三烯丙基异氰酸尿酯－二乙烯苯－醋酸乙烯大孔共聚物的合成及其醇解反应

根据文献查得的Ｑ、ｅ值，计算了三烯两基异氰酸尿酯－二乙烯苯－醋酸乙烯三元共聚体系的竞聚率，预测了它们进行共聚的可能性．以甲苯和汽油为致孔剂，采用悬浮聚合的方法合成了此三元大孔共聚物，并研究了致孔剂用量、交联度等对共聚物孔性能的影响。实验发现，此共聚体系在适当条件下，可以制得很高比表面积的大孔共聚体，比表面积可高达１２１４ｍ２／ｇ。对合成的共聚物又进行了醇解反应，得到了含羟基的共聚体。     

三磷丙基异氰酸尿酯—二乙烯苯—醛酸乙烯大孔共聚物的合成及…

根据文献查得的Ｑ，ｅ值，计算了三烯丙基异氰酸尿酯－二乙烯苯－醋酸乙烯三元共聚体系的竞聚率，预测了它们进行共聚的可能性。以甲苯和汽油为致孔剂，采用悬浮聚合的方法合成了此三元大孔共聚物，并研究了致孔剂用量，关联度等对共聚物孔性能的影响。实验发现，此共聚体系在适当条件下，可以制得很高比表面积的大孔共聚体，比表面积可高达１２１４ｍ＾２／ｇ。对合成的共聚物又进行了醇解反应，得到了含羟基的共聚体。     

HEMA-NVP-St三元共聚体系研究Ⅲ.均化剂对共聚物组成均一性的影响

用溴化钾-溴酸钾滴定法测定双键含量,元素分析法测定共聚物组成。讨论了HEMA-NVP-St三元共聚体系在不同反应程度时共聚物组成的变化,以及在此三元共聚体系中引入均化剂后,少量均化剂对共聚体系组成均一性的影响。发现在HEMA-NVP-St三元共聚体系中加入均化剂,对共聚反应的反应动力学影响不大,但对共聚物的组成均一性有较大影响。它的加入使三元共聚物中的链节比分布(即不同反应程度时,产物的累积平均组成)向较均一的方向发展。结合红外光谱、电子显微镜等实验证据,从微观结构上探讨了约化剂的作用。阐明均化剂改善了反应体系的相容性,从而得到组成分布较为均一的共聚产物。     

丙烯腈,丙烯酸甲酯,衣康酸三元共聚竞聚率的测定

本文主要论述三种单体以不同配比在硫氢酸钠水溶液中进行共聚合，探讨其反应规律，用电子计算机由三元共聚组成方程求出了反应体系中三个单体的六个竞聚率，建立了配料组成、共聚物的组成及计算的竞聚率之间的关系，并对三元共聚竞聚率进行了分析。     

顺丁烯二酸二丁基锡-苯乙烯-丙烯酸丁酯三元共聚物的结构与性能表征

采用本体聚合的方法，在氧化苯甲酰（BPO）存在下，合成了顺丁烯二酸二丁基锡－苯乙烯－丙烯酸丁酯（DBTM－St-BA)三元共聚物，用GPC，FTIR，1H NMR，TG和刚果红法及布拉本热流变仪对共聚产物的结构和性能进行了有征，结果表明，在所选定的聚合条件下，共聚产物为DBTM－St-BA的三元共聚物，在含锡量相同的情况下，共聚物对PVC的热稳定效果和加工性能的影响优于DBTM，可以作为多功能化的PVC热稳定剂。     

N—苯基马来酰亚胺／苯乙烯／丙烯腈共聚合体系的研究

测定了６０℃下Ｎ－苯基马来酰亚胺在苯溶剂中分别与苯乙烯,丙类腈共聚的二元竞聚率,并据此估算其三元共聚物组成,研究表明,实验值和计算值较为接近,如果适当控制混合单体比例和反应条件,可望得到组成较均一的共聚物。     

核磁共振法测定苯乙烯和甲基丙烯酸正丁酯竞聚率的研究

以苯乙烯（Ｓｔ）－甲基丙烯酸正丁酯（ＢＭＡ）共聚体系为研究对象，在共聚单体组成敏感点附近做重复实验，进行了４０、６０、８０、１００，１２０、１４０℃下的共聚合，用ＮＭＲ方法测定共聚物的组成，用Ｍａｙｏ－Ｌｅｗｉｓ微分组成方程的误差变量法计算竞聚率，同时给出竞聚率的９５％可信椭圆区间．并根据竟聚率对温度的依赖关系得到一组合理的竞聚率值．     

St/BA/KH-570三元共聚物的合成及其在云母增强聚丙烯中的应用

通过原子转移自由基聚合反应，合成了苯乙烯，丙烯酸丁酯和3－甲基丙烯酰氧基丙基三甲氧基硅烷的三元共聚物，发现该共聚合体系是一“活性”／受控聚合体系，三元共聚物的结构通过红外光变和核磁共振得以确认。研究了该三元共聚物作为大分子偶联剂对云母增强聚丙烯力学性能的影响。发现三元共聚物的组成和分子量对云母增强聚丙烯的力学性能有较大影响。     

以丙烯为主体的二元及三元共聚研究——丙烯与乙烯和丁烯—1的共聚合

研究了ＭｇＣｌ２载体高效催化剂用于丙烯为主体的与乙烯和丁烯－１的二元及三元共聚合反应：选择最佳了共聚合条件；实验测定了共聚单体配比对共聚合活性，共聚物分子量和物理性能的影响；并用＾１３Ｃ－ＮＭＲ分析了共聚物组成、序列分布和支链结构等微观结构信息。     

甲基丙烯酸甲酯-苯乙烯-N-苯基马来酰亚胺三元共聚物的研究

研究了甲基丙烯酸甲酯-苯乙烯-N-苯基马来酰亚胺三元共聚体系的组成以及分子量分布对共聚物的耐热及物理机械性能的影响.实验结果表明:在一定条件下如果适当控制混合单体比例,可望获得一种综合性能较优越的共聚物材料.     

α-甲基苯乙烯与苯乙烯阴离子共聚合研究——Ⅱ.共聚组成及单体表观竞聚率

 本文研究了以正丁基锂为引发剂、四氢呋喃为极性添加剂,在环己烷中进行α-甲基苯乙烯与苯乙烯阴离子共聚合。通过共聚组成及聚合活性种研究,由反应机理推导了该体系的共聚组成方程,求得了不同[THF]下的表观竞聚率值r₁和r₂。     

α-甲基苯乙烯与苯乙烯阴离子共聚合研究——Ⅱ.共聚组成及单体表观竞聚率

本文研究了以正丁基锂为引发剂、四氢呋喃为极性添加剂,在环己烷中进行α-甲基苯乙烯与苯乙烯阴离子共聚合。通过共聚组成及聚合活性种研究,由反应机理推导了该体系的共聚组成方程,求得了不同[THF]下的表观竞聚率值(?)和(?)。     

全氟甲基乙烯基醚和其它含氟单体乳液共聚合的竞聚率测定

分别通过气相色谱法测定了全氟甲基乙烯基醚 (PMVE)与偏氟乙烯 (VDF)以及PMVE与四氟乙烯(TFE)二元乳液共聚反应中的气相单体组成和共聚物组成 ,然后用非线性回归法 (RREVM )计算得TFE PMVE及VDF PMVE乳液共聚合反应的表观竞聚率分别为γTFE =3 89和γPMVE =0 0 5以及γVDF =1 0 6和γPMVE =0 11.结合已经测定的TFE VDF二元乳液共聚的表观竞聚率 ,计算了由VDF TFE PMVE三元乳液共聚合反应合成的共聚物组成 ,后者与由1 9F NMR实测的共聚物组成吻合     

Estimation of reactivity ratios using emulsion copolymerization data

An approach for the estimation of reactivity ratios using cumulative copolymer composition–overall conversion data obtained in batch emulsion copolymerization is presented. The approach is based on an algorithm for parameter estimation in ordinary differential equations and takes into account the partition of the comonomers between the different phases present in the system. Both copolymer composition and conversion were considered to be affected by experimental errors. The method was first checked by using simulated data that included random errors. The effect of the initial guess and level of errors on the values of the estimated reactivity ratios was investigated. Once the approach was checked, it was used to estimate the reactivity ratios of the styrene–acrylonitrile system based on data obtained in unseeded batch emulsion copolymerizations of these monomers.     

丙烯酸甲酯/4-丙烯酰胺基-2,2,6,6-四甲基哌啶光共聚合体系的竞聚率和序列分布研究

以丙烯酸甲酯(MA,M1)和4-丙烯酰胺基-2,2,6,6-四甲基哌啶(AATP,M2)溶液光共聚合体系为研究对象,采用1H-NMR手段测定了MA/AATP共聚物的组成,用Mayo-Lewis积分法和扩展Kelen-Tüdos方法计算的竞聚率分别为0.88相似文献   

Estimation of Reactivity Ratios from Multicomponent Copolymerizations

Abstract

The composition of the copolymer formed from n monomers in addition polymerization can be expressed in terms of the monomer feed composition and n(n - 1) binary reactivity ratios, according to the familiar simple copolymer model. Reactivity ratios are determined experimentally from cor-responding feed and monomer compositions in binary co-polymerizations. This article reports methods for deriving such reactivity ratios directly from multicomponent polymerization data. Analytical solution of the multi-component copolymer equations is not feasible because of the limited number of experimental points and experimental uncertainty in the copolymer composition. Computer-assisted procedures have been developed to estimate re-activity rates by optimizing the fit of predicted and experimental copolymer compositions, given the monomer feed composition and preliminary values of the reactivity ratios. All n(n - 1) reactivity ratios are adjustable. The methods are demonstrated for styrene/methacrylonitrile/ a-methylstyrene, butadiene/styrene/2-methyl- 5-vinyl- pyridine and acrylonitrile/methyl methacrylate/& methylstyrene systems. Binary reactivity ratios predict ternary copolymer compositions generally well in these cues. Reasons are suggested why reactivity ratios from multicomponent experiments may not match the corresponding parameters from binary copolymerizations.     

Estimation of monomer reactivity ratios by nonlinear least-squares procedure with consideration of the weight of experimental data

To obtain the optimum values of the monomer reactivity ratios for the copolymerization systems with largely different reactivities between both monomers, a nonlinear least-squares procedure which took into account the weights of experimental data, was proposed and discussed. The weights of the data were treated for the errors arisen from the amounts of monomers charged, the densities of monomers, the weights of copolymer formed, and the composition of copolymer. The least-squares procedure with the consideration of the weights was applicable to both differentiated equation and integrated equation derived by Lewis and Mayo. This procedure was applied to radical copolymerizations of α-substituted crotonic esters with styrene, and reasonable monomer reactivity ratios were obtained. It was noted that errors from the copolymer composition were more important than those from the other factors and that the use of the integrated equation was recommended even when the copolymers were isolated at low conversions.     

Bulk Free‐Radical Co‐ and Terpolymerization of n‐Butyl Acrylate/2‐Ethylhexyl Acrylate/Methyl Methacrylate

n‐Butyl acrylate (BA), 2‐ethylhexyl acrylate (EHA), and methyl methacrylate (MMA) are commonly used monomers in pressure‐sensitive adhesive formulations. The bulk free‐radical copolymerizations of BA/EHA, MMA/EHA, and BA/MMA are studied at 60 °C to demonstrate the use of copolymer reactivity ratios for the prediction of BA/MMA/EHA terpolymer composition. The reactivity ratios for BA/EHA and MMA/EHA copolymer systems are determined using low conversion experiments; BA/MMA reactivity ratios are already known from the literature. The reactivity ratio estimates for the BA/EHA system are r _BA = 0.994 and r _EHA = 1.621 and the estimates for MMA/EHA are r _MMA = 1.496 and r _EHA = 0.315. High conversion experiments are conducted to validate the reactivity ratios. The copolymer reactivity ratios are shown to predict terpolymer composition of high conversion BA/MMA/EHA experiments.     

Electroinitiated copolymerization of indene and α-methylstyrene

Electroinitiated cationic copolymerization of indene and α-methylstyrene in dichloromethane has been investigated by constant potential electrolysis. The effects of copolymerization potential and the temperature on the copolymer composition was also studied. Constant potential electrolysis was found to be a suitable method to study the potential effects on copolymer compositions and the reactivity ratios of the monomers. The reactivity ratios were calculated according to integrated Lewis–Mayo equation.