淀粉干法酯化改性对淀粉/聚乳酸复合材料紫外老化性能的影响  

Effect of Starch Esterification Performed by Dry Method on UV Aging Properties of Starch/Polylactic Acid Composite

作　　者：左迎峰[1] 顾继友[1] 杨龙[1] 谭海彦[1] 张彦华[1] 

机构地区：[1]东北林业大学生物质材料科学与技术教育部重点实验室,黑龙江哈尔滨150040

出　　处：《林产化学与工业》2014年第6期21-28,共8页Chemistry and Industry of Forest Products

基　　金：中央高校基本科研业务费专项(DL13CB13);国家青年自然科学基金(31200442)

摘　　要：以玉米淀粉为原料,马来酸酐(MAH)为酯化剂,通过干法合成马来酸酐酯化淀粉(ES)。FT-IR测试结果表明,玉米淀粉和MAH通过干法成功发生酯化反应。再将马来酸酐酯化淀粉和聚乳酸(PLA)通过熔融挤出法制备马来酸酐酯化淀粉/聚乳酸复合材料(ES/PLA)。采用紫外老化箱对复合材料进行加速老化处理,研究了干法酯化改性对复合材料老化性能的影响。FT-IR和SEM研究结果表明随着老化时间延长,复合材料中C—O、C—H和CO的吸收峰强度逐渐降低,破坏程度逐渐增大;老化时间相同时,ES/PLA中基团吸收峰强度大于原淀粉/PLA(NS/PLA),破坏程度小于NS/PLA;XRD和DSC结果表明,老化处理后2θ=21°处的结晶峰消失,且16.5°处出现PLA的结晶峰,表明淀粉的水解速率大于PLA;复合材料中PLA的结晶度随老化时间延长先增大,再减小,表明PLA中非结晶区先发生水解。受结晶度的影响,复合材料的热分解温度随着老化时间延长先增大,后减小,且ES/PLA的热稳定性优于NS/PLA。老化时间相同时,ES/PLA的机械性能优于NS/PLA,随着老化时间延长,NS/PLA和ES/PLA的机械强度逐渐降低。Maleic anhydride esterified starch was synthesized by using dry method with corn starch as raw material and maleic anhydride （ MAH） as esterifying agent. FT-IR test results confirmed the successful esterification reaction between the maleic anhydride and corn starch. The maleic anhydride esterified starch was then blended with polylactic acid （ PLA） , and the mixture was melted and extruded to produce the esterified starch/polylactic acid （ ES/PLA） composite. The composite was accelerated aging with UV aging box in order to study the effect of this process on aging properties of composites. FT-IR and SEM results showed that prolonging the aging time led to gradually decrease in the absorption peak strength of C—O, C—H and C—O and gradually increase in the extent of damage to the composite. In the same aging time, the group absorption peak strength of ES/PLA was higher than that of native starch/PLA （NS/PLA）, and the extent of damage was less. XRD and DSC results showed that the crystallization peak of 2θ =21° disappeared and the crystallization peak of PLA at 16. 5° appeared. This indicated that the hydrolysis of starch was faster than that of PLA. With the increase of the aging time, the crystallization of PLA in composites increased first, then decreased. It suggested that amorphous of PLA was first hydrolyzed. Influenced by the crystallinity, thermal decomposition temperature of composites increased first, and then decreased. The thermal stability of ES/PLA was better than that of NS/PLA. Besides, when the aging time was same, ES/PLA performed better mechanical＆amp;nbsp;properties compared with NS/PLA. And with the aging time prolonged, the mechanical strength of NS/PLA and ES/PLA gradually decreased.

关 键 词：干法酯化淀粉 聚乳酸 紫外老化 性能表征 

分 类 号：TQ35[化学工程] TQ028.8