Kinetics of two-step anionic polymerization

This article deals with the kinetics of two-step anionic polymerization by way of a non-steady state method. Several molecular parameters can be evaluated using the formulae developed. A bimodal molecular weight distribution function for the resulting polymer is derived from the set of kinetic differential equations, which is in agreement with the experimental data reported.     

聚合物载体－稀土金属络合物的研究 ⅩⅢ．聚［苯乙烯－甲基丙烯酸β（甲基亚硫酰基）乙酯］的结构与其稀土金属络合物催化丁二烯聚合的活性

从测得的竞聚率计算了单体链节在聚［苯乙烯－甲基丙烯酸β（甲基亚硫酰基）乙酯］（ＰＳＭ）中的序列分布。苯乙烯（Ｓ）或甲基丙烯酸β（甲基亚硫酰基）乙酯（Ｍ）的长序列的概率随着ＰＳＭ中相应单体含量的增加而增加。对于Ｓ和Ｍ摩尔分数大致相等的ＰＳＭ，单体链节的长序列分布函数值相接近。用与此结构相近的ＰＳＭ合成的稀土金属络合物，其催化活性不佳。在Ｍ短序列分布和Ｓ长序列分布较高的情况下，络合物的催化活性最好。所得聚丁二烯的微观结构与ＰＳＭ中单体单元的分布无关。     

原位插层聚合制备PVC/蒙脱土纳米复合材料

采用氯乙烯单体直接插层到蒙脱土中进行原位插层聚合，制备纳米复合材料，并用小角X射线衍射（XRD）、扫描电子显微镜（SEM）和电子探针技术对复合材料进行了结构表征。实验结果表明：采用原位插层聚合法制得的PVC／蒙脱土（MMT）复合材料为剥离型纳米复合材料。     

聚苯乙烯生产工艺及其产品性能的改善

介绍了苯乙烯单体热引发本体聚合的特点及美国FINA石油化学公司聚苯乙烯生产工艺的特点，探讨了影响HIPS产品质量的多种因素，并对HIPS产品质量的改善提供提出建议和看法。     

Synthesis and properties of peroxy derivatives of epoxy resins based on Bisphenol A: Effects of the presence of boron trifluoride ethereate

Oligomers containing peroxy groups have been synthesized on the basis of epoxides reacting with tert–butylhydroperoxide in the presence of boron trifluoride etherate. Dependence of reaction rates upon the quantity of catalyst, temperature and also nature of hydroperoxide has been investigated: A kinetic equation for the process has been formulated and also a kinetic scheme for the reaction taking into account the presence of boron trifluoride etherate is proposed. Structures of the synthesized peroxy oligomers have been confirmed by IR- and NMR-spectroscopy. The reaction initiating properties of the oligomers so synthesized were studied using as the example the styrene polymerization reaction. Electronic Publication     

PEG20000中试放大的工艺研究

在一定温度和催化剂作用下 ,分别利用本体聚合和溶剂聚合的方法 ,在 1L、10 0L不锈钢高压反应釜中合成了相对分子质量为 2 0 0 0 0的聚乙二醇 ,并讨论了聚合反应机理 ,研究了催化剂用量、反应温度、反应时间对聚合反应的影响。经过红外、核磁共振、凝胶色谱、化学分析等方法对产物进行了表征。     

烯烃聚合单活性中心非茂催化剂的最新研究进展

综述了近几年来烯烃聚合用单活性中心非茂催化剂的研究进展。简要介绍了 2 3种由前、后过渡金属组成的配位化合物催化剂的结构与性能     

Preparation of flexible polyhedral particles via concentrated emulsion templating polymerization

This paper presents recent efforts on the preparation of flexible polyhedral particles via concentrated emulsion templating polymerization in which the hydrophilic monomer (acrylamide) and hydrophobic monomer (butyl acrylate) are polymerized simultaneously in the continuous and dispersed phase, respectively. Such templating polymerization has been enhanced in our systems owing to the introduction of acrylamide monomer and their higher polymerization rate in continuous phase as compared with butyl acrylate in dispersed phase. Diffusion between the different phases was also inhibited. Furthermore, the stability of the concentrated emulsion and the molecular weight of the produced poly(butyl acrylate) were found to be significantly affected by the amount of redox initiator. The morphology of the particles could be controlled by varying the volume fraction of the dispersed phase and the polyhedral particles were achieved at higher volume fraction. Copyright © 2005 Society of Chemical Industry