甲基丙烯酸甲酯与N-氯苯基马来酰亚胺乳液共聚物研究

采用乳液聚合法制备了不同单体配比的甲基丙烯酸甲酯与N-对氯苯基马来酰亚胺（NCLPMI）共聚物乳液．讨论了单体配比对共聚物孔液的转化率、聚合稳定性、流变性、粒径大小与分布、成膜性能和热性能的影响，并用NMR表征了共聚物的结构。结果表明采用种子滴加法共聚物乳液较稳定．转化率一般高于90％．凝胶百分率低于1％；乳胶粒径随着NCLPMI含量的增加而减小；乳液粘度随着NCLPMI含量增加而降低；随着NCLPMI含量的增大共聚物乳液较易形成表面平滑的膜；共聚物热降解分为两阶段：第一阶段分解温度在170～250℃之间，质量损失率低于6％；第二阶段分解温度在280-440℃之间．质量损失率较高一般可达90％。共聚物的第二阶段初始分解温度随着NCLPMI含量的增加而逐渐提高，而且第二阶段质量损失率也随着NCLPMI含量的增加而降低；通过计算核磁谱图中特征峰的峰面积发现．随着单体中NCLPMI含量的增加．共聚物中NCLPMI含量也增大。     

苯乙烯与N-间甲苯基马来酰亚胺共聚物乳液性能表征

采用种子滴加法合成了苯乙烯与N-间甲苯基马来酰亚胺共聚物乳液,讨论了单体配比对乳液的聚合稳定性、表面张力、流变性、粒径大小及分布、成膜性能的影响。并用DSC和TGA对共聚物耐热性能进行了表征。实验结果表明,随着N-间甲苯基马来酰亚胺含量的增加共聚物的Tg呈明显上升趋势。     

N-苯基马来酰亚胺与苯乙烯共聚物乳液的研究

采用种子乳液聚合法制备了N-苯基马来酰亚胺(NPMI)与苯乙烯(St)共聚物乳液,讨论了单体配比对共聚物乳液的聚合稳定性、转化率、流变性、表面张力、粒径大小及分布的影响。结果表明:随着混合单体中NPMI含量的增加,NPMI与St混合单体的转化率降低,聚合物乳液的凝胶量增大,聚合稳定性减弱,黏度逐渐增加。所得共聚物乳液粒径为70~80nm,粒径分布均匀。     

N-对甲苯基马来酰亚胺乳液共聚物性能表征

通过乳液聚合制得N-对甲苯基马来酰亚胺(NPTMI)、甲基丙烯酸甲酯、苯乙烯的三元共聚物．采用热重分析、维卡软化点测试、差示扫描量热分析等方法研究了不同单体配比共聚物的热性能及力学性能．用凝胶渗透色谱(GPC)测定了共聚物的分子量及其分布。结果表明：加入NPTMI可以有效地提高共聚物的热稳定性,NPTMI质量分数为20％的共聚物与不含NPTMI的共聚物相比．玻璃化转变温度、维卡软化点、热分解起始温度、分解50％时的温度分别提高了22．6,19．5,42．8,46．2℃．但力学性能有所下降。GPC测定结果表明,分子量在合适的单体配比下出现最大值。     

MMA/N-对甲苯基马来酰亚胺乳液共聚的研究

通过乳液共聚得到N－对甲苯基马来酰亚胺（NPTMI）,甲基丙烯酸甲酯（MMA）的二元共聚物,用扭辫分析,热重分析和维卡软化点测定仪研究了不同NPTMI含量对共聚物热性能的影响,以及共聚物的力学性能,流变性能,研究结果表明,共聚物初始分解温度（Tini),失重50％时的温度,玻璃化转变温度（Tg)及维卡软化点（TViout)都随NPTMI的含量增加而提高,当NPTMI含量为15％时,Tg提高14．1℃,Tini提高23．2℃,TVicut提高8．9℃,工聚物熔体呈假塑性流体,同时共聚物熔体非牛顿指数随NPTMI含量的增加而增大。     

甲基丙烯酸甲酯-N-环己基马来酰亚胺二元共聚物的研究

研究了本体法甲基丙烯酸甲酯-N-环己基马来酰亚胺二元共聚体系的组成对共聚物的光学性能、热性能及力学性能的影响。实验结果表明,当-N-环己基马来酰亚胺用量为甲基丙烯酸甲酯量的2．5％时,共聚物的玻璃化转变温度比纯聚甲基丙烯酸甲酯提高了12．3℃;热分解温度提高了41．1℃;硬度及透明性也均有所提高。     

N-对甲苯基马来酰亚胺(NMPMI)/甲基丙烯酸甲酯(MMA)共聚合研究

根据自由基共聚合和交联改性有机高分子材料的原理,以偶氮二异丁腈(AIBN)为引发剂,甲苯为溶剂,N-对甲苯基马来酰亚胺(NMPMI)和甲基丙烯酸甲酯(MMA)为原料,采用溶液聚合法合成了N-对甲苯基马来酰亚胺/甲基丙烯酸甲酯共聚物,并研究了原料配比、引发剂用量、反应时间、温度等工艺条件对产品收率的影响,确定了共聚合反应...     

N-环己基马来酰亚胺／甲基丙烯酸甲酯／苯乙烯乳液共聚物与PVC共混的研究

通过乳液共聚合得到N-环己基马来酰亚胺(ChMI)、甲基丙烯酸甲酯(MMA)、苯乙烯(St)的三元共聚物(ECMS)，用共聚物作耐热改性剂与PVC共混，用TBA和TGA研究了共聚物含量对共混物热性能、力学性能、流变性能及维卡软化点的影响。结果表明随三元共聚物含量的增加，共混物的玻璃化温度及维卡软化点逐渐上升；PVC第一阶段降解完毕。后平台区残留量逐渐上升；拉伸强度提高，冲击强度下降；熔体表观粘度增加，呈假塑性流体。     

甲基丙烯酸甲酯-N-环己基马来酰亚胺-苯乙烯三元共聚物的研究

研究了甲基丙烯酸甲酯-N-环己基马来酰亚胺-苯乙烯三元共聚体系中苯乙烯用量对共聚物的透光性、黄色度、耐热性、物理机械性能及加工流动性的影响。结果表明：在不影响产品透光性的前提下,St的加入可明显降低产品的黄色度;适量的St可提高共聚物的耐热性并改善共聚物的力学性能。苯乙烯的用量为甲基丙烯酸甲酯和N-环己基马来酰亚胺总质量的15％时,可以得到综合性能良好的共聚物。     

苯乙烯/丙烯腈/N-苯基马来酰亚胺的乳液共聚研究

以十二烷基硫酸钠为乳化剂、过硫酸钾为引发剂,通过乳液聚合,合成了苯乙烯-丙烯腈-N-苯基马来酰亚胺三元共聚物(St-AN-PMI),并考察了各单体配比、乳化剂浓度、引发剂浓度等对聚合反应和最后产物的影响.发现该共聚物中PMI的含量是决定其性质的重要因素,而聚合时合适的乳化剂浓度和引发剂浓度分别为13～15 mmol/L和1.8～2.4 mmol/L.     

甲基丙烯酸甲酯-丙烯酸乙酯乳液共聚动力学研究

为了合成适于药物包衣用的甲基丙烯酸甲酯-丙烯酸乙酯(MMA-EA)共聚物胶乳,对以非离子型乳化剂OP-10为乳化剂、过硫酸钾为引发剂的MMA-EA乳液共聚动力学进行了研究。发现初期共聚速率随着乳化剂浓度、引发剂浓度和聚合温度的增加而增大,这是由于共聚物乳胶粒子平均粒径随着乳化剂、引发剂浓度和聚合温度的增加而减小,乳胶粒子数目增加所致。通过调节乳化剂、引发剂以及反应温度可以达到合适的聚合反应速率,最终合成出转化率大于95%的MMA-EA共聚乳液。     

Ultrasound‐assisted emulsion polymerization of methyl methacrylate and styrene

In this article, we report on the effect of using ultrasound during emulsion polymerization. This work differs somewhat from that previously reported in that ultrasound is used in conjunction with conventional initiators. The aim is to observe the changes in the nature of polymerization and the synthesized polymer. In this work, reaction conditions and compositions typical of conventional emulsion polymerization are used. Azo‐bisisobutyronitrile and potassium per sulfate are the initiators used. The initial indication is that the rate of polymerization and the final conversion are higher when ultrasound is introduced into the polymerization system. This effect is more pronounced at lower temperatures (50°C) and low initiator concentrations (0.01%). At higher temperatures (70°C) the polymerization rate is seemingly unaffected by the use of ultrasound. The final product in all the experiments is a latex. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 101–104, 2000     

Iron (II) chloride catalyzed emulsion polymerization of methyl methacrylate using different initiators

The emulsifier and emulsifier-free emulsion polymerization of methyl methacrylate (MMA) using sodium bisulphite, acetaldehyde sodium bisulphite (ACSB), octyladehyde sodium bisulphite (OSB), benzaldehyde sodium bisulphite (BSB), and acetone sodium bisulphite (ASB) as different initiators, and dodecyl benzene sodium sulphonate (DBSS) as an emulsifier, were carried out at 30, 40, and 50°C. The effect of iron (II) chloride on the rate of polymerization and on the viscosity-average molecular weight was investigated. The effect of temperature, iron (II) chloride, and the type of initiator on the tacticity of the obtained polymers was investigated by means of nuclear magnetic resonance (NMR) spectroscopy. The effect of iron (II) chloride and the four carbonyl adducts (ACSB, OSB, BSB, and ASB) on the volume-average diameter and the number of polymer particles per unit volume was investigated. It was found that iron (II) chloride has a pronounced catalytic effect on the emulsion polymerization. The initiating powers of the four carbonyl adducts, ACSB, BSB, OSB, and ASB, were found to be 3.27, 0.6, 1.78, and 0.23, respectively. The rate of emulsion polymerization and viscosity-average molecular weight were found to be dependent on the emulsifier concentration, initiator type and concentration, temperature, and amount of the catalyst (FeCl₂). © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1725–1738, 1998     

Factorial experimental design approach in semicontinuous emulsion polymerization of methyl methacrylate to study the effect of process variables

This article describes the effect of various process variables in the semicontinuous emulsion polymerization of methyl methacrylate. A series of poly(methyl methacrylate) (PMMA) emulsions were prepared using ammonium persulphate as initiator in absence and presence of Dowfax 2AI as surfactant. The effect of process variables such as initiator concentration, monomer concentration (solid content), surfactant concentration, reaction temperature, monomer feeding time, and holding time were systematically studied on monomer conversion, particle size, gel content, and molecular weight using a two‐level fractional factorial experimental method. Analysis of fractional factorial design revealed that surfactant concentration, monomer concentration, initiator concentration, and monomer feeding time affect all the properties. However, the surfactant concentration and the interaction effect of initiator and monomer feeding time are the key variables influencing the properties of PMMA latex. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

丙烯酸高级酯共聚物组成与其无皂乳液稳定性研究

制备了不同分子结构的丙烯酸高级酯共聚物无皂乳液,测定了丙烯酸和甲基丙烯酸十六酯的竟聚率,考察了共聚物的组成对无皂乳液电解质稳定性、机械稳定性和pH值稳定性的影响。结果显示,丙烯酸竟聚率为2.32,甲基丙烯酸十六酯竟聚率为0.59,随共聚物中丙烯酸组分含量增加,乳液粒子表面羧基含量增大,乳液机械稳定性和pH值稳定性提高,乳液适合在偏碱性条件下使用。     

氯乙烯-丙烯酸丁酯-甲基丙烯酸甲酯三元共聚物的研究

讨论了氯乙烯 丙烯酸丁酯 甲基丙烯酸甲酯三元共聚物 3种共聚单体的投料比、反应温度、引发剂用量对共聚物树脂性能的影响。所得共聚树脂加工成片后 ,测量其各种物理性能 ,结果显示出低温韧性和抗冲击性等有了明显提高。     

EA-MMA共聚乳液合成工艺及优化

以丙烯酸乙酯(EA)和甲基丙烯酸甲酯(MMA)为共聚单体、过硫酸钾(KPS)为引发剂、十二烷基硫酸钠(SDS)和壬基酚聚氧乙烯醚(OP-10)为复合乳化剂,采用乳液聚合法合成出一种稳定的EA-MMA乳液。通过单因素试验法考察了乳化剂浓度、引发剂浓度、反应温度和反应时间等因素对乳液平均粒径和单体转化率的影响,并采用正交试验法进一步优选出制备EA-MMA乳液的最佳工艺条件。结果表明:当w(乳化剂)=2.0%、w(引发剂)=0.60%、反应时间为4 h和反应温度为80℃时,制成的EA-MMA乳液较稳定,并且单体转化率相对最高。     

Different composition poly(methyl methacrylate-co-butyl methacrylate) copolymers through seeded semi-batch emulsion polymerization

In the present work the synthesis and the chemical and thermal characterization of poly(methyl methacrylate-co-butyl methacrylate) copolymer, in three different macromolecular compositions, are reported. The aim of the present work was the identification of a standard method to obtain copolymers with controlled macromolecular composition, molecular weights and particle size distribution, together with the identification of the effect of the macromolecular composition on the material properties. A monomer-starved seeded semi-batch emulsion reaction was carried out and optimized, monitoring the kinetic of the copolymerization through the evaluation of residual monomer amounts. Then, an evaluation of the macromolecular composition was performed by Fourier transform infrared spectroscopy analysis. Molecular weight, molecular weight distribution, latex characteristics and thermal behaviour were also investigated.