Study of catalytic activity of antimony compounds in the polycondensation of bis - hydroxyethyl terephthalate 对苯二甲酸乙二酯缩聚所用锑系催化剂催化活性研究
It is mainly synthesized by two chemical ways : ring - opening polymerization and direct polycondensation 合成聚苹果酸的化学方法主要有开环聚合法与直接聚合法。
Detailedly introduces definition classification and character of interfacial polycondensation and influential factors of polycondensate molecular weight 并着重介绍了界面缩聚的定义、分类、特点以及影响缩聚物分子量的因素。
The amount of catalyst can be reduced by selecting nice solvability catalyst , cutting down the remnant carboxyl amount of esterification and elevating polycondensation temperature 选择溶解性能好的催化剂，降低酯化残存羧基量，提高缩聚温度，可减少催化剂用量。
The preparation methods , reaction mechanism and properties of poly ( malic acid ) synthesized by direct polycondensation are reviewed , and the prospects in this field are also introduced 作者综述了直接聚合法合成聚苹果酸的方法、反应机理及性质，并展望了直接聚合法合成聚苹果酸的前景。
The plant is to produce polyester bottle chips and it is schedule to come onstream in q1 2005 . zimmer will adopt its continuous polycondensation process technology and use pta and eg as feedstock Wap网址： http : xiangsheng . tsou . cn用户仅需通过手机访问集团公司wap网站，就可以查询到相关公司信息产品介绍等。
The present article reviews recent advances in synthesis of biodegradable polyesters , which include aliphatic polyester and polyester containing aromatic constituents , by polycondensation from the standpoint of molecular design 摘要本文从分子设计的角度，综述了缩聚法合成生物可降解聚酯的研究进展，涉及脂肪族聚酯和含有芳香组分聚酯的合成。
The structure of activity of humic was affected by utilization and soil forming mother rock . as the human behavior frequently disturbed the soil , humic molecules weight became less ; polycondensation degree and aromatility of soil humic deceased , and its activity became intense 利用方式和母岩都影响着土壤腐殖质胡敏酸的结构和活性，人为影响愈频繁，土壤腐殖质胡敏酸分子量小、缩合度和芳构化度低、活性强。
These microlites and richer amorphous region will benefit the polycondensation reaction of pet , the diffusion of volatile by - products , and the approach of the end - groups of pet molecular chains by forming more routeways , which may result in the higher rate of ssp 作者认为这些更多数量的微晶体有利于固相缩聚过程中副产物小分子的扩散去除及pet大分子链端基的扩散接近，从而在宏观上表现为pet mmt的固相缩聚速率大大提高。
It is found that changing of catalyst and solvent will influence the relatively reaction velocity of hydrolysis and polycondensation and therefore change the pore structure of resulted silica gel glass matrix . as the result , the ideal prescription for silica gel glass matrix is proposed 确证通过调整催化剂和溶剂的种类及控制干燥化学试剂的添加，可以改变水解和缩聚反应的相对速率，有效实现对硅氧凝胶玻璃基质孔结构的裁剪与设浙江大学博士学位论文计。
