CAJ | 학술논문

背景:通过对合成工艺和催化剂的优化和选择,合成较高相对分子质量的聚乳酸生物降解材料.方法:实验于2003-02/2004-10在哈尔滨工业大学市政环境工程学院绿色化学与技术研究中心完成.以L-乳酸为原料,通过熔融缩聚的一步法合成可生物降解的聚L-乳酸.乳酸首先在无催化剂存在条件下发生自催化缩聚反应,生成较低相对分子质量的预聚物OLLA;然后将催化剂加入到OLLA中继续反应,最后得到较高相对分子质量的聚乳酸.实验考察了预聚条件、催化剂种类和用量、催化剂溶解程度、聚合温度及反应时间对聚乳酸分子量的影响.采用傅立叶变换红外光谱仪和核磁共振氢谱对聚合物结构进行了分析确认,通过凝胶气相色谱测定了聚合物的相对分子质量分布.结果:L-乳酸在140 ℃下,先在30 kPa下脱水反应2 h;然后减压至5 kPa继续反应4 h,可得到黏均相对分子质量(Mη)为6 500左右的OLLA.以SnCl2-TSA复合体系为催化剂,按SnCl2与OLLA质量比= 0.4%,TSA:SnCl2=1.0(mol/mol)的用量和配比,将催化剂加入OLLA中并充分溶解后,在165 ℃左右,5 kPa下搅拌反应8 h左右,至反应物出现爬杆现象时终止反应,可得到Mη约为65 000的聚L-乳酸.结论:在优化的工艺条件和催化剂下,能够在较短时间(8 h)内获得较高相对分子质量的聚L-乳酸,使该生物降解材料具备了一定的实用价值.
배경:통과대합성공예화최화제적우화화선택,합성교고상대분자질량적취유산생물강해재료.방법:실험우2003-02/2004-10재합이빈공업대학시정배경공정학원록색화학여기술연구중심완성.이L-유산위원료,통과용융축취적일보법합성가생물강해적취L-유산.유산수선재무최화제존재조건하발생자최화축취반응,생성교저상대분자질량적예취물OLLA;연후장최화제가입도OLLA중계속반응,최후득도교고상대분자질량적취유산.실험고찰료예취조건、최화제충류화용량、최화제용해정도、취합온도급반응시간대취유산분자량적영향.채용부립협변환홍외광보의화핵자공진경보대취합물결구진행료분석학인,통과응효기상색보측정료취합물적상대분자질량분포.결과:L-유산재140 ℃하,선재30 kPa하탈수반응2 h;연후감압지5 kPa계속반응4 h,가득도점균상대분자질량(Mη)위6 500좌우적OLLA.이SnCl2-TSA복합체계위최화제,안SnCl2여OLLA질량비= 0.4%,TSA:SnCl2=1.0(mol/mol)적용량화배비,장최화제가입OLLA중병충분용해후,재165 ℃좌우,5 kPa하교반반응8 h좌우,지반응물출현파간현상시종지반응,가득도Mη약위65 000적취L-유산.결론:재우화적공예조건화최화제하,능구재교단시간(8 h)내획득교고상대분자질량적취L-유산,사해생물강해재료구비료일정적실용개치.
AIM: To synthesize biodegradable poly lactic acid (PLA) through the optimization and selection of process and catalyst.METHODS: This experiment was performed at the Research Center for Green Chemistry and Technology in the School of Municipal and Environmental Engineering of Harbin Institute of Technology from February 2003 to October 2004. Biodegradable poly L-lactic acid (PLLA) was synthesis by melt polycondensation using L-lactic acid (LA) as material. Firstly, oligo L-lactic acid (OLLA) was prepared by dehydrating aqueous solution of LA without catalyst. And then, the mixture of OLLA and catalyst was heated at a certain temperature and pressure for a period of time to get the product of PLLA. The structure of PLLA was characterized by Fourier transform infrared (FTIR) spectra and 1H- nuclear magnetic resonance (1H-NMR) spectra. The polydispersity was determined by gel permeation chromatography (GPC).RESULTS: OLLA with the viscosity average molecular weight (Mη) of 6 500 g/mol was prepared by the following steps: the solution of LA without catalyst was dehydrated at 140 ℃, first at reduced pressure of 30 kPa for 2 hours, and then at 5 kPa for 4 hours. SnCl2-p-toluenesulfonic acid (TSA) system was the effective catalyst for the polycondensation of OLLA. After the mixture of OLLA and catalysts polycondensed at 165 ℃ and 5 kPA for about 8 hours, PLLA with the Mη of 65 000 g/mol was obtained by using SnCl2-TSA system as catalyst with the SnCl2 amount of 0.4wt% to OLLA and equal mol ratio of SnCl2 and TSA.CONCLUSION:PLLA with a certain practicability was obtained under the optimal process and catalyst. Oligomerization of LA played an important role on improving the molecular weight of PLLA.