PEO对PLLA/POM共混体系中PLLA结晶行为影响

摘要聚乳酸作为一种可降解的环境友好型的新型生物工程材料，因其同时具有良好的生物相容性、优异的机械性能和降解性能，被大量应用于医用领域、纺织领域、和其它重要领域。然而PLLA制品热稳定性差，尺寸稳定性差等缺点大大限制了PLLA的工业应用。本文通过溶液共混的方式混合了PLLA/PEO二元体系，同时选取5%POM作为固定比例，改变PEO和PLLA的配比得到了PLLA/POM/PEO三元共混物，通过相差偏光显微镜(PLM)、示差扫描热分析(DSC)、广角X射线衍射(WAXD)分析了这两个共混物体系的结晶行为。并在模拟工业应用的条件下对快速淬火后的共混物样品进行了拉伸性能的测试。实验结果表明：在PLLA/PEO二元体系中，PEO的加入对于PLLA的结晶有很大的促进作用，PEO对PLLA结晶的促进作用是通过加快PLLA分子链运动来实现的。在PEO含量占共混物50%以下时，PEO对PLLA结晶的促进作用随着PEO含量的增多愈发明显，然而PEO含量超过50%时，共混物中基体反转，PEO反而稀释了PLLA，抑制了PLLA的结晶。在非等温情况下，POM可通过加速PLLA成核加快PLLA结晶，PEO可通过加快PLLA分子链的运动促进PLLA结晶，在PLLA/POM/PEO三元体系中，POM与PEO可共同作用与PLLA，同时加快PLLA晶体成核和生长两个阶段，促进PLLA结晶。在近似工业成型的快速淬火条件下，PLLA/PEO二元体系中直至PEO含量为50%时PLLA才有微弱的结晶，而在PLLA/POM/PEO三元体系中，实验研究的各组分均有明显的PLLA结晶。这对于改善PLLA热成型时尺寸稳定性差的这一缺点具有重要的工业应用价值。90143

毕业论文关键词：聚乳酸；共混物结晶

ABSTRACT Poly(lactide), as a new kind of a biodegradable material, has been widely applied in medical field, textile field, and other vital areas, for its good biocompatibility, excellent mechanical property and biodegradability。 Whereas its poor thermal stability and dimensional stability has limited its application in industrial field greatly。 The crystallization of PLLA/PEO and PLLA/POM/PEO blends (In PLLA/POM/PEO blends, the content of POM is a fixed value: 5%), which made by solution blending method, has been investigated by using phase contrast polarized optical microscope, differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD)。 Further more, the mechanical properties of quenching blends has been tested in nearly industrial condition。 The results suggest : In PLLA/PEO blends, PEO contributes to accelerate the crystallization of PLLA greatly by activing PLLA chains。 This acceleration effect would be increased as adding the content of PEO until adding up to 50%。 If the content of PEO is beyond 50%, on the contrary, the crystallization of PLLA will be suppressed for the dilution effect of PEO。 When it in non-isothermal conditions, POM accelerates the crystallization of PLLA by speeding up its nucleation, while PEO accelerates the crystallization of PLLA by activing PLLA chains。 Thus in PLLA/POM/PEO blends, PEO and POM jointly accelerate the crystallization of PLLA in both speeding up its nucleation and activing PLLA chains way。 In nearly industrial conditions, quenched PLLA/PEO blends would not crystalize until the content of PEO is adding up to 50%。 While in PLLA/POM/PEO blends, each of the components studied shows fine crystallization, which means a lot for PLLA application in industrial field。源Q于W优E尔A论S文R网wwW.yOueRw.com 原文+QQ75201,8766

Key words : polylactide, crystalline in blend

摘要 1

一、绪论 4

1。1 聚合物共混物 4

1。2 聚合物结晶概况 4

1。3聚乳酸(PLLA)在二元共混物中的结晶行为 PEO对PLLA/POM共混体系中PLLA结晶行为影响:http://www.youerw.com/huaxue/lunwen_195943.html