【摘要】 以廉价的外消旋乳酸(D,L-LA)和缬氨酸(Val)为原料,以氧化亚锡为催化剂,采用熔融聚合法合成了新型生物材料聚(乳酸-缬氨酸)共聚物。用特性粘数[η]、FTIR、1H NMR、DSC、GPC、XRD等测试技术对其结构进行了表征,考察了不同投料比对共聚物的影响。结果表明,当投料比n(LA)∶n(Val)=95∶5时,Mw=7 300,Mn=5 400,共聚物相对分子质量最大,结晶度(13.5%)要比均聚物聚外消旋乳酸(PDLLA)的低。随着投料比中Val含量的增加,共聚物相对分子质量逐渐降低,由结晶态逐渐转变为无定形态。但所得共聚物的Mw均大于1 800,Tg、Tm均与PDLLA的相接近,能够满足生物降解材料在药物缓释领域中的应用。更多还原

【Abstract】 With cheap D,L-Lactic acid(D,L-LA) and valine(Val) as the stanting materials,and SnO as the catalyst,a novel biomaterial,poly(lactic acid-co-valine)co-Val),was directly synthesized via melt copolycondensation.The copolymer was characterized with viscosity measurements,FTIR,1H NMR,DSC,XRD and GPC.The effects of feed molar ratio were discussed.When the feed molar ratio n(LA)∶n(Val) was 95∶5,the weight-average molecular mass(Mw) was 7 300,the number-average molecular mass(Mn) was 5 400,which were all the highest.Its crystallinity(13.5%) was lower than that of homopolymer poly(D,L-lactic acid)(PDLLA).With the increase of the feed molar ratio of Val,Mw of the copolymer P(LA-co-Val) gradually became smaller,and the crystallinity gradually disappeared.But the lowest Mw of 1 800 and the glass-transition temperature(Tg) and the melting temperature(Tm) of the copolymer were similar to that of PDLLA,which could meet the requests for the application in drug delivery of this biodegradable material.更多还原