Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for prepa...Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for preparing degradable polyester elastomers.By using cyclic trimeric phosphazene base(CTPB)as an organocatalyst,we succesfully synthesized PMs with different molecular weights(8.2 kDa to 100.7 kDa)in high yields via ring-opening polymerization(ROP)of menthide.When a CTPB/urea binary catalytic system was adopted,the polymerizations proceeded in a more controlled manner.Using glycerol as initiator,star shaped PMs with well.defined structure were synthesized and subsequently end-capped by acrylate.UV iradiation of the terminal acrylate groups in the star-shaped PMs resulted in formation of chemically cos-linked polyester elastomers without heat or other stimuli.The obtained polyester elastomers exhibit matched modulus(3.8-5.5 MPa),tensile strength(0.56-0.68 MPa),and strain at break(280%-320%)with soft body tssues,displaying great potential in biomedical applications.展开更多
The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chrom...The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.21704048)the 111 Project(No.D17004)the Taishan Scholars Constructive Engineering Foundation(No.tsqn20161031).
文摘Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for preparing degradable polyester elastomers.By using cyclic trimeric phosphazene base(CTPB)as an organocatalyst,we succesfully synthesized PMs with different molecular weights(8.2 kDa to 100.7 kDa)in high yields via ring-opening polymerization(ROP)of menthide.When a CTPB/urea binary catalytic system was adopted,the polymerizations proceeded in a more controlled manner.Using glycerol as initiator,star shaped PMs with well.defined structure were synthesized and subsequently end-capped by acrylate.UV iradiation of the terminal acrylate groups in the star-shaped PMs resulted in formation of chemically cos-linked polyester elastomers without heat or other stimuli.The obtained polyester elastomers exhibit matched modulus(3.8-5.5 MPa),tensile strength(0.56-0.68 MPa),and strain at break(280%-320%)with soft body tssues,displaying great potential in biomedical applications.
基金finanically supported by the National Natural Science Foundation of China (No. 21474010)the Priority Academic Program Development of Jiangsu Province
文摘The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.
