Synthesis and characterization of polystyrene/layered double‐hydroxide nanocomposites via in situ emulsion and suspension polymerization

Polystyrene (PS)/ZnAl layered double‐hydroxide (LDH) nanocomposites were synthesized via in situ emulsion and suspension polymerization in the presence of N‐lauroyl‐glutamate surfactant and long‐chain spacer and characterized with elemental analysis, Fourier transform infrared spectrum, X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis. The XRD and TEM results demonstrate that the exfoliated ZnAl–LDH layers were well dispersed at molecular level in the PS matrix. The completely exfoliated PS/LDH nanocomposites were obtained even at the 20 and 10 wt % LDH loadings prepared by emulsion polymerization and suspension polymerization, respectively. The PS/LDH nanocomposites with a suitable amount of LDH showed apparently enhanced thermal stability. When the 50% weight loss was selected as a comparison point, the decomposition temperature of the exfoliated PS/LDH sample prepared by emulsion polymerization with a 5 wt % LDH loading was about 28°C higher than that of pure PS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3758–3766, 2006     

The role of radical polymerization in the production of thermoregulating microcapsules or polymers from saturated and unsaturated fatty acids

The microencapsulation of linoleic (LinA), oleic, erucic, and palmitic acids (PAs) from styrene and divinylbenzene were studied by using the suspension‐like polymerization technique. All materials exhibited a spherical shape, with a particle size between 166 and 416 μm. The phase change material (PCM) content decreased with the presence of double bonds in the fatty acid molecule. The thermal energy storage (TES) capacity of the microcapsules (MC) containing saturated PA was the highest (123.30 J g^?1). Whereas, the lowest TES capacity was observed for the LinA. TES capacity values from unsaturated fatty acid materials and the high particle yield indicated that these kinds of acids played two different roles, as PCM and also as monomers, in the radical polymerization processes. At high initiator concentrations, the unsaturated fatty acids were observed to react. This was confirmed by Fourier transform infrared where the peak assigned to the C?C bond disappears in the spectrum of MC. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45970.     

种子乳液聚合在PUA合成中的应用

系统地概述了种子乳液聚合合成聚氨酯－聚丙烯酸酯（PUA）复合乳液研究的各个方面，包括研究开发背景、基本原理，制备方法和工艺，产物和涂膜的结构和性能等。     

Synthesis and properties of styrene–butylacrylate emulsion copolymers modified by silane compounds

Styrene (St)/butyl acrylate (BA) copolymers were prepared by adding triethoxyvinylsilane (TEVS), trimethoxyvinylsilane (TMVS), and triphenylvinylsilane (TPVS), each one through emulsion copolymerization. The polymerization was performed with methacrylic acid and auxiliary agents at 80°C in the presence of potassium peroxodisulfate as the initiator. Nonylphenol ethylene oxide‐40 units (NP‐40) and sodium lauryl sulfoacetate were used as nonionic and anionic emulsifiers, respectively. The resulting copolymers were characterized by using Fourier transform infrared spectroscopy. Thermal properties of the copolymers were studied by using thermogravimetric analysis and differential scanning calorimetry. The morphology of copolymers was also investigated by optical microscopy, and then the effects of silicone kinds and concentrations on the properties of the St/BA emulsion copolymers were discussed. The obtained copolymers have high solid content (50 %) and can be used in emulsion paints as a binder. The comparison of three different vinyl silanes indicates that the TEVS influences on the copolymer properties more than the others. The calculations of monomer conversion and monomer conversion versus time histories indicate that by increasing the silicone concentration, the polymerization rate decreases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of monosultap-polyurethane microcapsules in an inverse emulsion through interfacial polymerization

In this study, we prepared monosultap microcapsules in an inverse emulsion through interfacial polymerization for the first time. The microcapsules are spherical pellets with intact and smooth shell and have a narrow particle size distribution with an average size of about 2.35 μm. More importantly, our microcapsules have excellent thermal stability with a starting decomposition temperature of 233.1 °C, high encapsulation efficiency of 81.9% as well as long-term slow release of monosultap under different conditions. In addition, the shell of the microcapsules can degrade completely in the natural condition, avoiding the pollution to the environment. It can be believed that our microcapsules will show good service performance if employed in agricultural industry. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48594.     

无皂乳液聚合反应机理和制备方法的研究进展

介绍了无皂乳液聚合的反应机理,包括成核机理和核增长机理;概括了无皂乳液聚合的方法及最新研究进展。     

乳液聚合方法研究进展

乳液聚合方法具有各方面的优点和广泛的应用范围,因此,受到人们的广泛关注。本文介绍了乳液聚合的优缺点,并着重介绍了一些新的乳液聚合方法及其原理、特点、应用以及中外最新的一些研究成果。     

Synthesis and characterization of fluoropolymer modified polyacrylate in emulsion polymerization

A novel method to produce fluorine‐containing polyacrylate emulsion is presented. It is prepared by the copolymerization of n‐methyl methacrylate, n‐styrene, n‐butyl acrylate, and α‐methacrylic acid in the presence of swollen particles of PTFE. The structure and properties of the polymers are characterized by GPC, PSD, SEM, and XPS. The number‐average molar mass (Mn) 51,332, and the polydispersity 5.8688 are obtained. The mean diameter of latex particles is 300nm. Scanning electron microscopy reveals that particles of the emulsion are well dispersed. Meanwhile, the F_1S content of the surface on the latex membrane is 8.99%. It is shown that the method of mixing micron and nanometer‐sized particles should be made the next step of research. It is also proved that inertia polymers can be used in emulsion property modification. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 558–562, 2006     

磷酸酯表面活性剂在乳液形成中的应用

用乳液聚合的方法描述了烷基醇(酚)醚磷酸酯作为基本阴离子型乳化剂在形成涂料或胶粘剂用乳液中的功能.研究发现,盐状态下的磷酸酯在乳液聚合中是高效的基本阴离子型乳化剂,它们可以提供典型的粒径控制、低凝胶量以及良好的乳液稳定性;在乳胶粒子形成过程中,得到最佳效果的烷基醚磷酸酯乳化剂中EO的范围为6 mol～9 mol,并且乳液的冻融稳定性与作为磷酸酯中不纯物质的非离子量有关.     

氯乙烯-丙烯腈共聚物乳液合成技术及其表征

介绍了氯乙烯-丙烯腈共聚物的乳液聚合方法,研究了合成过程中乳化剂、引发剂的加入方式及工艺条件对共聚物性能的影响,并对共聚物进行了表征。结果表明:乳化剂的最佳投加方式为(以乳化剂/VCM表示):先投加0.02,反应开始后流加0.02;引发剂的最佳投加方式为(以引发剂/VCM表示):先投加0.012,反应开始后流加0.012。该共聚物具有优良的阻燃性能。     

原位乳液聚合法制备改性蒙脱土及其表征

通过原位乳液聚合的方法制备改性蒙脱土,在聚合之前,可聚合的小分子先接枝到蒙脱土的表面或层间,然后加入苯乙烯单体引发聚合,使聚合物大分子接枝到蒙脱土的表面和层间。十六烷基三甲基溴化铵(CTAB)在乳液聚合改性蒙脱土的过程中既是插层剂又是乳化剂。X射线衍射分析表明,经过处理引入了CTA+和PS大分子使得层间距扩大;红外、热重法分析表明,小分子和大分子已接枝到蒙脱土上。蒙脱土的存在影响了聚合反应动力学,并就小分子的影响作了简单的讨论。     

乳液聚合法聚丙烯酸树脂的制备研究

介绍了以丙烯酸、苯乙烯、丙烯酸丁酯、丙烯酸羟丙酯为单体,采用过硫酸铵作为引发剂,以非离子乳化剂聚氧乙烯醚(OP-10)和阴离子乳化剂十二烷基硫酸钠(SDS)作为复合乳化剂,经过乳液聚合,制得了一种水性涂料用缔合型增稠剂.考察了丙烯酸单体含量、乳化剂用量对乳液性能和增稠剂黏度的影响.优化了反应条件,反应过程和最终乳液都很...     

聚合工艺对丙烯酸酯乳液胶粘剂性能的影响

主要研究了聚合工艺对丙烯酸酯乳液胶粘剂性能的影响 通过对乳液胶粘剂的各种性能测试,发现3种聚合方法中,种子乳液聚合法制备的乳液胶粘剂的综合性能较为理想 采用种子乳液聚合法,最佳聚合工艺为:单体的滴加时间4h、聚合温度50℃、搅拌速率80 r/min     

Suspension polymerization based on inverse Pickering emulsion droplets for thermo-sensitive hybrid microcapsules with tunable supracolloidal structures

Polymerization using Pickering emulsion droplets as reaction vessels is being developed to become a powerful tool for fabrication of hybrid polymer particles with supracolloidal structures. In this paper, two kinds of thermo-sensitive hybrid poly(N-isopropylacrylamide) (PNIPAm) microcapsules with supracolloidal structures were successfully prepared from suspension polymerization stabilized by SiO₂ nanoparticles based on inverse Pickering emulsion droplets. SiO₂ nanoparticles could self-assemble at liquid-liquid interfaces to form stable water-in-oil inverse Pickering emulsion. NIPAm monomers dissolving in suspended aqueous droplets were subsequently polymerized at different temperatures. The hollow microcapsules with SiO₂/PNIPAm nanocomposite shells were obtained when the reaction temperature was above the lower critical solution temperature (LCST) of PNIPAm. While the core-shell microcapsules with SiO₂ nanoparticles' shells and PNIPAm gel cores were produced when the polymerization was conducted at the temperature lower than LCST using UV light radiation. The supracolloidal structures with different cores could be tuned by simply changing reaction temperature, which was confirmed by confocal laser scanning microscopy and scanning electron microscopy. The interesting properties of both microcapsules were their ability of reversibly swelling during drying/wetting cycles and responsive to temperature stimulus. Such functional microcapsules may find applications in double control release system due to the presence of the supracolloidal structures and thermo-sensitivity.     

无机-有机纳米复合乳液的原位聚合及其应用

综述了原位乳液聚合法制备无机．有机纳米复合乳液的技术现状及其形成机理，并运用此技术合成了舍无机纳米粒子的压敏胶用无机-有机纳米复合乳液，分析了纳米粒子在制备过程中的分散性能，从纳米粒子引入方式、乳化剂用量、纳米粒子加入量3方面对压敏胶性能进行考查。     

原位乳液聚合聚苯胺/聚甲基丙烯酸甲酯复合物及其表征

以DBSA为乳化剂和掺杂剂,在水介质中采用原位乳液聚合法制备出了聚苯胺/聚甲基丙烯酸甲酯(PANI/PMMA)复合物。采用扫描电镜、红外光谱分析、紫外光谱分析、热失重分析、X射线光电子能谱分析对PANI/PMMA复合物进行了表征。结果表明:复合物产物粒径在80～120nm;电导率可达到10-2S/cm,接近于乳液聚合得到的DBSA掺杂态PANI;乳化剂DBSA以掺杂剂和稳定剂两种状态存在于复合物中。     

Synthesis of poly(butyl acrylate‐co‐methyl methacrylate)/montmorillonite waterborne nanocomposite via semibatch emulsion polymerization

Poly(butyl acrylate‐co‐methyl methacrylate)‐montmorillonite (MMT) waterborne nanocomposites were successfully synthesized by semibatch emulsion polymerization. The syntheses of the nanocomposites were performed in presence of sodium montmorillonite (Na‐MMT) and organically modified montmorillonite (O‐MMT). O‐MMT was used directly after the modification of Na‐MMT with dimethyl dioctadecyl ammonium chloride. Both Na‐MMT and O‐MMT were sonified to obtain nanocomposites with 47 wt % solids and 3 wt % Na‐MMT or O‐MMT content. Average particle sizes of Na‐MMT nanocomposites were measured as 110–150 nm while O‐MMT nanocomposites were measured as 200–350 nm. Both Na‐MMT and O‐MMT increased thermal, mechanical, and barrier properties (water vapor and oxygen permeability) of the pristine copolymer explicitly. X‐ray diffraction and transmission electron microscope studies show that exfoliated morphology was obtained. The gloss values of O‐MMT nanocomposites were found to be higher than that of the pristine copolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42373.     

Radical ring-opening emulsion polymerization of vinylcyclopropanes

Radical emulsion polymerizations of vinylcyclopropanes, 1,1-bis(ethoxycarbonyl)-2-vinylcyclopropane (ECVCP) and 1,1-dichloro-2-vinylcyclopropane (CVCP) were examined. ECVCP underwent soap-free and soap-in emulsion polymerizations satisfactorily to afford the ring-opened polymer in good yields. Polymer emulsions were obtained in a spherical shape with single particle size distribution. Meanwhile, emulsion polymerization of CVCP proceeded in only a low conversion. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 497–501, 1998     

种子乳液聚合制备MCPU-PMMA复合乳液

本文采用改性蓖麻油合成了软段中含不饱和双键的阴离子聚氨酯水分散液（MCPU），将其作为可聚合乳化剂和种子成分同甲基丙烯酸甲酯（MMA）进行共聚，制得了MCPU－PMMA复合乳液。1HNMR谱图显示MCPU中含有双键结构,共聚后双键消失。通过考察单体转化率和复合乳液平均粒径、凝胶量及成膜耐水及甲苯性探讨了影响种子乳液聚合的多种因素：采用过硫酸钾作为引发剂，单体转化率高，乳液粒径小，成膜耐水及甲苯性好；反应的表观活化能Ea为164.86kJ/mol，反应温度控制在70℃较适宜；聚合反应速率Rp∝［I］1.0856，引发剂用量宜控制在聚合有效组份总质量的0.5％。     

无皂乳液聚合制备PUA乳液的稳定性研究

采用无皂乳液聚合法制备丙烯酸酯一聚氨酯复合乳液（PUA）。HEMA作为交联剂引入到聚氨酯主链上,利用核壳交联制得复合乳液。研究了不同的合成工艺、丙烯酸酯单体、DMPA及HEMA含量,引发剂种类等对乳液稳定性的影响。研究发现,将丙烯酸酯单体溶胀于水性聚氨酯乳液中再进行聚合可大大提高乳液的稳定性;采用1．0％～12％的AIBN为引发剂、DMPA质量分数为4．5％、HEMA质量分数为4．0％～4．5％、丙烯酸酯单体质量分数为30％时,可制得外观及稳定性良好的PUA复合乳液。