1,3-PBO扩链改性端羧基聚乳酸的性能表征  

STUDY ON CHAIN EXTENTING AND MODIFICATION OF P(LA/SA) WITH 1,3-PBO

作　　者：樊国栋[1] 李甜甜[1] 白晓丹[1] 张春梅[1] 

机构地区：[1]陕西科技大学化学与化工学院教育部轻化工助剂化学与技术重点实验室,西安710021

出　　处：《高分子学报》2012年第1期14-18,共5页Acta Polymerica Sinica

基　　金：陕西省科技攻关项目(项目号2008K07-32);陕西省教育厅重点实验室重点科研计划项目(项目号09JS061);陕西科技大学研究生创新基金资助

摘　　要：以乳酸为原料、辛酸亚锡为催化剂,采用梯度升温法,在170℃、0.098 MPa条件下直接熔融缩聚合成端羧基共聚物P(LA/SA).将其用2,2-(1,3-亚苯基)-二噁唑啉(1,3-PBO)扩链,按n(—COOH)/n(—oxazoline)=1∶1.4比例加入1,3-PBO,在150℃,0.098 MPa条件下反应15 min制得聚酰胺酯(PEA).采用GPC、FTIR、1H-NMR、DSC、XRD、TGA、SEM等手段对聚合物的结构进行了表征和性能测试.结果表明,与P(LA/SA)相比,扩链产物相对分子质量大幅度提高,重均分子量达36×104;产物Tg比PLA升高,材料的刚性增强;产物热稳定性能提高,为一步分解;产物结晶度较P(LA/SA)降低,其柔韧性较P(LA/SA)增强,但相对于PLA有所降低.The effects of the amount of chain extender,2,2＇-（1,3-phenylene） bis（2-oxazoline） （1,3-PBO） , on the synthesis of lactic acid based poly （ester-amide） （PEA） were studied. The carboxyl-terminated lactic aeid-succinic anhydride copolymer （P（LA/SA） ） was synthesized via directly melt polycondensation of L, D- lactic acid with succinie anhydride and Sn（ 1] ） octoate as the catalyst at 168~C and 0. 098 MPa by the method of a gradient increased temperature. Then, the PEA was synthesized with P （LA/SA） as prepolymer and 1,3-PBO as extender. High molecular weight polymer was produced within a narrow range of eopolymerization parameters. The highest molecular weights were achieved with the molar ratio of oxazoline/carboxyl end groups being 1.0/1.4 at 150~C and 0. 098 MPa for 15 rain. The structure were characterized by spectroscopy （ FTIR and I H-NMR） and the properties were investigated by gel permeation chromatography （GPC）, differertial scanning calorimetry （ DSC ） , X-ray Diffraction （XRD） , thermogravimetric analysis （TGA） and scanning electron microscope （SEM）. Results indicated that the highest molecular weight was over 36 x 104 measured by GPC and the chain stiffness presented a tendency upward detected in mechanical properties as a result of the introduction of benzene rings and amide groups into PLA/SA. A distinct improvement in the thermal stability of the resulting polymer with the chain extender was observed compared with the unmodified PLA by TG,just as an one-step thermal decomposition. The crystallinity of the resulting polymer was higher than that of P（LA/SA）, but lower than that of PLA which indicated that the flexibility of the resulting polymer was superior to P（LA/SA）

关 键 词：聚乳酸 羧基封端 双噁唑啉 扩链 直接熔融缩聚 

分 类 号：O631.3[理学—高分子化学]