丙交酯

The affections on the yield of DLLA caused by catalyst, temperature and time etc. were studied. By using ethylene glycol as diluent, the distillate temperature of DLLA was lowed and the carbonization phenomenon could be avoided, which caused the yield of DLLA increasing from 36.8% to 51.3%. The molecular weight of PDLLA prepared by this method could reach 184,000. DLLA and PDLLA was characterized and analyzed by DSC, XRD and IR.The key of direct method to synthesize PDLLA is the exclusion of H2O from reaction system.

丙交酯开环聚合制备PDLLA的关键在于中间体D，L-丙交酯的制备，研究了催化剂、反应温度、反应时间等因素对DLLA产率的影响，通过在反应体系中加入稀释剂乙二醇，DLLA的馏出温度明显降低，避免了DLLA在蒸馏过程中产生碳化现象，并使DLLA的平均产率由36.8％提高至51.3％，制备的PDLLA分子量最大值达18.4万。

The reactive time and reactive temperature are two important parameters for yield of lactide.

反应时间和反应温度是制备丙交酯的两个重要的工艺参数，直接影响丙交酯的产率。

This apparatus was designed based on summarizing the most synthetic processes of lactide presently.

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。

Firstly, through analysis for the synthetic mechanism of lactide and according to improve the condition of synthetic process the factors related were studied in detail.

首先，从改善合成丙交酯反应的条件入手，通过对丙交酯合成反应的机理分析，对反应过程中催化剂用量、种类、脱水温度、时间、压力、解聚温度、时间、压力等做了详细的研究，得出最佳的合成条件和工艺过程。

An indirect spectrophotometric method was used to determine the content of lactide. The factors on the determination, such as the type of solvent, acid and alkali dosage, the time of aminolysis reaction and so on, were discussed.

采用间接光度法测定粗丙交酯中丙交酯的含量，讨论了溶剂类型、胺解反应时间、酸碱用量等因素对测定结果的影响。

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。

This paper reviewed the recent development of synthesis of propyl lactide,discussed the effects of different synthesis techniques and various catalyst system s for the preparation of propyi lactide on the yield and discussed the prospect of propyl lactide synthesis.

介绍了丙交酯合成研究的最新进展，比较了不同催化体系和不同合成工艺对丙交酯收率的影响，并对丙交酯合成的发展前景进行了展望。

Objective To study the pH and temperature sensitive properties of sulfamerazine oligomers-polyε-caprolactone-co- DL -lactide-b-ethyleneglycol- b -ε-caprolactone-co-DL-lactide-sulfamerazine oligomers（OSM1-PCLA-PEG-PCLA-OSM1）block copolymer and evaluate sustained release effect of 5-fluorouracil release from the loaded hydrogel in vitro.

摘要目的为嵌段共聚物磺胺甲嘧啶低聚物-聚-ε-己内酯-丙交酯-聚乙二醇-聚-ε-己内酯-丙交酯-磺胺甲嘧啶低聚物（sulfamerazine oligomers-poly(ε-caprolactone-co- DL -lactide-b-ethyleneglycol- b-ε-caprolactone-co-DL-lactide)-sulfamerazine oligomers，OSM1-PCLA-PEG-PCLA-OSM1作为缓控释给药系统的载体提供依据。

A novel biodegradable copolymer of poly and poly (γ-benzyl-L-glutamate) was successfully synthesized. Under appropriate conditions, the PBLG initiates the ring-opening polymerization of L-lactide to produce block copolymer, by using low toxicity stannous octoate as catalyst. The optimal reaction conditions were determined as follows; the catalytic agent: PBLG=1:1, the temperature is 120℃, the reaction time is 6h.

以L-丙交酯为原料，在催化剂辛酸锡酯Sn2的作用下，利用聚的活性端氨基引发LLA进行开环聚合，合成了聚L-丙交酯与聚的共聚物，对反应条件的各项因素进行了讨论，确定了最佳反应条件是：m：m=1：1；反应温度120℃；反应时间6h。

Linear and star-shaped hydroxy-terminated polys were synthesized by reacting L-lactide with co-initiators such as poly,hydroxyethyl methycrylate,trimethylolpropane,mannitol and sorbierite in the presence of stannous octoate as catalyst.

以辛酸亚锡为催化剂，分别以聚乙二醇、甲基丙烯酸羟乙酯、三羟甲基丙烷、季戊四醇、甘露醇和山梨醇等和L-丙交酯反应，得到末端为羟基的线形和星形聚L-丙交酯。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。