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以十二烷基硫酸钠/十二烷基苯磺酸钠(SDS/SDBS)为乳化剂,过硫酸钾/亚硫酸钠(K2S2O3/Ni2SO3)为引发剂进行苯乙烯/丙烯酸丁酯(SL/BA)微孔液共聚合反应。研究了引发剂浓度[I]OR、单体总浓度[M]、乳化剂含量[E]和聚合温度T对微孔液共聚合最大反应速率Rmax和共聚物粘均分子量^-Mη的影响,测定了共聚单体的竞聚率,结果得到:Rmax∝[I]^0.98OR[M]^0.81[E]^-0.34e^-4712/T,^-Mη∝[I]^-0.27OR[M]^0.48[E]^-0.68e^2304/T;rSt=0.598,rBA=0.0206。 相似文献
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通过实验绘制了失水山梨醇单月桂酸酯(Span20)-聚氧乙烯山梨醇酐单脂酸酯(Tween80)复配乳化剂、丙烯酰胺、(2-甲基丙烯酰氧乙基)三甲基氯化铵、2-丙烯酰胺基-2-甲基丙基磺酸钠和环己烷的拟三元相图.采用过硫酸铵-亚硫酸氢钠氧化还原引发剂,通过动力学研究,得到了聚合反应的表观活化能为68.10 kJ/mol,并分别得到了聚合速率与产物特性粘数的动力学关系式Rp∝[M]1.74[APS]0.60[E]-1.28,[η]∝[M]0.78[APS]-0.23[E]-0.71,分析了单体浓度、引发剂浓度、乳化剂浓度对共聚合反应速率Rp和共聚物特性粘数[η]作用及影响的原因,在动力学研究的基础上初步探讨了聚合机理. 相似文献
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聚氨酯一聚丙烯酸酯共聚乳液的合成研究 总被引:4,自引:0,他引:4
以甲基丙烯酸β-羟乙酯封端的聚氨酯大分子单体与丙烯酸酯类单体进行乳液共聚,合成了以聚丙烯酸酯(PA)为主链、聚氨酯(PU)为侧链的接枝共聚物(PA-g-PU)乳液,用IR光谱和^1H NMR光谱对该聚氨酯大分子单体及PA-g-PU接枝共聚物进行了表征,并对影响聚氨酯-聚丙烯酸酯共聚合的因素进行了探讨。结果表明:聚氨酯大分子单体的加入对乳液聚合的速率造成较大的影响。该体系的表观活化自由能为99.39KJ/mol,Rp∝[I]^0.87,Rp∝[S]^0.12。 相似文献
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(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺反相微乳液共聚合研究 总被引:14,自引:0,他引:14
采用SPAN-OP复合乳化剂和K_2S_2O_8-Na_2SO_3氧化还原引发剂,进行(2-甲基丙烯酰氧乙基)三甲基氯化铵-丙烯酰胺的反相微乳液共聚合。测得单体的竞聚率r_(DM·MC)=1.11±0.16,r_(AM)=0.53±0.08。在单体总浓度为20—40%(wt),引发剂浓度为0.01—0.05%,乳化剂浓度为10—18%,聚合温度为299K的条件下,得到共聚反应动力学方程:R_p=k[M]~(1.07)[I]~(0.52)[E]~(0.90),文中对上述结果做了解释。 相似文献
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VAC与甲基丙烯酰氧乙基三甲基氯化铵无皂乳液共聚合动力学研究 总被引:3,自引:0,他引:3
研究了醋酸乙烯酯 (VAC)与甲基丙烯酰氧乙基三甲基氯化铵 (DMC)无皂乳液共聚合动力学 ,考察了引发剂偶氮二异丁基脒盐酸盐 (AIBI)浓度、单体浓度、温度等因素对聚合反应速率的影响 ,得到单体总浓度和引发剂浓度影响反应速率的动力学方程为 :Rp=k1 [M]0 6 3[AIBA]1 0 ;各单体浓度影响反应速率的动力学方程为 :Rp=k2 [VAC]0 1 6 [DMC]0 89.聚合表观活化能为 4 4 0 1kJ·mol- 1 ,初步探讨了聚合反应机理 . 相似文献
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反相乳液共聚合制备两性丙烯酰胺共聚物的研究 总被引:3,自引:0,他引:3
采用Span80-Tween80复合乳化剂和AIBA引发剂,进行丙烯酸钠(NaAA)/丙烯酰胺(AM)/丙烯酰氧基乙基三甲基氯化铵(DAC)反相乳液共聚合.研究了聚合温度、引发剂用量、单体浓度、共聚单体中DAC和AM含量、乳化剂用量及其HLB值、水/油比和水相pH值等聚合反应工艺条件或参数对聚合反应单体转化率和聚合物特性粘度的影响,聚合物特性粘度随引发剂用量和单体浓度的增大而增大的实验结果证实了该两性丙烯酰胺共聚物反相乳液制备过程中凝胶效应的存在.傅立叶红外光谱组成分析表明了两性丙烯酰胺共聚物的成功合成,扫描电镜观测乳胶粒粒径范围在0.6~8.0μm. 相似文献
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反应性乳化剂存在下半连续苯丙乳液共聚合表观动力学 总被引:1,自引:0,他引:1
研究了在反应性乳化剂SE-10N存在下,采用半连续滴加工艺进行苯丙乳液共聚合的表观动力学.首先利用间歇法研究了引发剂、乳化剂用量、单体总量和温度对聚合反应速率的影响,得到了相应的聚合反应速率方程为Rp =k[M]0.30[I]0.18[E]0.97,并计算得到聚合反应的表观活化能为90.8 kJ·mol-1.然后采用半连续滴加法,讨论了不同滴加速率对聚合表观速率Rp的影响,结果表明,随滴加速率Ra 的增加,反应速率Rp也增加,但增加的幅度逐渐减少,且聚合过程的状态不断远离饥饿态.要使该聚合过程的状态保持在稳定的饥饿态,单体滴加时间应控制在140 min 以上. 相似文献
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Cline Farcet Julien Nicolas Bernadette Charleux 《Journal of polymer science. Part A, Polymer chemistry》2002,40(24):4410-4420
The controlled free‐radical homopolymerization of n‐butyl acrylate was studied in aqueous miniemulsions at 112 and 125 °C with a low molar mass alkoxyamine unimolecular initiator and an acyclic β‐phosphonylated nitroxide mediator, N‐tert‐butyl‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl) nitroxide, also called SG1. The polymerizations led to stable latices with 20 wt % solids and were obtained with neither coagulation during synthesis nor destabilization over time. However, in contrast to latices obtained via classical free‐radical polymerization, the average particle size of the final latices was large, with broad particle size distributions. The initial [SG1]0/[alkoxyamine]0 molar ratio was shown to control the rate of polymerization. The fraction of SG1 released upon macroradical self‐termination was small with respect to the initial alkoxyamine concentration, indicating a very low fraction of dead chains. Average molar masses were controlled by the initial concentration of alkoxyamine and increased linearly with monomer conversion. The molar mass distribution was narrow, depending on the initial concentration of free nitroxide in the system. The initiator efficiency was lower than 1 at 112 °C but was very significantly improved when either a macroinitiator was used at 112 °C or the polymerization temperature was raised to 125 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4410–4420, 2002 相似文献
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Kevin M. Burridge Nethmi De Alwis Watuthanthrige Camryn Payne Richard C. Page Dominik Konkolewicz 《Journal of polymer science. Part A, Polymer chemistry》2021,59(21):2530-2536
An enduring question is: what is the simplest and easiest way to obtain tailored polymers? This communication explores a robust photoiniferter polymerization with only two active ingredients that requires no prior deoxygenation and can be performed on the milliliter scale or sub-milliliter scale. Rather than leaving headspace in the polymerization vessel or scaling reactions up to fill the vessel, this approach fills the headspace of the reaction vessel with mineral oil or inert solvents. This approach can also be applied to polar monomers in aqueous media, using oil as the inert solvent, or to hydrophobic monomers with water as the inert solvent. This method removes enough ambient oxygen that the photoiniferter reaction proceeds with no deoxygenation step, and achieves high conversion and good molecular weight control in 10–20 h in both aqueous and organic solvents. Complex polymer architectures such as multiblock copolymers and gradient polymers were successfully synthesized by this approach. 相似文献
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原子转移自由基聚合(ATRP)应用于乳液聚合体系的主要挑战在于如何同时保证乳液的稳定性和聚合反应的可控性。本文主要对乳液ATRP体系中影响聚合反应可控性和乳液稳定性的各种因素、乳液ATRP的机理和乳液ATRP的应用等方面进行了综述。表面活性剂亲水亲油性及其亲水亲油基团的化学性质、催化剂/配体在油/水两相之间的分配行为、引发剂的溶解性、反应温度以及各组分的浓度是影响反应可控性和乳液稳定性的主要因素。各组分在油/水两相中的分配行为使得乳液ATRP的机理比传统乳液聚合更加复杂。乳液原子转移自由基聚合结合了活性自由基聚合和乳液聚合的优点,在理论研究和工业生产上具有很大的应用前景。 相似文献
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Reverse iodine transfer polymerization (RITP) is a new controlled radical polymerization technique based on the use of molecular iodine I2 as control agent. This paper aims at presenting the basics of RITP and the strategy that we have followed for the development of this process in the past three years, from the validation in homogeneous solution polymerization up to recent results in heterogeneous aqueous polymerization processes. Typical examples of RITP of butyl acrylate in emulsion and RITP of styrene in miniemulsion are discussed. 相似文献
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Xiaohong Liu Dr. Michael G. Debije Dr. Johan P. A. Heuts Prof. Dr. Albert P. H. J. Schenning 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(57):14168-14178
Liquid-crystalline polymer particles prepared by classical polymerization techniques are receiving increased attention as promising candidates for use in a variety of applications including micro-actuators, structurally colored objects, and absorbents. These particles have anisotropic molecular order and liquid-crystalline phases that distinguish them from conventional polymer particles. In this minireview, the preparation of liquid-crystalline polymer particles from classical suspension, (mini-)emulsion, dispersion, and precipitation polymerization reactions are discussed. The particle sizes, molecular orientations, and liquid-crystalline phases produced by each technique are summarized and compared. We conclude with a discussion of the challenges and prospects of the preparation of liquid-crystalline polymer particles by classical polymerization techniques. 相似文献