外消旋乳酸直接熔融聚合-二异氰酸酯TDI熔融扩链的研究  

Studies on the Synthesis of Poly(D,L-lactic Acid)s Biodegradable Material through Direct Melt Polycondensation-Diisocyanate Chain Extension by TDI in Melt State

作　　者：汪朝阳[1] 赵耀明[2] 王浚[2] 李雄武[1] 

机构地区：[1]华南师范大学化学系,广东广州510006 [2]华南理工大学材料学院,广东广州510640

出　　处：《材料科学与工程学报》2007年第1期35-39,共5页Journal of Materials Science and Engineering

基　　金：高等学校博士学科点专项科研基金资助项目(20050561020);广东省自然科学基金资助项目(020885);广东省自然科学基金博士科研启动基金资助项目(5300082)

摘　　要：用2,4-甲苯二异氰酸酯(TDI)对以外消旋乳酸(D,L-LA)直接熔融聚合合成的低分子量聚外消旋乳酸(PDLLA)进行扩链,用粘均分子量、红外光谱(IR)、核磁共振氢谱(1H NMR)、DSC、X-射线衍射等对扩链产物进行了表征。在SnCl2催化下,NCO/OH=1,160℃下反应60min,可得到Mη为扩链前3.42倍的可溶性聚乳酸类生物降解材料。IR1、H NMR表明熔融聚合-TDI熔融扩链产物引入了NH和苯环,DSC、XRD等表征发现扩链使Tg、Tm和结晶度等相应提高。但是,温度过高、时间过长、NCO/OH过大时,易生成可溶性差的交联副产物,较多副产物的混杂会导致Tg和结晶性的降低。Starting from cheaper D,L-lactic acid （D,L-LA）, lower molecular weight pely（D,L-lactic acid） （PDLLA） was directly synthesized via melt pelycondeusation. And then, using PDLIA as prepelymer, and 2,4-toluylene diisocyanate （TDI） as chain extender, pely （D, L-lactic acid）s biodegradable material was synthesized through diisocyanate chain extension in melt state. Catalyzed by SnCl2, under the chain extension conditions, including NCO/OH molar ratio 1.0, temperature 160℃ and time 60min, viscosity-average molecular weight （Mη） of chain extension product dissolvable in chloroform Could be 3.42 times higher than before. The structure of the product extended by TDI was characterized with FTIR and ^1H NMR. And the chain extension product （TDI-PDLLA） had higher glass transition temperature （Tg）, melting temperature （Tm）, and crystallinity than prepelymer PDLLA. However, cross-linking by-preducts with worse solubility in chloroform was apt to be produced once the reaction temperature was higher, or the reaction time was longer, or the molar ratio of NCO/OH was bigger. The existence of more cross-linking by-products made the Tg and crystallinity of TDI-PDLLA decrease.

关 键 词：外消旋乳酸(D L-LA) 2 4-甲苯二异氰酸酯(TDI) 扩链 聚乳酸 生物降解材料 

分 类 号：TQ322[化学工程—合成树脂塑料工业]