稀土络合催化苯乙烯-马来酸酐配位共聚

本文首次应用稀土配位催化剂NdL_3-A1(i-Bu)_3,在苯溶剂中,50℃下使苯乙烯-马来酸酐共聚,制得富于交替,数均分子量高达6—8.5×10~5的白色粉末共聚物。系统地研究了共聚合反应的特征及动力学行为,共聚合反应具有低的表现活化能(10.5kJ/mol),并且不被对苯二酚所阻聚。不同配体稀土(钕)催化剂活性次序为:Nd(naph)_3>Nd(P_(507))_3～NdCl_3·6H_2O>Nd(P_(204))_3>Nd(acac)_3·3H_2O,并且,初步揭示了共聚合反应的机理——两种单体形成电荷转移络合物参与增长的配位共聚。     

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。     

稀土催化异戊二烯—马来酸酐交替共聚

首次用 Nd( naph) 3 -Al Et3 催化体系合成异戊二烯 -马来酸酐交替共聚物 .实验结果表明 ,共聚反应适宜条件为 :[M]总 =2 .6mol/L( [Ip]/[MAn]=1 ) ,n( Al) /n( Nd) =1 0 ,[Nd]=5× 1 0 -3 mol/L,甲苯 /二氧六环混合溶剂 (体积比为 2 /5) ,于 5℃聚合 2 h.共聚物收率达到 70 % .用元素分析、 IR和 13 C NMR对共聚物进行表征 ,所得共聚物为交替结构     

磺化苯乙烯-马来酸酐共聚物

磺化苯乙烯-马来酸酐共聚物是由苯乙烯-马来酸酐共聚物直接磺化并中和成钠盐制备。由于它分子中含有很多磺酸及羧酸负离子,因此,是一很好的阴离子聚电解质,被广泛用于泥浆稀释剂、水泥添加剂和皮革鞣剂等。     

低相对分子质量苯乙烯-马来酸酐交替共聚物的合成

将引发剂偶氮二异丁腈(AIBN)、共聚单体苯乙烯(St)和马来酸酐(MA)溶解于甲苯中,采用沉淀聚合法合成苯乙烯-马来酸酐共聚物(SMA).分别研究了反应温度、引发剂用量、反应时间、单体配比和单体浓度对聚合物得率和酸酐含量的影响.采用正交实验确定最优反应条件为:单体浓度20%,单体物质的量比为1∶1,引发剂用量为0.60%,反应温度为86℃,反应时间2h,产物得率为86.86%,酸酐含量为50.28%.并利用傅里叶变换红外光谱(FTIR)、核磁共振碳谱(~(13)C NMR)、凝胶渗透色谱(GPC)和热分析法分别研究聚合物的分子结构、相对分子质量及相对分子质量分布和热稳定性.结果表明产物是苯乙烯-马来酸酐交替共聚物,相对分子质量分布较窄,具有良好的热稳定性.     

苯乙烯-马来酸酐共聚物中酸酐含量测定方法研究

苯乙烯-马来酸酐共聚物（SMA）分子结构中含有酸酐官能团,易于化学改性得到新型功能高分子,在生物以及化学方面均表现出优异特性,而酸酐含量是影响其性能的重要因素,因此必须准确分析共聚物中酸酐含量。本文首先对SMA水溶液进行pH值滴定,确定了SMA在pH值突跃范围内以一元羧基／一元羧酸钠的形式存在,利用微商法确定该范围内pH滴定终点,建立了一种简便、快速确定酸酐含量的pH值滴定方法,并经元素分析验证了该方法测定结果的准确性。     

稀土配位催化马来酸酐-苯乙烯-N-苯基马来酰亚胺三元共聚合

采用稀土配位催化剂研究了马来酸酐、苯乙烯和N 苯基马来酰亚胺的三元共聚合反应 .考察了Al La物质的量的比、不同稀土元素、催化剂浓度、聚合反应时间、单体配比等因素对共聚合反应的影响 .利用核磁、红外、热分析等方法对共聚物进行了初步的表征     

热重法测定高马来酸酐含量苯乙烯-马来酸酐共聚物的组成

高马来酸酐含量苯乙烯-马来酸酐共聚物(SMA)是一种具有优良耐热性、刚性和尺寸稳定性的新型高分子材料.由于SMA分子中含有极性很强、反应活性很高的酸酐官能团,所以它被广泛应用于涂料、粘合剂的改性剂、地板抛光的乳化剂、复合材料和颜料的分散剂、水处理剂等领域[1-5].     

苯乙烯—马来酸酐自由基共聚反应：（Ⅱ）苯乙烯—马来酸酐聚合反应机理

简要地综合苯乙烯－马来酸酐共聚反应机理和数学模型研究和进展。在一定程度上络合－解离模型更能说明苯乙烯－马来酸酐共聚过程。     

COORDINATION COPOLYMERIZATION OF STYRENE WITH MALEIC ANHYDRIDE BY RARE-EARTH COORDINATION CATALYSTS

The study on coordination copolymerization of styrene (S) with maleic anhydride (MA) by rare-earth coordination catalysts, NdL_3-Al(i-Bu)_3, has been successfully carried out for the first time. Some features, kinetic behavior, and mechanism of the SMA copolymerization by Nd(naph)_3-Al(i-Bu)_3 system are described and discussed. The copolymex of styrenemaleic anhydride prepared by the NdL_3-Al(i-Bu)_3 systems in benzene at 50℃ is an alternating-rich white powder having high number-average molecular weight of 6—8.5×10~5. The overall activation energy for the polymerization was found to be 10.5KJ/mol. The polymerization was not suppressed by addition of hydroquinone. The catalytic activity of various ligands in NdL_3 for the copolymerization decreases in the following order: Nd (naph)_3>Nd-(P_(507))_3～NdCl_3-6H_2O>Nd(P_(204))_3>Nd(acac)_3. 3H_2O. The experimental results are explained based on a mechanism to be the coordination-type copolymerization in terms of the participation of a monomer-monomer c     

CONTROLLED RADICAL COPOLYMERIZATION OF STYRENE AND MALEIC ANHYDRIDE UNDER GAMMA RADIATION IN THE PRESENCE OF BENZYL DITHIOBENZOATE

The copolymerization of styrene (St) with maleic anhydride (MAh) under gamma radiation at room temperature inthe presence of benzyl dithiobenzoate (BDTB) was found to display "living" nature evidenced by constant concentration ofchain radicals during the copolymerization, linear evolution of molecular weights with conversion and narrow molecularweight distribution (M_w/M_n = 1.23-1.35). The compositional analysis and the sequence structural information of thecopolymers obtained from DEPT (Distortionless Enhancement by Polarization Transfer) experiments demonstrate that thecopolymers obtained also possess strictly alternating structure.     

马来酸酐-苯乙烯熔融接枝聚丙烯的影响因素及其性能研究

用单螺杆挤出机制备了马来酸酐 (MAH) 苯乙烯 (St)对聚丙烯 (PP)的多组分单体自由基熔融接枝体系 .研究证实了当两种单体物质的量比约为 1∶1时 ,接枝物的接枝率最高 ,而熔体流动速率 (MFR)最大 .对反应体系影响因素的研究表明单体用量和引发剂用量对不同单体用量比的系列接枝物的接枝率会产生不同的影响 ;另外 ,单体用量增加 ,接枝物的MFR减小 ,过氧化二异丙苯 (DCP)用量增加 ,接枝物的MFR增加 .对多单体熔融接枝聚丙烯PP g (MAH co St)的力学性能研究发现 ,选用合适的单体用量比、单体用量和DCP用量时 ,所制备的接枝物可具有与纯PP相当或更佳的力学性能     

NON-LINEAR LEAST SQUARE CURVE FITTING OF COPOLYMERIZATION MODELS TO THE ALTERNATING TRIAD FRACTION OF COPOLYMERS OF STYRENE AND CITRACONIC ANHYDRIDE,AND COPOLYMERS OF STYRENE AND MALEIC ANHYDRIDE PREPARED IN N,N-DIMETHYLFORMAMIDE

Copolymers of styrene (ST) and citraconic anhydride (α-methylmaleic anhydride) (CA) were prepared in a very polar solvent, N,N-dimethylformamide (DMF), at 50.0°C with AIBN. The monomer unit triad fractions were determined by ¹³C NMR in acetone-d ₆ solution. Non linear least square (NLLS) curve fitting was performed for the copolymerization models of the terminal model, the penultimate unit effect model, the complex participation model, the complex dissociation model, and the so-called comppen model. The theoretical equations for the ST-centered alternating triad mole fraction were fitted by NLLS minimization routine to the triad fraction data of the ST-CA copolymers and that of the ST-maleic anhydride (MA) copolymers prepared in identical polymerization conditions. It was found that for rigidly alternating copolymers of ST-MA, the difference among the copolymerization models disappeared and all models merged together. The difference among the copolymerization models were somewhat more apparent for less alternating copolymers of ST-CA copolymers. The sum of squares values indicated that the copolymerization models, which involved some complex participation, fit the data better with the comppen model. This was a combination of a complex participation and penultimate unit effects, which performed best.     

FREE-RADICAL-INITIATED COPOLYMERIZATION OF 2-CHLOROSTYRENE, 4-CHLOROSTYRENE,AND 2,6-DICHLOROSTYRENE WITH MALEIC ANHYDRIDE

The title copolymers have been prepared by the free-radical-initiated copolymerization of 2-chlorostyrene (2-ClSt), 4-chlorostyrene (4-ClSt) and 2,6-dichlorostyrene (2,6-DClSt) with maleic anhydride (MAn) in toluene at 65°C. Copolymers of chlorinated styrenes with MAn prepared under different monomer-to-monomer ratios in the feed have alternating composition. In all cases, the mixture of comonomers forms charge-transfer complex monomers (CTC). The initial rate of copolymerization increases with the increase of electron donors in the comonomer feed, and the highest rates were at the equimolar ratios of comonomers in the feed. The thermal stability of the polymers was measured by thermogravimetric analysis in nitrogen. Homopolymers decompose by a one-step mechanism, while copolymers are more thermostable and decompose by a two-step mechanism. Glass transition temperatures (T_gs) of homopolymers are lower than T_gs of copolymers. The number and weight average molecular weights of chlorinated copolymers are higher than those of the corresponding homopolymers.     

马来酸酐和苯乙烯的可逆加成-断链链转移聚合及新型嵌段共聚物的合成

马来酸酐和苯乙烯是被广为研究的一对电荷转移复合物 (Ｃｈａｒｇｅｔｒａｎｓｆｅｒｃｏｍｐｌｅｘ,简称ＣＴＣ) ,而且能通过通常的自由基聚合发生交替共聚[1] .所得的聚合物由于酸酐基团的存在 ,很易进行大分子改性得到具有某些特殊功能的高分子 .不过 ,所得共聚物的分子量难以控制且分子量分布也较宽 .近年来发展起来的“活性” 可控自由基聚合越来越为人们所关注 ,因为采用这种方法不仅可对聚合物的分子量进行设计 ,同时分子量分布也较窄 ,也不需要活性离子型聚合那样严格的聚合条件 .关于烯类单体的活性自由基聚合迄今主要有氮氧自由基…     

Nd(naph)3-Al(i-Bu)3催化邻苯二甲酸酐与环氧丙烷交替共聚

Ｎｄ（ｎａｐｈ）３Ａｌ（ｉＢｕ）３催化邻苯二甲酸酐与环氧丙烷交替共聚房江华黄士力（宁波师范学院化学系，宁波３１５０２０）沈之荃（浙江大学高分子科学与工程学系，杭州３１００２７）关键词环烷酸钕，交替共聚，邻苯二甲酸酐，环氧丙烷分类号Ｏ６４３／ＴＱ３...     

烷基硫醇诱发苯乙烯马来酸酐共聚合的研究

<正> 硫醇由其上S—H弱键易遭受自由基进攻而用作调聚剂是熟知的。硫醇作为氧化-还原体系的一个组成促进丁苯乳液聚合也有报道,但单独硫醇,在相当于引发剂的用量范围内及常温条件下,诱发烯类单体或CTC(电荷转移络合物)型单体对的共聚报道极少。我们发现了微量硫醇在常温下对苯乙烯(St)、马来酸酐(MAn)共聚的催化效应,并