A#H^＊rat为中心单代数的条件

本文用ＭｏｒｉｔａＣｏｎｔｅｘｔ的方法得到域上余ＦｒｏｂｅｎｉｕｓＨｏｐｆ代数Ｈ与Ｈ－余摸代数Ａ的Ｓｍａｓｈ积Ａ＃Ｈ＊ｒａｔ是中心单代数的条件：若Ａ／ＡＣｏＨ是Ｈ－Ｇａｌｏｉｓ扩张，且ＡＣｏＨ是中心单代数，则Ａ＃Ｈ＊ｒａｔ也是中心单代数，特别地，若ＡＣｏＨｋ，则Ａ＃Ｈ＊ｒａｔ是中心单代数，且为ｋ－空间Ａ上线性变换稠密环．作为推论给出Ｈ＃Ｈ＊ｒａｔ是本原中心单代数新的证明．     

~(13)C-NMR STUDY OF ETHYLENE-1-OCTENE COPOLYMERS

A ~(13)C-NMR method is presented for a quantitative determination of the respective monomercomposition and sequence distributions in ethylene-1-octene copolymers prepared with supportedtitanium/magnesium catalyst. On the basis of the sequence distributions, the ethylene-1-octenecopolymerization mechanism was studied. It was found that the observed sequence distributions inethylene-1-octene copolymers are satisfactorily predicted by the two-site model M/M,in whichthe copolymerization proceeds according to first-order Markovian statistics at the two differentsites.     

IMMOBILIZATION OF POTENTIALLY BIOACTIVE MOIETIES ONTO POLYETHER WITH POLY(ETHYLENE GLYCOL)-SULFONATE SPACER

A new reactive graft copolymer, poly(tetramthylene glycol) - graft-w-propyl sodiumsulfonate-poly(ethylene glycol) (PTMG-g-PEG-CH_2CH_2CH_2SO_3~-Na~+), was synthesizedby the cationic polymerization of a-w-bifunctional PEG macromonomer (O?CH_2—PEG——CH_2 CH_2 CH_2 SO_3 Na) and THF. The obtained copolymer exhibits the expected structureas indicated by the result of characterization. Two amino acids (L-arginine, L-tyrosine)were covalently attached to the copolymer after converting the sulfonate group to sulfonylchloride. So the new reactive graft copolymer (PTMG-g-PEG-CH_2CH_2CH_2SO_3~-Na~+) isexpected to be very useful in attachment of potentially bioactive moieties to polymer viaa hydrophilic PEG spacer.     

1-辛烯Ziegler-Natta聚合的活性中心多分散性——分子量分布及动力学的研究

本文通过对TiCl_3-Al(C_2H_5)_3聚合1-辛烯产物的双峰型分子量分布曲线用Schulz函数进行拟合、分峰处理,发现这种双峰型分布中的高分子量峰部分由一种活性中心生成,低分子量峰部分则由至少两种活性中心生成.将不同转化率时聚辛烯的分子量分布分峰拟合数据与聚合速率、活性中心数等测定数据相结合,得到了高分子量和低分子量两部分产物相应的活性中心上各自的动力学参数(增长速率常数、活性中心数、链转移常数等)及各自的聚合速率曲线,从而证实了多种活性中心的存在、它们催化特性的差异及与聚合物分子量分布增宽的关系.     

苯乙烯-马来酸酐自由基共聚反应 (Ⅰ)苯乙烯-马来酸酐电荷转移络合反应

电荷转移络合反应机理是研究苯乙烯－马来酸酐自由基交替共聚反应机理的关键。本文简述了苯乙烯－马来酸酐电荷转移络合反应的研究进展。     

STUDY ON HIGHLY ACTIVE ZIEGLERNATTA CATALYSTS FOR POLYMERIZATION OF OLEFINS

In this paper, highly active Ziegler-Natta catalysts of MgCl_2 supported TiCl_4 for synthesis ofpolyolefins, using di-n-butyl phthalate (DNBP) as internal donor and diphenyl dimethoxyl silane(DPDMS) as external donor, have been prepared. The conditions controlling the treatment ofsupport were studied. The interactions of various components present in the catalysts and theirinfluences on catalytic performance were investigated. It is found that by using DNBP and DPDMSas internal and external donors together the polymer products with higher isotactic index can beobtained. Plausible structure model and mechanism were proposed.     

阳离子聚合合成聚苯乙烯大分子单体

<正> 近十年来,对大分子单体的合成和表征进行了较广泛的研究,其中尤以聚苯乙烯大分子单体研究得更多。Milkovich等用阴离子聚合合成了一系列具有不同端基的大分子单体。本文采用实验要求比阴离子简单的阳离子聚合方法,用对-氯甲基-β-溴乙苯和三     

聚苯乙烯大分子单体与醋酸乙烯酯接枝共聚物的合成及表征

<正> 用大分子单体与小分子单体共聚是七十年代初才出现的合成接枝共聚物的一种新方法。通过共聚合反应而不是接枝反应同时形成主干及支链。这种接枝共聚物由于形成支链的大分子单体是预先合成的,其分子量分布较窄,又可调节控制,所以合成的接枝共聚物支链长短比较均一,副反应较少,链结构比较明确,因此也易于表征。     

STUDY ON THE MECHANISM OF 1-OCTENE ZIEGLER-NATTA POLYMERIZATION BASED ON THE NUMBER OF ACTIVE CENTERS

The number of active centers (C_p)-t and k_p-t profiles of Solvay type TiCl_3 - AlR_3 (R=C_2H_5, i-C_4H_9) or Stauffer AA TiCl_3-Al (C_2H_5)_3 catalyzed 1-octene polymerization were determined by using an acetyl chloride quenching method as well as kinetic data. The results show that in the studied systems k_p decreases when C_p increases, indicating the presence of two or more types of different active centers. The C_(p~(-t)) plots of the Solvay TiCl_3-AlR_3 systems show the presence of both stable active centers and unstable centers which decay in the polymerization process. The phenomena are explained based on a model of active center plurality. The increases of C_p in the induction periods are also discussed.     

聚氧乙烯交联网络-硫氰化钠络合体系离子电导的研究

合成了甲基丙烯酸聚氧乙烯酯大分子单体,其中含有少量双端酯化的单体。大分子单体经热交联,形成交联网络型聚氧乙烯,其与硫氰化钠形成的络合物的室温电导率较同类线型聚合物高二个数量级以上(～10~(-5)Ω~(-1)cm~(-1)/298K)。红外光谱表明:交联网络含较高的非晶成份。不同络合溶剂对形成的络合物聚集态有明显影响;络合盐浓度也对络合物结晶性有影响。