Comparison of Approaches to Prepare Polysiloxane-Functionalized Acrylic Latexes

Three methods were used to prepare polysiloxane-functionalized acrylic latexes via emulsion polymerization. Ethyl acrylate and 2-ethylhexyl acrylate were used in all three methods as the acrylic phase. In the first method, an acrylic core was prepared with addition of a coupling agent, 3-(trimethoxysilyl) propyl methacrylate, after which a cyclic siloxane monomer (octamethylcyclotetrasiloxane) was reacted with the coupling agent. In the second method, a silane-terminated polysiloxane (H-PDMS) was reacted with ethylene glycol dimethacrylate, and then copolymerized with ethyl acrylate and 2-ethylhexyl acrylate in a batch emulsion polymerization. In the third method, cyclic siloxane monomer was added during emulsion polymerization of ethyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl methacrylate. Particle size distribution and particle morphology were evaluated using dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. A core-shell morphology was observed in TEM for the first preparation method as proposed. After film formation, surface tension, morphology and dynamic mechanical properties were investigated. Stratification was also examined by Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive X-ray (EDX). Microphase separation was observed by atomic force microscopy (AFM) after polysiloxane modification. Energy dispersive X-ray data indicated that only the second preparation method had a higher silicon content at the film-air interface than film-substrate interface. In all methods, the storage modulus and surface energy of latex films decreased after polysiloxane modification.     

有机硅氧烷改性丙烯酸乳液合成及性能研究

通过乳液聚合法,用羟基硅油与硅烷偶联剂A-151(乙烯基三乙氧基硅烷)或KH-570(γ-甲基丙烯酰氧基丙基三甲氧基硅烷)对丙烯酸酯进行化学改性,借助硅烷偶联剂中的碳碳双键和硅氧烷结构将羟基硅油与丙烯酸酯连接起来。然后利用红外光谱(FT-IR)对改性丙烯酸酯的微观结构进行表征,研究结果表明:Si—O键成功地共聚到了丙烯酸长链中。并对改性后乳液的各项性能进行对比,结果发现通过KH-570改性后的丙烯酸酯乳液在各项性能上都有明显的提升。     

Adhesion performance of PSA–clay nano-composites by the in-situ polymerization and mechanical blending

The synthesis and characterization of acrylic polymer/Na-montmorillonite (Na-MMT) clay nano-composites pressure sensitive adhesives (PSA) are researched. The PSA/clay nano-composites were synthesized by in-situ emulsion polymerization and mechanical blending. And then, different amounts of nanoclay were dispersed in 2-ethylhexyl acrylate (2-EHA)/n-butyl acrylate (BA)/methyl methacylate (MMA)/acrylic acid (AA) monomer mixture, which was synthesized using in-situ emulsion polymerization technique. Morphological observation was carried out using X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). Viscoelastic properties of PSA/clay nano-composites were analyzed using advanced rheometric expansion system (ARES). The adhesion performances of synthesized PSA/clay nano-composites were determined by measurements of peel strength, probe tack and shear adhesion failure temperature.     

原位聚合法制备纳米TiO2/硅丙复合乳液

采用硅烷偶联剂对纳米TiO2进行表面处理，使其亲水性表面改为亲油性，并在其表面接枝上可反应的有机官能团，然后通过原位聚合法与有机硅改性丙烯酸聚合物复合，制得性能稳定的纳米TiO2／硅丙复台乳液。采用透射电子显微镜表征了乳液的结构及其形态。     

色粉纸用自交联丙烯酸树脂乳液的合成及性能

根据色粉纸表面固砂的性能要求,以丙烯酸丁酯(BA)、甲基丙烯酸异辛酯(EHMA)为软单体、丙烯酸甲酯(MA)、甲基丙烯酸甲酯(MMA)为硬单体,丙烯酸羟丙酯(HPA)为交联单体,甲基丙烯酸(MAA)、甲基丙烯酸缩水甘油酯(GMA)作为功能单体,采用半连续种子乳液聚合法,制备了具有核壳结构的水性丙烯酸酯树脂乳液(WSAE-G),进一步将其作为色粉纸表面固砂用黏合剂和成膜剂.讨论了GMA用量对乳液粒径、稳定性和黏度等的影响.利用DLS和TEM对乳液乳胶粒子的大小及形貌进行了表征,使用TG、DSC以及万能材料试验机对胶膜的性能进行了测试.对固砂产品表面进行SEM测试.结果表明:GMA用量为1％(以混合单体总质量为基准,下同)时,乳液粒径为142.4 nm,PDI为0.063,乳液分散稳定指数(TSI)为0.162287.TEM显示,乳液具有清晰的核壳结构.胶膜拉伸强度达9.057 MPa.制得的色粉纸层间结合力为244.9 J/m2,所形成的固砂层均匀、磨砂性较好且不易掉砂.     

有机硅改性丙烯酸酯核-壳乳液的研制

采用种子乳液聚合法，以丙烯酸异辛酯为壳，MMA为核，MAA、K-12和有机硅偶联剂为官能性单体，合成了内硬外软的核-壳型有机硅改性丙烯酸酯乳液。讨论了官能性单体、核-壳单体结构、引发剂等对乳液性能的影响，以及影响乳液聚合的因素。     

天然松香改性苯丙乳液的制备及其性能研究

以苯乙烯(St)、甲基丙烯酸甲酯(MMA)、丙烯酸-2-乙基己酯(2-EHA)、丙烯酸-2-羟基乙酯(HEA)和丙烯酸(AA)为反应单体,利用天然松香乳液作为改性剂,通过乳液聚合的方式制备了松香-苯丙复合乳液。研究了乳化剂用量、引发剂用量、松香乳液用量和单体配比对乳液性能的影响。并通过TGA、DLS、TEM对所制备的复合乳液进行了表征。结果表明:当乳化剂用量为单体质量的5%、引发剂用量为单体质量的0.8%、松香乳液用量为单体质量的30%、m(硬单体)∶m(软单体)=2.5∶1时,制得的乳液呈白色泛蓝光,粒径为131 nm。成膜后,漆膜光滑透明,硬度(1H)、耐水性(接触角97.05°)和附着力(1级)等性能良好。     

原位聚合法制备纳米TiO2/有机硅改性丙烯酸酯复合乳液

用硅烷偶联剂对纳米二氧化钛(TiO2)粒子表面进行预处理，使其表面由亲水性变为疏水性，并在其表面接枝上可反应的有机官能团。通过改性纳米TiO2表面上的原位聚合反应，制备了纳米TiO2／硅丙复合乳液。透射电子显微镜观察结果显示，乳液中存在两种结构的乳胶粒子：一种是以聚丙烯酸酯为核、有机硅聚合物为壳的核壳结构硅丙乳胶粒子；另一种是以纳米TiO2为核、有机聚合物为壳的纳米TiO2／聚合物复合结构乳胶粒子。乳胶粒子的结构形态可由乳化剂的用量控制。该复合乳液具有较好的杀菌效果，在较短时间内对细菌的杀灭率可达90％以上。     

可聚合乳化剂对丙烯酸乳液性能的影响

用甲基丙烯酸甲酯、丙烯酸丁酯及丙烯酸-2-羟丙酯作主单体，丙烯酸作功能单体合成了水性涂料用纯丙乳液，比较了常规乳化剂和可聚合乳化剂对丙烯酸酯乳液性能（包括聚合稳定性，化学稳定性等）的影响，同时用透射电镜观察了粒子形态。结果表明：使用可聚合乳化剂烯丙氧基壬基酚聚氧乙烯（10）醚硫酸铵（DNS-86），能有效改善乳液的性能。     

Investigation on the film surface and bulk properties of fluorine and silicon contained polyacrylate

A series of fluorine and silicon acrylic latexes have been prepared from acrylic monomers, 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) and vinyltriethoxysilane (VTES) via emulsion polymerization. Morphology and particle size distribution were evaluated by transmission electron microscopy (TEM) and dynamic light scattering (DLS) methods. Surface properties of latex films were investigated in terms of ATR-FTIR spectrometry, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water resistance measurement. It is indicated that fluorine content at the surface of fluorosilicone acrylic film decreased as the film forming temperature was increased. A high temperature favored silicon condensation at the film surface, which limited migration ability of fluorine chains. Fluorine segment contributed to surface hydrophobicity while silicon component was beneficial to improve water repellency of the film bulk. Silicon containing particles were more difficult to coalesce than fluorine acrylic particles due to the rigid crosslinked network derived from silanol crosslinking.     

乳液型纸塑复膜胶的研制

以丙烯酸丁酯(BA)和丙烯酸异辛酯(2-EHA)为软单体、醋酸乙烯(VAc)为硬单体和丙烯酸(AA)为功能单体,采用预乳化种子乳液聚合法成功合成了性能优良的醋丙乳液纸塑复膜胶。着重讨论了单体的选择、软硬单体配比、引发剂、乳化剂以及功能单体的用量等因素对乳液性能的影响。研究结果表明:当m(软单体):m(硬单体)=45:50～50:45、w(引发剂)≈0.6%、w(乳化剂)=3.0%和w(功能单体)=6%时,乳液具有较好的纸塑粘接性能。     

Particle coagulation at semicontinuous emulstion polymerization. I. Some factors affecting the process

The factors affecting the amount of coagulum appearing during the semicontinuous emulsion polymerization of acrylic monomers were studied. Monomers were added into the polymerization reactor in the form of emulsion. The stability of the polymerization system was greatly affected by the distribution ratio of a constant amount of emulsifier between the initial charge in the polymerization reactor and the monomer emulsion. The amount of arising coagulum was dependent also on the alkyl length of the alkyl acrylate and increased from ethyl acrylate to 2-ethylhexyl acrylate. The amount of appearing coagulum was essentially decreased by copolymerization with acrylic acid and sulfoethyl methacrylate, respectively. In the case of insufficient covering of particle surface by emulsifier, the colloid stability of polymerizing system was greatly increased by the presence of strong as well as weak acid groups chemically bound on the particle surface.     

The effectiveness of some commercial emulsifiers in emulsion polymerization I. “Soap-free” systems,ethoxylated nonylphenols

The initial polymerization rate of ethyl, butyl, and 2-ethylhexyl acrylate was studied in a thermally insulated polymerization reactor. Monomers were continuously added into the reactor and the effect of variables in emulsifier and initiator concentrations was investigated. Ethyl and butyl acrylate polymerized even in absence of emulsifier. This indicated a homogeneous nucleation of particles. Ethoxylated nonyl-phenols containing 20 and more oxyethylene units were effective in emulsion polymerization of the studied acrylic monomers.     

乙烯基三乙氧基硅烷/丙烯酸酯共聚乳液的研究

以聚丙烯酸丁酯为种子乳液，将乙烯基三乙氧基硅烷（VTES）与丙烯酸酯进行乳液共聚，制成了聚合稳定性良好，性能稳定的有机硅／丙烯酸酯共聚乳液，详细讨论了VTES用量对聚合过程稳定性和乳液粒径大小及分布的影响，采用动态光散射法跟踪了聚合过程的粒径大小及分布，采用TEM表征了粒子形态；同时研究了乳液的粘度及乳胶膜的耐水性能，结果表明：乳胶粒的平均粒径随聚合时间的延长逐渐增大，乳胶粒呈球形，具有核壳结构，随着VTES用量的增加，乳液聚合的稳定性变差，乳胶粒的平均粒均增大，乳液的粘度增加，乳胶膜的吸水率减小。     

聚硅氧烷和丙烯酸酯共聚乳液的研究(Ⅰ)

为了在硅乳种子乳液的基础上进行丙烯酸酯的自由基乳液聚合 ,通过制定正交试验和极差分析 ,讨论了催化剂、带乙烯基的三烷氧基硅烷、丙烯酸等的用量和硬单体 ( MMA) /软单体 ( BA)对乳液聚合稳定性、成膜和涂膜性能等的影响 ,从而得出具有适量的聚硅氧烷含量、聚合和贮存稳定、成膜性好以及涂膜强度好的外墙涂料的基料。     

丙烯酸酯乳液的合成及改性研究

以丙烯酸丁酯(BA)和丙烯酸-2-乙基己酯(2-EHA)为软单体、甲基丙烯酸甲酯(MMA)为硬单体、丙烯酸(AA)为功能单体、甲基丙烯酸羟乙酯(HEMA)为交联单体和十二烷基硫酸钠(SDS)/乳化剂(OP-10)为阴/非离子型复合乳化剂,采用核/壳种子乳液聚合法制备了丙烯酸酯共聚乳液;然后在壳层聚合时寸加入HEMA,并用乙烯基有机硅进行改性,制得硅丙乳液。结果表明:当m(SDS):m(OP-10)=3:2、w(复合乳化剂)=3.4%、w(引发剂)=0.82%、w(HEMA)=3.5%、聚合温度为80℃以及聚合中期加入6.8%乙烯基硅油至壳单体中时,硅丙乳液及其胶膜的稳定性、耐水性和力学性能俱佳。     

制备工艺对硅/丙复合乳液稳定性的影响

采用乳液聚合方法制备含氢聚硅氧烷（ＰＨＭＳ）／丙烯酸丁酯（ＢＡ）复合乳液。讨论了不同乳化剂及聚合方法对乳液稳定性的影响。结果表明：采用非离子型乳化剂聚乙二醇辛基苯基醚及半连续滴加法可制得稳定的ＰＨＭＳ／ＢＡ复合乳液。     

丙烯酸酯乳液聚合研究进展

综述了近几年来丙烯酯乳液聚合方法新进展,包括反应性乳化剂存在下的乳液聚合、超浓乳液聚合、Reversible addition fragmentation chain transfer(RAFT)种子乳液聚合、辐射及氧化还原引发的乳液聚合等。另外,对不同丙烯酸酯乳液体系的动力学研究也做了详细阐述。     

氟碳铝型材保护膜用压敏胶的制备与性能

以丙烯酸丁酯(BA)和丙烯酸异辛酯(2-EHA)为软单体、甲基丙烯酸甲酯(MMA)为硬单体、丙烯酸(AA)和丙烯酸羟丙酯(HPA)为功能单体,采用降低PSA(压敏胶)的Tg(玻璃化转变温度)和预乳化半连续乳液聚合法合成了丙烯酸酯PSA乳液。研究结果表明:当m(软单体)∶m(硬单体)∶m(功能单体)=90∶5∶5、m(BA)∶m(2-EHA)=1∶2、w(AA)=1.0%、w(HPA)=5%、w(缓冲剂)=0.25%、w(引发剂)=w(复合乳化剂)=0.6%且m(阴离子型乳化剂)∶m(非离子型乳化剂)=1∶1时,PSA乳液的综合性能相对最好,用该PSA制成的保护膜对氟碳铝型材具有良好的附着力,并且其耐湿热老化性能和耐热老化性能俱佳。     

核壳型醋丙乳液胶黏剂的制备及其性能研究

乳胶粒子形态控制是聚合物乳液研究的重要领域,几十年中在聚合物材料、涂料、胶黏剂等诸多领域的成功的应用使得核壳结构聚合物复合粒子备受关注。采用种子乳液聚合法,采用复配乳化剂体系合成了以醋酸乙烯酯为核,醋酸乙烯酯和丙烯酸丁酯为壳的乳液,并重点研究了单体滴加速率、SDS与OP-10质量比、引发剂用量对乳液性能的影响,通过透射电镜和红外光谱仪表征了乳胶粒子核壳结构的存在。