偏氯乙烯/丙烯腈/苯乙烯悬浮共聚合动力学

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。     

超声波辅助引发MAA/AN自由基共聚合研究

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。     

丙烯腈悬浮共聚合反应釜的设计

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...     

DC/AN悬浮共聚树脂的组成及其特性研究

研究了偏氯乙烯／丙烯腈悬浮共聚树脂的组成,玻璃化曙度Ｔｇ、熔融焓△Ｈｍ、结晶度Ｘｃ和溶解度参数δｐ。结果表明：虽然ＡＮ的竞聚率较大,但ＶＤＣ／ＡＮ悬浮共聚树脂中ＡＮ含量却低于原料单体中ＡＮ的含量。、熔融     

聚合物负载双金属催化剂催化CO2—PO—MA共聚

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。     

淀粉在CH3OH-H2O溶液中与MA进行接枝共聚的研究

在ＣＨ３ＯＨ－Ｈ２Ｏ溶液中,以过硫酸铵作引发剂进行淀粉与丙烯酸甲酯的接枝共聚反应,测定了共聚物接枝链的粘均相对分子质量、接枝效率、接枝频率,扫描电镜与力学性能。     

聚丙烯腈原丝纺丝溶液的合成

以偶氮二异丁腈 (AIBN)为引发剂 ,研究了丙烯腈与丙烯酸甲酯在二甲基亚砜溶剂中的自由基均相溶液共聚合反应。考察了单体浓度、引发剂浓度、单体配比 ,反应温度和时间等对共聚反应的影响。分别用称重法和乌氏粘度计测定了反应的转化率和产物的相对分子质量。研究结果表明 ,制备高性能聚丙烯腈纺丝溶液最佳的反应条件是 :总单体浓度2 5 % ,AIBN占总单体浓度 1% ,反应温度为 6 0℃ ,时间为 30h     

Ceric‐initiated free radical graft copolymerization of acrylonitrile onto kappa carrageenan

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     

Calculation of molecular weight distribution in non-linear free radical copolymerization

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.     

EPDM-g-SAN接枝共聚反应的研究

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     

偏氯乙烯-丙烯酸甲酯悬浮共聚树脂的研制

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。     

木薯淀粉/VAc-MA接枝共聚物的合成研究

通过正交试验设计,研究醋酸乙烯酯和丙烯酸甲酯两种单体接枝改性木薯淀粉的影响因素。利用SAS统计分析得出适宜的工艺条件:引发剂浓度16mmol.L-1,总单体浓度1.45mol.L-1,两单体配比(VAc/MA)为30/70,反应温度65℃,反应时间5h。采用红外光谱对该接枝共聚物结构进行了分析。     

过硫酸铵引发丙烯腈／衣康酸铵的共聚合工艺研究

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。     

Novel generalized rate equation for free radical copolymerization

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     

Acrylonitrile/ammonium itaconate aqueous deposited copolymerization

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     

接枝共聚改性氯化聚丙烯乳液的研究

以丙烯酸酯单体作为接枝共聚单体,合成了无芳烃低VOC的CPP(氯化聚丙烯)乳液。以接枝率和耐水性作为衡量指标,采用单因素试验法优选出制备CPP乳液的最佳工艺条件。结果表明:当反应温度为95℃、反应时间为3.5 h、w(总引发剂)=1.0%(其中10%引发剂在滴加单体以前加入,并且间隔时间为10 min)、w(丙烯酸酯单体)=30%和w(丙烯酸)=5%时,相应CPP乳液的综合性能相对较好,并且其对聚丙烯(PP)基材的附着力相对最好。