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偏氯乙烯/丙烯腈/苯乙烯悬浮共聚合动力学 总被引:1,自引:0,他引:1
本文研究了偏氯乙烯(VDC)/丙烯腈(AN)/苯乙烯(St)三元悬浮共聚合体系的聚合机理、共聚速率、非聚物组成及其特性粘度的影响因素。实验表明随着投料配比的改变,可分成四个不同聚合机理区域。St对VDC/AN/St三元悬浮共聚有缓聚作用。VDC三元悬浮共聚速率可用半经验模型,dC/dt=αC^β「Ⅰ」o^γexp(-γkdt)描述,由实验得到模型参数γ值为2.24,模型参数α、β是聚合温度与引发剂浓度的函数。VDC-AN-St三元悬浮共聚物存在着较宽的VDC组成分布,并受到单体AN水溶性的影响,经AN动态相平衡校正后,可预测VDC三元共聚物组成。VDC-AN-St共聚物的特性粘度随着转化率的升高而增大。在相同引发剂用量下,高转化率VDC-AN-St共聚物特性粘度的对数与温度的倒数成线性关系。 相似文献
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考察了超声波辅助甲基丙烯酸(MAA)和丙烯腈(AN)共聚合时,单体配比、引发剂浓度、超声波频率以及超声场温度对体系转化率的影响。结果表明,超声波能够辅助MAA/AN进行本体聚合,加快聚合反应速率。超声波辐照下,本体聚合的转化率随反应温度的升高而增大,引发剂用量为0.2%时,反应的转化率最大。外加能量的超声波利于加快聚合反应速率,在频率为24 kHz的超声波辐照下,对提高共聚反应转化率的作用最大。 相似文献
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1丙烯腈聚合的特点[1,2]在水溶性引发剂诱导下,丙烯腈的悬浮聚合,其起始阶段,聚合引发、链增长先是在水相中进行,当反应活性链增长到8~10个链节时,原先的均相体系开始混浊,出现相分离,活性长链分子开始从水中析出,但仍继续增长,逐步形成最初一级约(5... 相似文献
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本文报导了二氧化碳(CO2)和环氧丙烷(PO)、丙烯酸甲酯(MA)在PBM型聚合物负载双金属催化剂作用下,在比较温和的条件下的共聚反应,以及反应条件对共聚的影响。产物经红外光谱(IR)、核磁共振(NMR)、差示扫描量热法(DSC)、热重分析法(TGA)分析表明为三元共聚物,其热性能优于聚碳酸亚丙酯。 相似文献
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Hossein Hosseinzadeh 《应用聚合物科学杂志》2009,114(1):404-412
The polysaccharide, kappa carrageenan (kC), was modified using ceric‐initiated graft copolymerization of acrylonitrile (AN) under inert atmosphere in a homogeneous aqueous medium. Grafting was confirmed using FTIR spectroscopy, solubility test, elemental analysis, acid hydrolysis, and thermogravimetric analysis (TGA). kC‐graft‐poly(AN) products had a higher thermal stability than kC as revealed by TGA analysis. The polyacrylonitrile branches were isolated by acidic degradation of the carrageenan main chains and characterized by size exclusion chromatography (SEC). Residual monomers were not found by HPLC in graft copolymers stored even for longer periods. The effect of various factors affecting on grafting, i.e., concentration of the initiator, monomer, and polysaccharide as well as the reaction time and temperature were studied by conventional methods to achieve the optimum grafting parameters. The graft copolymerization reactions were kinetically investigated using semi‐empirical expressions and a suitable rate expression has been derived. According to the empirical rates of the polymerization and the graft copolymerization of AN onto kC backbone, the overall activation energy of the graft copolymerization reaction was estimated to be 20.96 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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G.D. Verros 《Polymer》2003,44(22):7021-7032
An effective method for calculating molecular weight distribution in non-linear free radical copolymerization is proposed in this work. This method is based on the direct integration of a system of non-linear differential equations describing the conservation of ‘dead’ polymer and ‘live’ radicals in a reactor. A fairly general kinetic mechanism was employed to describe the complex kinetics of non-linear copolymerization. Assumptions made were justified by comparing calculated distributions with results obtained without making any assumption. This method may be applied to industrial free radical polymerization systems, thus leading to a more rational design of polymerization reactors. 相似文献
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探讨以正庚烷 /甲苯混合物为溶剂 ,采用共聚法制备EPDM接枝聚苯乙烯 丙烯腈 (EPDM g SAN)的反应条件。试验得出的优化反应条件为 :单体苯乙烯 /丙烯腈质量比 3 /1,EPDM/单体质量比 45 /5 5 ,引发剂BPO浓度 3 3 8× 10 - 3mol·L- 1 ,正庚烷 /甲苯体积比 60 /4 0 ,反应温度 80℃ ,反应时间 2 0h。在此条件下 ,反应的单体转化率、接枝率和接枝效率分别为 75 % ,3 3 %和 3 6%。红外光谱分析证明 ,EPDM分子链上接枝了SAN支链 相似文献
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采用悬浮共聚的方法研制了偏氯乙烯/丙烯酸甲酯(VDC/MA)共聚树脂。考察了共聚配方、分散剂种类及用量、搅拌速度及聚合温度对VDC/MA共聚树脂的影响。结果表明,当VDC/MA=(92-96)/(8-4)、采用分散剂B(用量0.13%)、搅拌速度300-400r/min,并根据聚合温度调节分子量大小,制得的VDC/MA共聚树脂其膜光泽好、透时度高,热稳定性好。 相似文献
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过硫酸铵引发丙烯腈/衣康酸铵的共聚合工艺研究 总被引:3,自引:0,他引:3
选择衣康酸铵[(NH4)2IA)]作为共聚单体,以过硫酸铵[(NH4)2S2O8]为引发剂,采用水相沉淀聚合工艺合成高分子质量的丙烯腈/衣康酸镀[AN/(NH4)2IA)]共聚物。研究了引发剂浓度、单体浓度、单体配比、聚合温度和聚合时间对共聚反应的影响。结果表明:该体系的聚合反应速率较快,且制得了粘均分子质量高达(38-75)×104的AN/(NH4)2IA共聚物。 相似文献
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A generalized copolymerization rate equation is proposed. The North equation of copolymerization is a special case that can be derived from the generalized equation. According to the mass balance and charge-transfer complex (CTC) equilibrium equation, the free monomer concentration is differentiated from the feed monomer concentration. The effects on the copolymerization rate (the equilibrium constant, total monomer concentration, homopropagation constants, and reactivity ratios) are quantitatively calculated and discussed. The generalized equation may be applied to not only the systems with the participation of CTC, such as styrene/N-phenylmaleimide (PMI), but also those without the participation of CTC, such as methyl methacrylate/PMI. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2635–2639, 1999 相似文献
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Acrylonitrile/ammonium itaconate [AN/(NH4)2IA] aqueous deposited polymerizations were studied in this work. It shows that the polymerizations were influenced by various factors, especially the water solubility of AN. In the polymerization process, the system was as separated monomer and water phases, and AN transferred from monomer phase to water phase until the monomer phase disappeared. Because of the solubility of AN in water, the reactivity ratios of monomer calculated by Kelen‐Tudos method were different in various monomer contents. Although (NH4)2S2O8 was a water‐soluble initiator, there was a short amount of polymer formed in monomer phase. To inhibit the polymerization in monomer phase, two additives were used in the polymerization and experiment data indicated that the two inhibitors exert inhibitory role effectively in monomer phase. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 904–908, 2006 相似文献