THE POLYMERIZATION OF METHYL METHACRYLATE WITH A NEW TIN-BRIDGED YTTROCENE/Al(i-Bu)_3

ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｅｐｏｌｙｍｅｒｉｚａｔｉｏｎｏｆｍｅｔｈｙｌｍｅｔｈａｃｒｙｌａｔｅ(ＭＭＡ)ｗｉｔｈｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｗａｓｒｅａｌｉｚｅｄｆｏｒｔｈｅｆｉｒｓｔｔｉｍｅｉｎ1991,ａｓｅｒｉｅｓｏｆｎｅｗｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｙｓｔｅｍｓｓｕｃｈａｓＮｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3,Ｎｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3/ＣＣｌ4,Ｎｄ(Ｏｃｔ)3/Ａｌ(ｉＢｕ)3,Ｌｎ(ａｃａｃ)3/ＢｕＭｇＣｌ,Ｙ(ａｃａｃ)3/Ａｌ(ｉＢｕ)3/ＢｕＬｉ,Ｎｄ(ｎａｐｈ)3/ＢｕＬｉ,ａｎｄＮｄ(Ｏ…     

Polymerization of methyl methacrylate with iron-ytterbium dinuclear metallocene catalyst

A novel iron-ytterbium dinuclear catalyst, FcB(MeCp) Yb (MeCp) Cl (Fc: ferrocenyl, B: diethylene ether), was synthesized for the polymerization of methyl methacrylate (MMA). Synergistic effects between the ferrocenyl group and the lanthanocene part were investigated regarding their catalytic behaviors. UV, IR, GPC and NMR were used to characterize the structures of the catalyst and polymer. Kinetic study showed that polymerization is first order in monomer concentration and fractional order (0.78) in the catalyst. The bimetallic complex is a good catalyst for the polymerization of MMA, giving high molecular weight PMMA with 78% syndiotactivity. Project (29774021) supported by NSFC and Laboratory of Rare-Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences     

Modeling for the diffusion limitation of free radical polymerization

A new model was developed to describe the diffusion limitation on free radical polyme-rization. In this model the termination rate coefficient (k _t) and propagation rate coefficient (k _p) were expressed as a function of bulk viscosity (η). This model was used to simulate the batch thermal polymerization of styrene (St) and the continuous thermal bulk copolymerization of St (monomer 1) and maleic anhydride (MAH, monomer 2) in a CSTR with on-line monitor of the rheological behavior. The simulated results on polymerization conversion, copolymer composition, molecular weight and its distributions were compared with the experimental data, and the results calculated by two previous gel-effect models i.e. Martin-Hamielec and Tulig-Tirrell models. It was found that the present model produces better prediction than that of the Tulig-Tirrell model and has the same accuracy as that of the Martin-Hamielec model, but is much simpler. Project (29734130) supported by Natural Science Foundation of China.     

天津体育学院师资队伍“断层”问题及其相应对策

通过对天津体育学院师资队伍现状的年龄结构，职称结构，学历层次结构以及部分科研成果分布统计分析，提出天津体育学院师资队伍的“断层”现象，并针对这一现象提出了解决问题的相应对策，供学校各级领导决策参考。     

高分子化学悬浮聚合实验教学系统的开发

利用当前通用的多媒体技术、以多媒体制作工具Authorware为主,其它一些主流的媒体创作工具为辅,制作了高分子化学悬浮聚合实验教学系统。它由7个模块组成,即实验目的模块、实验原理模块、实验设备模块、实验步骤模块、实验问题模块、实验设计模块、退出系统模块。它不仅可以作为高分子化学实验教学使用,又便于学生有效地进行实验的预习和复习。该教学系统使用方便、操作简单、针对性强、是一种较实用的计算机辅助教学工具。     

RESEARCH ON DISTURBANCE PROPERTIES OF SUSPENSIONS NEAR THE INJECTION AREA OF MOVING JET

ＩＮＴＲＯＤＵＣＴＩＯＮＭｏｖｉｎｇｊｅｔｃｏｎｔａｉｎｉｎｇｓｕｓｐｅｎｓｉｏｎｓｉｎｃｌｕｄｉｎｇｃｏａｌｐｏｗｄｅｒ,ｄｒｏｐｌｅｔｓａｎｄｓｏｏｎｗｉｄｅｌｙｅｘｉｓｔｓｉｎｔｅｃｈｎｉｃａｌａｐｐｌｉｃａｔｉｏｎｓｓｕｃｈａｓａｉｒｃｒａｆｔｕｓｉｎｇｆｕｅｌｆｏｒｐｏｗｅｒ.ＬｉｎＪｉａｎｚｈｏｎｇｅｔａｌ.( 2 0 0 0 )ｗｈｏｓｅｓｔｕｄｙｓｈｏｗｅｄｔｈａｔｔｈｅｅｒｏｓｉｏｎｏｆｗａｌｌｓｏｆａｄｅｖｉｃｅｖａｒｉｅｓｗｉｔｈｔｈｅｃｈａｎｇｅｏｆｔｈｅｃｏｈｅｒｅｎｔｓｔｒｕｃｔｕ…     

悬浮液进样一火焰原子吸收光谱法测定中草药中的锰

将悬浮液进样－火焰原子吸收光谱法应用于中草药中锰的测定，建立了中草药中锰的快速分析新方法，将样品粉碎，磨细悬浮于琼脂胶体中，直接喷入空气－乙炔，火焰，以空白溶液为参比，用氘灯扣除背景吸收，用标准曲线法测定了泽泻中的锰，测定结果与消化法一致，两种方法的相对误差小于3．6％，RSD小于1．8％,t检验表明两种方法之间无显著性差异，方法简便，快速，准确。     

用甲基叔丁基醚为烃化剂合成对叔丁基邻苯二酚的研究

研究了以甲基叔丁基醚为烃化剂合成对叔丁基邻苯二酚。对催化剂的活性,各种副反应及其相应的副产物,投料方式和反应时间等进行了优化考察。当邻苯二酚:甲基叔丁基醚:硫酸=1:1.0:0.1(mol),反应温度110℃,反应时间1.5小时,对叔丁基邻苯二酚的收率达75.7%。     

有机硅改性丙烯酸树脂的制备

有机硅改性丙烯酸树脂(硅丙树脂)的制备方法主要分为物理共混法和化学改性法．综述了近年来关于硅丙树脂制备方面的研究进展，并详细介绍了乙烯基大分子硅单体的制备过程以及硅丙树脂制备过程中乳化体系、单体种类和加料方式等因素对产品性能的影响．     

基于现场实测的某大跨度悬索桥桥址区风场特性

为了对大桥抗风评估提供可靠依据,结合东海某大跨度悬索桥的健康监测系统,同步实测了桥面及桥塔处的风速,采用统计及频谱分析方法对桥面平均风速和风向、风速随高度变化、风速的脉动特性、相关性以及桥面风场的绕流特性等进行了分析.结果表明:加劲梁纵向不同位置处平均风速大小接近,但平均风向差别较大;无量纲幂指数随风速增大呈明显减小的...