不同催化体系对乙丙共聚物序列分布的影响

<正> 乙丙橡胶的性能不仅取决于共聚物的组成、分子量及其分布,而且依赖于共聚物的微结构。Natta等认为共聚物中乙烯和丙烯单体链节呈无规分布时可获得性能最好的弹性体。但因催化剂及聚合条件不同,共聚物的单体链节总是存在不同程度的无规、交替及长序列分布。本文采用红外吸收光谱研究了乙丙共聚物的组成及不同催化体系和加入添加剂后对乙丙共聚物序列分布的影响。     

SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE) SIDE CHAIN STRUCTURES**

Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called "selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed "comb- model" was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.     

RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE BY LANTHANOCENE CATALYSIS*

Ring-opening polymerization of ε-caprolactone (CL) catalyzed bylanthanocenes, O(C_2H_4C_5H_3CH_3)_2YCl (Cat-YCl) and Me_2Si[(CH_3)_3SiC_5H_3]_2NdCl(Cat-NdCl) has been carried out for the first time. It has been found that both yttroceneand neodymocene are very efficient to catalyze the polymerization of CL, giving high molec-ular weight poly (ε-caprolactone) (PCL ). The effects of [cat] / [ε- CL] molar ratio, polymeriza-tion temperature and time, as well as solvents were investigated and polymerization tem-perature is found to be the most important factor affecting the polymerization. The bulkpolymerization gives higher molecular weight PCL and higher conversion than that in solu-tion polymerization. NaBPh_4 was found to promote the polymerization of ε-caprolactone,and thus to increase both the polymerization conversion and MW of poly (ε- caprolactone ).     

用差减红外光谱分峰法测定乙丙齐聚物中端羟基的微结构

合成了端羟基乙丙齐聚物。用差减红外光谱对端羟基进行了分析。扣除了溶剂中三氯甲烷的干扰,用RUN.CAPR程序进行分峰,以正戊醇-1、3-甲基丁醇-1和丁醇-2为模型化合物标定伯、仲羟基吸收峰位置,并进行蜂面积积分,用模型化合物回归处理后得到定量公式:A=15.8667×10~3Cp+0.25674,以此求得乙丙齐聚物中伯、仲羟基的官能度。     

PASP调控球形碳酸钙沉积过程研究

本文以聚天冬氨酸(PASP)为有机质模板,采用碳化法研究了水溶液中碳酸钙的沉积过程,利用FT-IR、XRD、SEM及粒度分析等方法对碳酸钙沉积样品晶型和晶貌进行了表征,并结合生物矿化的基本原理分析了晶体形成和成长变化过程.结果表明,有机质PASP能够调控碳酸钙沉积由方解石型转变为球霰石型,晶体形貌由菱形转变为球形,同时晶体平均粒径减小64.3;,且粒径分布收窄.主要原因是PASP模板中相邻两-COO-间距离与Ca2+的12配位体空间构型中的两个氧原子间距离相匹配,碳酸钙颗粒经过介晶形成了表面为小颗粒附着的球形晶体,PASP吸附在颗粒表面能够抑制晶体生长.     

1-辛烯的Ziegler-Natta聚合动力学(Ⅱ)——速率增长期的动力学及其机理

用膨胀计研究了络合Ⅱ型TiCl₃-烷基铝催化1-辛烯聚合的非稳态期动力学,发现速率增长期随[TiCl₃]、[M]₀的增大及温度升高而变短。通过显微镜观察发现增长期中催化剂大颗粒逐步破碎成较小颗粒。对此提出了聚合物促使催化剂颗粒破碎从而增大活性表面的增长期机理模型,用此模型解释了大部分实验现象。     

弱 Hopf 超代数 wsldq(m|n)

该文依据弱Hopf代数的定义给出弱Hopf超代数的定义. 进而利用弱反极取代Hopf代数中反极的方法, 构造一类不是Hopf超代数的弱Hopf超代数wsl^d_q(m|n), 并给出了wsl^d_q(m|n)的PBW基.     

形变预投射代数与量子群的表示

设$(\Gamma, I)$是约束循环箭图, 其顶点对应于Abel群$\Z_d$. 给出了所有 $(\Gamma, I)$的不可分解表示以及其中可扩张成相应形变预投射代数 $\Pi^\lambda(\Gamma, I)$的不可分解表示的条件. 证明了由$(\Gamma, I)$的 可扩张不可分解表示提升得到的$\Pi^\lambda(\Gamma, I)$的表示一定是其 所有单表示, 从而通过形变预投射代数的方式实现了限制量子群 $\ol{U}_q({\rm sl}_2)$的所有单表示.     

COMPATIBILITY STUDIES ON POLYMER/WAX AND POLYMER/RESIN-ASPHALTENE BY VISCOMETRY AND PHOTOMICROGRAPHY

The compatibility of mixtures of polymeric pour point depressants, i.e. poly(ethylene-co-vinylacetate) (EVA), poly (EVA-graft-octadecylacrylate) (EVA-g-POA ), poly (ethylene-co-octadecylacrylate) (EOA) and poly(ethylene oxide-co-propylene oxide) (EO-co-PO) withwax or resin-asphaltene from crude oil have been studied by means of dilute-solution vis-cometry. It was found that each mixture pair is incompatible, but the degrees of incompati-bility are quite different, which are in good agreement with the results from photomicrog-raphy.     

不同催化体系制备的乙烯丙烯共聚物的~（13）C—NMR研究

本工作利用样品１３－ＮＭＲ波谱的全部数据，把它们分成六组，考虑丙烯反插的情况，建立三元共聚合模型计算了各类催化体系得到的乙烯丙烯共聚物的序列分布，动力学参数．结果和实测值吻合得很好．该计算模型既适用于反插丙烯存在的情况也适用于反插丙烯不存在的情况，对于分辨率较差的谱图也可直接从组峰面积进行计算，既避开了分峰的困难，也避免了勉强分峰带来的误差，可得到良好的结果