乳液聚合中的反应型乳化剂研究进展

介绍了反应型乳化剂的最近研究进展,并简述了其结构、分类和特点。探讨了可聚合乳化剂应用效果的几个影响因素和最佳可聚合乳化剂行为。对设计和使用可聚合乳化剂具有一定的指导作用。     

苯乙烯反应挤出聚合过程的实验研究

在SHL-φ35型紧密啮合同向旋转双螺杆挤出反应器中采用活性聚合引发体系,进行了苯乙烯反应挤出合成聚苯乙烯的研究。用静态实验法对一组螺杆结构的填充度分布和粘均分子量沿螺杆轴向分布进行计算。同时对单体在挤出反应器中的聚合过程进行了研究,提出了在活性聚合体系下,反应挤出合成聚苯乙烯两段聚合过程机理。     

聚合型受阻酚抗氧剂的研究进展

综述了以双环戊二烯、对甲苯酚和异丁烯为原料生成聚合型受阻酚抗氧剂CPL的反应机理、国内外文献报道的典型制备方法及应用情况。指出了聚合型受阻酚抗氧剂的发展趋势,强调了应加强此类抗氧剂的研究。     

负载钛催化丁二烯-异戊二烯共聚合反应动力学的研究

研究了TiCl4 /MgCl2 负载型高效催化剂催化丁二烯 -异戊二烯共聚合的动力学特征 ,并对影响聚合速率的因素进行了考察。首先通过计算排除了扩散控制对反应总聚合速率的影响 ,测定了单体浓度和催化剂浓度的反应级数和表观活化能 (2 2 .8kJ/mol) ,建立的聚合速率方程为 :R =kp·f·[Ti]·[M]。     

固体酸催化合成聚合松香甘油酯

研究用负载型固体酸催化聚合松香和甘油的酯化反应，探讨了反应温度、催化剂用量、甘油用量、甘油加入方式等因素对酯化效率的影响，选择适宜的反应条件。     

聚合型色素的开发与进展

一、前言聚合型色素是一类崭新的有机化合物。其结构特点是在色素母体上含有烯基、羟基、氨基或羧基等,能与其它可聚合单体或预聚体进行加成共聚或缩合共聚反应。与以往的活性染料相似,聚合型色素是通过共价键与被着色分子结合而获得优异性能。但两者反应历程不同,聚合型色素的反应属     

反应型防老剂对丁腈橡胶聚合反应的影响

以丁二烯和丙烯腈为聚合单体,添加反应型防老剂进行自由基乳液聚合实验,考查了防老剂的种类和用量对聚合反应、乳液及聚合物性质的影响。结果表明,反应型防老剂对丁腈橡胶的聚合反应有抑制作用;在所选用的3种反应型单体中,NAPM热氧稳定性最好。NAPM较适宜的用量为1.75%。     

Lewis酸改性烷基锂负离子聚合研究进展Ⅰ.烷基锂负离子聚合现状及改性

介绍了烷基锂负离子聚合工艺存在的主要弊端,同时指出适当降低高反应速率的途径是调控活性种的反应性。阐述了Lew is酸改性烷基锂负离子聚合的研究进展,认为酸根型络合物反应性和选择性的设定是调控活性负离子聚合的关键,是研发新型负离子引发体系的重要内容。     

EVA型柴油低温流动性能改进剂的研制

制备了EVA型柴油低温流动性能改进剂,对影响聚合过程的四个主要因素——聚合压力、反应温度、引发剂含量以及醋酸乙烯酯含量分别进行了考察,获得了其影响聚合产物粘度、酯含量和降低冷滤点效果的规律;同时利用XRD和DSC初步探讨了该降凝剂的降凝机理。     

Hypol工艺用BCZ-108H型催化剂的聚合行为

研究了丙烯聚合用BCZ-108H型催化剂在60～85 ℃时的聚合行为及所制聚丙烯的主要性能,并与Hypol工艺常规应用的NA型催化剂和市售催化剂进行了对比。结果表明:随着温度的升高,丙烯聚合反应速率和催化剂活性总体呈降低趋势,且聚合反应速率的衰减越来越快。在整个温度区间内,采用BCZ-108H型催化剂的聚合反应速率和活性远高于另外两种催化剂,温度为70 ℃时,3种催化剂用于丙烯聚合的反应速率和活性的差距最小;温度为80 ℃时,3种催化剂用于丙烯聚合的反应速率和活性的差距最大。     

“饥饿”反应器中苯乙烯聚合动力学

本文对“饥饿”反应器中ＡＩＢＮ引发苯乙烯聚合行为进行了详细的研究，建立了相应的聚合动力学模型，在模型中，考虑了由于初级自由基与单体反应生成单体自由基时所消耗的单体量，并将链终止速率常数与聚合物的累积数均链长进行校正。利用实验数据对模型参数进行了回归。     

“饥饿”反应器中自由基聚合动力学(Ⅱ)──甲基丙烯酸甲酯聚合动力学

对“饥饿”反应器中甲基丙烯酸甲酯（MMA）聚合行为进行详尽研究,建立了聚合动力学模型,模型中考虑了由于初级自由基与单体反应生成单体自由基时所消耗的单体量;考虑了PMMA的高温解聚作用;考虑了体系中的凝胶效应,并将链终止速率常数与凝胶效应联系起来,反映在模型中．通过实验,优化回归求取了模型参数．     

KINETICS OF RADICAL POLYMERIZATION IN A STARVED FEED REACTOR (Ⅱ)──KINETICS OF METHYLMETHACRYLATE POLYMERIZATION

对“饥饿”反应器中甲基丙烯酸甲酯（MMA）聚合行为进行详尽研究,建立了聚合动力学模型,模型中考虑了由于初级自由基与单体反应生成单体自由基时所消耗的单体量;考虑了PMMA的高温解聚作用;考虑了体系中的凝胶效应,并将链终止速率常数与凝胶效应联系起来,反映在模型中．通过实验,优化回归求取了模型参数．     

The plasma polymerization of vinyl monomers. II. A detailed study of the plasma polymerization of styrene

A study has been made on the plasma polymerization of styrene monomer in a cold, low-power, inductively coupled RF plasma. Styrene monomer yielded an insoluble, crosslinked film which was slightly colored. A kinetic study is reported for styrene. The effects of power level, bleed rate of monomer, pressure, and reactor geometry on the rate of polymer formation are reported. A mechanism is postulated for plasma polymerization. It was found that the initiation step was the rate controlling step and that the reaction followed a cationic polymerization scheme. Both crosslinking and discoloration of the polymers occur at the time of polymerization and are not a result of exposure of the reacted polymer to the plasma. The polymerization was shown to take place in the bulk phase as well as on the reaction wall surfaces.     

Experimental investigation of vinyl chloride polymerization at high conversion—reactor dynamics

A series of suspension polymerizations of vinyl chloride monomer (VCM) was carried out in a 5-L pilot plant reactor over the temperature range, 40–70°C. The reactor pressure and monomer conversion were monitored simultaneously every 7–8 min. The critical conversion X_f, at which the liquid monomer phase is consumed, was considered to occur when the reactor pressure fell to 98% of the vapor pressure of VCM for suspension at the polymerization temperature. The reactor model predictions of pressure are in excellent agreement with the experimental data over the entire conversion and temperature ranges studied. The mechanism of reactor pressure development for VCM suspension polymerization is discussed herein in some detail. For isothermal batch polymerization, the reactor pressure falls in two stages due to the effect of polymer particle morphology on pressure drop. The first stage is due to the volume increase of the vapor phase as a result of volume shrinkage due to conversion of monomer to polymer. The monomer phase is not yet consumed at this stage, but it is trapped in the interstices between primary particles creating a mass transfer resistance; therefore, the reactor pressure drops slowly. The second stage is due to both the volume increase of the vapor phase and to the monomer in the vapor phase diffusing into the polymer phase because of the subsaturation condition with respect to monomer in the polymer phase. The reactor pressure drops dramatically with an increase in monomer conversion at this stage. The present model can be used to predict reactor dynamics during suspension polymerization under varying temperature and pressure conditions.     

丁二烯气相聚合过程中的单体吸附效应和本征动力学模型

采用负载型稀土催化剂 ,在搅拌床反应器内进行丁二烯气相聚合动力学的研究 .考察了单体在聚合物小粒子中的吸附效应和单体压力与温度对聚合速率影响 ,在此基础上 ,提出了本体系的本征动力学模型     

丙烯/1-丁烯聚合物合金的单体组成切换法制备：动力学及聚合器模型

采用球形负载型Ziegler-Natta催化剂和单体组成周期性切换的丙丁淤浆共聚合技术,原位制备了聚丙烯/丙丁共聚物合金。将共聚动力学的矩模型与物料衡算相结合,首次建立了单体组成切换的共聚反应器模型。依据实验所得的丙烯实时消耗速率拟合得到模型参数,并模拟计算了不同单体组成切换频率下的聚合反应活性和聚合产物的组成。结果表明,模型能很好地描述各切换频率下丙烯的聚合速率曲线、催化聚合活性,以及合金中1-丁烯的总含量、丙丁无规共聚物的含量和“嵌段”共聚物的含量等。结果还显示,共聚过程中丙烯的脉冲进料有利于提高单体向活性中心的扩散,进而提高聚合速率和聚合活性。     

Effect of multiple feeds on a termination-free polymerization in continuous stirred tank reactors

The effect of monomer and initiator feeds to each of a series of continuous stirred tank reactors (CSTR) on the molecular weight distributions, average molecular weight, polymer production rate, and initiator and monomer conversions is studied for the termination-free polymerization system. For initiator feed concentrations less than 0.001 mole/liter, the distribution becomes narrower as the polymer progresses from reactor 1 to reactor 3. But for concentrations of initiator of 0.01 mole/liter, the distribution may be broadened from reactor 1 to reactor 3. The broadening of the distribution results in the production of a lower molecular weight polymer.     

球形TiCl4/MgCl2催化剂引发丙烯气相聚合动力学

采用微机在线控制的半连续烯烃聚合反应器,在加压条件下进行了球形TiCl₄/MgC_l2催化剂催化的丙烯气相聚合,测定了单体瞬时聚合速率等重要的动力学数据,考察了不同聚合条件对聚合动力学的影响,并用Flory-Huggins方程估算了聚合物非晶区中的单体浓度C_m.研究表明聚合速率与C_m成正比;丙烯聚合速率在反应一开始就迅速衰减,之后是缓慢的衰减.提出了一个n级衰减的丙烯气相聚合动力学模型,根据实验数据拟合得到了模型的各个参数,其中活性中心的衰减级数为2.5,气相聚合的表观增长活化能为77.1 kJ•mol^-1.用该模型可以较好地模拟加压条件下的丙烯气相聚合动力学行为.     

Dispersion Polymerization of Styrene by Initiation Within Monomer Phase with Lauroyl Peroxide

Dispersion polymerization kinetics of styrene was investigated in this study. A monomer phase soluble initiator, namely lauroyl peroxide, and a water phase soluble emulsifier, namely sodium dodecyl sulfate, were used. the polymerizations were carried out in a magnetic drive, sealed, cylindrical polymerization reactor, in nitrogen atmosphere. Two different fatty alcohols, cetyl and lauryl alcohols, were tried as particle size increasing agents. the effects of initiator, emulsifier concentrations, monomer/water ratio, and the weight ratio of particle size increasing agent to emulsifier on the total monomer conversion, average size, and size distribution of the large latex particles were studied. the agglomeration conditions were tested by changing the polymerization temperature, initiator, and emulsifier concentrations. the results indicated that the polymerization rate and the average size of the latex increased with increasing emulsifier concentration. the average size of the latex was also increased with increasing initiator concentration. the use of cetyl alcohol in the presence of emulsifier resulted in an appreciable increase in the polymerization rate and in the average size of the latex. the effect of fatty alcohols on the polymerization rate in the dispersion polymerization system was completely different than that in the swollen emulsion polymerization. the agglomeration of the large latex particles was increased with decreasing emulsifier and increasing initiator concentrations.