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。

Before degradation: limpid stereo reticular structure of PLGA; One week after degradation: PLGA was corroded and the reticular structure was decreased; Three weeks after degradation: airspace was gradually disappeared and the reticular structure was further decreased; Five weeks after degradation: airspace and the reticular structure were completely damaged, which was in an indefinite form.

降解前PLGA(丙交酯和乙交酯的摩尔比为90∶10)支架材料呈清晰的三维立体网状空隙结构；降解1周后，材料表面受侵蚀，网状结构减少，孔洞局灶性连接呈片状；3周时材料表面受侵蚀现象加重，空隙逐渐消失，网状结构进一步减少，聚合物融合呈大片状；5周后材料空隙、网状结构完全消失，呈不定型均质状。

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。

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。

Lactide, glycolide or caprolactone, biodegradable polyester and diisocyanate as materials are first bulk melt polymerized to prepare the degradable polymer with thermal deformation transforming temperature of about 37 deg.c. The obtained material is processed at temperature over melting temperature so as to shape into spiral rack, applied with stress at temperature higher than Ttrans to form shape easily operational handling and frozen to eliminate stress into the product.

本发明以丙交酯、乙交酯或己内酯，生物可降解聚酯及二异氰酸酯为原料，通过本体熔融聚合制备得到热致形变温度转化点在37℃左右的可降解高分子材料，将得到的材料在熔融温度以上进行加工、赋形制作成用于不同管腔内的螺旋管状支架；在T＞T trans 条件下施加应力，加工为便于手术操作的形状；冷冻定型消除应力，即得产品。

Degradation test in vitro was carried out in phosphate buffer solution (0.1M, pH7. 4) at 37 ℃. The buffer solution was changed daily. Degradation test in vivo was implanted the sample to subdermal in adult ICH rat in the scapular area lateral to the dorsal midline. At suitable time the samples were recovered. Molecular weight changes in surface layer and bulk of polymer sample were measured by GPC and weight loss was determined gravimetrically. It was found that the degradation behavior can be regulated by changing the composition of copolymers. The critical compositions from surface to bulk degradation behavior for PGCA, PLCA, PLMCA, PLDCA systems were 15-20, 20-30, 30- 40, 40 of mol percent GA or LA unit in copolymers, respectively. The degradation behavior of PGCA, PLCA, PLMCA, PLDCA systems were compared and analysed. Some factors influencing the degradation character, such as copolymer composition, hydrophobicity, crystallinity and enzyme affect etc. played important role.

体外实验中材料降解环境为37℃，0.1M，pH7.4磷酸缓冲溶液，每天换液，定期取样；体内实验中将聚合物试样埋置于ICH小白鼠背部肩胛骨皮下部位，定期处死小鼠，取样，将体内体外样品进行重量损失及试样内外层分子量变化测定，分析各聚合物试样降解行为特性，实验结果证明，改变共聚物组成，可以调节各聚合体系降解行为特性，对PGCA，PLCA，PLMCA，PLDCA共聚体系，交酯摩尔百分含量15-20％，20-30％，30-40％，40％分别为各体系内降解行为特性由表面降解型向本体降解型过渡的临界转折点，交酯含量较低的聚合物不同程度地表现表面降解行为特性，论文对各共聚体系体内外降解行为作了分析对照，例如共聚物组成对材料降解速度与降解行为的影响；生物体内酶对降解行为的影响；材料亲疏水性，聚合物链段结晶行为及碳酸酯结构对材料降解行为的影响等，得出交酯/环碳酸酯共聚体系降解行为一些共性和规律。

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。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。