approximation method (NLA) was introduced in this work, and it was an ideal choice for Ea calculation due to its more simple and appropriate analysis process although with a little higher average relative error of Ea compared to other typical model-free methods.PLGA was used as the Wall material and BSA as the drug model to prepare polymer microspheres by the W/O/W multiple emusions method. Effects of drug concentration in inner water and the composition and molecular of PLGA on drug loading abilities were investigated. The results suggested that almost 60% of BSA exist in the surface areas of PLGA, which was the leading cause of burst release. The process conditions need to be improved to abtain the microspheres which has great capability on sustained release.