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乳液聚合的最新进展(上) 总被引:21,自引:0,他引:21
本文对近10多年中发展起来的与乳液聚合相关的聚合技术,如无皂乳液聚合、细乳液聚合、微乳液聚合、分散聚合等,也对其实施方法、理论研究结果和应用作了介绍;还针对近年来已经成为热点的核壳乳液、单分散聚合物微球及表面官能化的乳液微球的制备方法及应用进行了综述。 相似文献
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纯化对三元无皂共聚胶粒性质的影响 总被引:1,自引:0,他引:1
以离子交换和高速离心两方法纯化含不同功能基的三元无皂共聚胶乳,用TEM和电导滴定检测比较了以上两方法的纯化效果,同时考察了这两种纯化方法对三元无皂胶粒形态,大小及表面功能其量的影响。研究发现,只有通过多次离心-倾析-再分散过程才能将胶乳所有杂质除去。离子交换和离心纯化不影响胶粒形态大小,而离心纯化使粒表面功能其量发生显著变化。 相似文献
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丙烯酸钠反相浮液聚合 总被引:3,自引:0,他引:3
以阴离子乳化剂制备丙烯酸钠反应相乳液,用γ射线引发其聚合,用扫描电镜观测了聚合前后粒径的变化;并在聚合过程中改变剂量率观测了聚合速率的变化,这两个实验结果都显示聚合以液滴成核为主,即聚合机理类似于悬浮聚合,与以司盘80为乳化剂的丙烯酸钠反相乳液聚合相比,体系与司盘体系的聚合动力学基本相似。 相似文献
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MMA—St无皂乳液聚合成核机理探讨 总被引:5,自引:0,他引:5
讨论了MMA-St无皂乳液聚合,当[KPS]=2.77×10~(-3)mol/L,[MMA]0.51mol/L,[St]=0.49mol/L,70℃反应5.0小时,能得到较高的聚合转化率,较小的胶乳粒径和较大的粒子浓度,并对不同反应时期聚合物的分子量及其分布进行了测定,认为该无皂乳液聚合体系为均相沉淀成核机理。当转化率大于30.9%时,胶乳粒的凝聚程度大于胶乳粒的生成速度。KPS分解产生的自由基起到了稳定乳液的作用。 相似文献
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苯乙烯—丙烯酸丁酯无皂乳液聚合动力学及TEM分析 总被引:2,自引:1,他引:2
讨论了温度对十一烯酸钠存在下的苯乙烯、丙烯酸丁酯无皂乳液聚合体系pH值的影响,描述了聚合反应动力学曲线,求出不同温度下的聚合反应速率常数.利用TEM对几种乳化剂体系的乳液聚合进行比较后发现,在无皂乳液聚合体系中,乳胶粒的均匀性和粘连、形变等都得到了控制.由于体系中不存在游离乳化剂,乳液的稳定性得到提高. 相似文献
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研究了MMA-St在氧化还原引发剂KPS-CuSO_4-Na_2SO_3存在下的快速无皂乳液聚合.当[MMA]=0.51mol/L、[St]=0.49 mol/L、70℃对,在[KPS]=2.77×10~(-3)mol/L、[CuSO_4]=1.50×10~(-5)mol/L、[Na_2SO_3]=2.77×10~(-3) mol/L条件下反应100min,转化率大于90%;讨论了胶乳的分子量及其分布;求出了聚合反应活化能E_a=81.6 kJ/mol和聚合反应速率常数k_p=321.9 L/mol·s. 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