Study On The Synthesis Of Star Biodegradable Polymer

The application research progress and synthesis methods of star polymers werereviewed in this paper. And series of biodegradable star polymers of new materialswere designed and prepared. Molecular assembling and tailoring were adopted onpolyester polyether poly (amino acid) materials by selecting nucleus molecule withdifferent functionalities in the synthesized new materials, thus new star polymers withtunable properties according to their use were build and synthesized. Selected nucleuswere glycerol, pentaerythritol,4-arm-Polyethylene glycol,2-amino-1,3-propanedioland lysine.3-block-3-arm and3-block-4-arm star polymers of polyester materials weresynthesized, and the mainly innovation point embodies in the synthesis of the blockpolymers of star biodegradable materials by step-by-step methods, and3-arm,4-armstar random polymers were synthesized by one-pot reaction. Polymers of specificmolecular weight synthesized through step-by-step was regular. When feeding in themolar ratio of1:30,1:40, the molecular weight increased about15,000Da in the firststep,5000Da in the second step, and1000Da in the third step.Star biodegradable materials consist of polyether and polyester were obtained byring opening polymerization of4-arm-Polyethylene glycol and lactone monomer.And the mainly innovation point embodies in the hydrophilcityies of synthesized4-arm-star-polyether-polyester polymers increased obviously compared to polyestermaterials. Copolymers of low molecular weight changed from crystal material toamorphous substance after the introduction of TMC. The microscopic view andassembly form were divers in different solvent. Polymers appear as uniform solidsphere shape in toluene.The copolymers consist of polyester and polyamino acid synthesized by twice ringopening polymerization selected serinol as nucleus, thus polyamino acid structure canbe attached on polyesters. The properties of the copolymers conform with polyaminoacid in thermodynamic aspects, and have secondary helical structure like polyamino acid and is a unique new star polymers, the intensity and the melting temperaturewere increased at the same time compared with polyesters, but the solubility wasdecreased.Selected lysine as nucleus, the polyether chain was connected on lysine bycondensation reaction, and then the introduction of polyester chain by ring openingreaction of lactone initiated by amino group, adopt the same strategy, polyamino acidchain was introduced by ring opening reaction of nitrogen acid anhydride initiated byamino group, consequently, the hetero arm star polymers of ABC shape polyetherpolyester polyamino acid were formed. The melting temperature were basically thesame after the combination of polyether with polyester, but melting absorption peakbecame weak after the introduction of polyamino acid, and mainly show theproperties of polyamino acid.