交酯

• Lactide were investigated . the key factors affecting the polymer intrinsic viscosity were found to be monomer recrystallization times , stannous octoate concentration and polymerization time . the thermal stabilizing agent did not significantly affect the polymer molecular weight . the polymer with a viscosity average molecular weight beyond 200000 was fairly reproducible by optimizing the polymerization conditions . it was found that poly
  单体重结晶次数辛酸亚锡浓度聚合时间等条件均是影响聚合物特性粘数的重要因素。热稳定剂对聚丙交酯的分子量几乎没有影响。优化聚合条件可以获得粘均分子量大于200000的聚丙交酯材料，聚合结果具有良好的重复性。
• Firstly , after a great deal of investigation and research , the author chose polypropylene ( pp ) and poly ( glycolide - lactide ) ( pgla ) as the tubular fabric material and the acetic acid solution of chitosan as the coating material . polypropylene display superior biomechanical properties while the pgla fiber is characteristic of controllable biodegradability , and chitin integrate the excellent biological properties of both collagen and cellulose
  本文首先选定了人工气管支架织物的编织原料为具有生物学惰性及良好力学性能的医用丙纶和具有优良生物性能的聚乙丙交酯；由于甲壳素兼具高等动物组织中的胶原和植物纤维中纤维素两者的优异生物特性，所以在本课题中采用的人工气管涂层材料为壳聚糖乙酸溶液。
• Pgla , one biodegradable material , is used to braid the conduits , which integrates the merits of its two aggregate ingredients . it is easy to adjust degrading rate to match the regeneration period of the nerve by changing the proportion of the two ingredients . the conduits are fabricated enlacing 2 . 2 millimeter stainless steel on the braiding machine with 16 spindles using 2700 tex yarns . four conduits with different structures are braided : common braided structure , braided structure using braided ply yarn , braided structure with inserted reinforcing yarn and adding bridge - yarn structure , the last two conduits are new attempts to look for good shape - keeping structure , being able to lead the nerve to regenerate effectively
  本课题选用可生物降解材料聚乙丙交酯( pgla )为原料，它兼具两种聚合成分的优点，可以通过调节两者聚合的配比来调节它的降解周期，使与神经再生的周期相吻合。导管的制作是在16锭编织机上采用2700tex纱线进行带芯编织，芯子为直径2 . 2mm的不锈钢丝。共制作四种结构神经导管，分别为普通结构神经导管、编织线结构神经导管、加筋结构神经导管和加芯结构神经导管。
• The product ratio was increased to 45 % from 30 % . furthermore , lactide was recycled from the ethyl acetate recrystallization solution , and structure was investigated with ir and uv spectrum . the result indicated that the process is suitable and feasible , and the product ratio is beyond 40 %
  本文在总结了目前众多聚乳酸单体? ?丙交酯的合成技术的基础上，选用减压蒸馏工艺并加以改进，设计出最佳的实验装置，使丙交酯的产率从30提高到45 ，并对重结晶后的母液进行有效的回收，回收率也能达到40 ，对回收后的丙交酯进行了测试分析，证明了回收过程的可行性。
• ( 5 ) the article also investigate the recrystallization condition of crude lactide and point out that it also an important factor have influence on the purification production ratio . ( 6 ) give the kinetics equation of depolymerization reaction . by determination the degree of polymerization ( dp ) of the reaction system , we can get the kinetics data of the reaction
  本文建议使用乙酸乙酯和异丙醇混合溶剂( 6 ： 4 )对丙交酯粗产物进行重结晶； ( 6 )提出解聚反应的动力学方程，认为它是一个可近似处理为一级反应的连续反应，并可通过测定体系的平均聚合度的方法来得到包括活化能在内的反应动力学数据。
• The cost of lactide is one of the most important factors that hamper the pla from widely use for a long time . in this paper a series of apparatus which can boost the product ratio to the utmost was focused on . meanwhile the factors affecting the molecular weight of pla in the polymerization were also discussed
  长期以来丙交酯的成本一直是制约聚乳酸推广应用的最重要的因素之一，本文致力于设计出一套能最大限度降低丙交酯成本的工艺过程，并对丙交酯聚合过程中影响聚乳酸分子量的因素进行了初步探讨。
• Afterwards , the remnant lactic acid in lactide was measured by non - aqueous titration with sodium methoxide and the remnant water was surveyed by karl - fisher method . the melting point was investigated by thiele tube and the characteristics of lactide were analyzed by ir , uv spectrum , tg and dsc respectively
  然后，用甲醇钠非水滴定法测定丙交酯中残存乳酸，卡尔-费休法测定丙交酯中残存水的含量，用提勒管测定精制丙交酯熔点，用红外吸收光谱、紫外光谱、差热分析对合成的丙交酯以及回收的丙交酯进行表征。