原位聚合法制备纳米TiO2／硅丙复合乳液

北京化工大学材料科学与工程学院的徐瑞芬等采用硅丙偶联剂对纳米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／硅丙复合乳液。采用透射电子显微镜表征了乳液的结构及其形态。     

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。     

核壳结构纳米TiO2／PMMA／PU复合基耐洗刷涂料制备

为制备水性聚氨酯（WPU）耐洗刷涂料,用硅烷偶联剂改性纳米TiO2,并采用预聚体分散、种子原位乳液聚合法分别制备了TiO2／PU、TiO2／聚甲基丙烯酸甲酯（PMMA）／PU复合乳液。探讨了n（-NCO）：n（-OH）（R值）、纳米TiO2加入方式与含量、MMA／PU质量比及填料与功能助剂类型对PU耐洗刷性能的影响。透射电镜形貌观察表明：TiO2／PMMA／PU复合乳液乳胶粒子具有以TiO2为核的核壳结构。结果表明乳液种类对涂膜耐洗刷性影响较大,当纳米TiO2含量为0．5％、PMMA／PU质量比1：4时,多层核壳结构复合乳液的耐洗刷性最好,达6350次;选择片状结构、质地较硬的填料、微纤及防水助剂能显著提高PU涂料耐洗刷性,优化配方可制备出耐洗刷性达10000次以上PU乳液涂料。     

纳米TiO2/PSB复合乳液的制备与性能研究

为了提高丁苯乳液涂膜力学性能,用硅烷偶联剂(KH-570)改性纳米TiO2,采用半连续种子乳液聚合法,制备TiO2/聚丁苯(PSB)复合乳液。采用FT-IR、TEM表征TiO2/PSB复合乳液乳胶粒子结构,结果表明合成了以TiO2为核的核壳结构纳米TiO2/PSB乳胶粒子。探讨了纳米TiO2、乳化剂、电解质、引发剂及增稠剂用量、聚合时间与温度、单体配比等对TiO2/PSB复合乳液性能的影响。确立了适宜的聚合工艺条件:纳米TiO2、乳化剂用量分别为总质量的0.5%和3.5%,电解质和引发剂用量为单体质量的0.4%,聚合温度和时间分别为64℃和3.5 h,可制备出高固高黏且性能优良的复合乳液。经纳米TiO2改性的PSB复合乳液涂膜性能较未改性的,在黏度、硬度、耐冲击性、耐洗刷性、附着力及耐水性等方面均有明显改善。     

纳米TiO2原位聚合硅丙复合乳液的制备

采用硅烷偶联剂对纳米二氧化钛进行表面处理,以改性纳米二氧化钛和有机硅中间体为种子乳液,以过硫酸钾为引发剂,甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(MBA)为主要共聚单体,通过原位聚合反应,合成纳米TiO2-硅丙复合乳液。采用红外光谱、透射电镜(TEM)、激光粒度分布等手段,对所制备的纳米TiO2-硅丙复合乳液进行了表征,证明所得产品是硅氧烷和丙烯酸酯的共聚物,具有核/壳结构,且乳液粒径分布较窄,平均粒径在63 nm左右。     

核/壳乳液聚合中影响乳胶粒形态的因素

控制乳液的乳胶粒形态对乳液的许多实际应用有重要的意义，本文简要介绍了核／壳结构聚合物乳液的制备，并重点讨论了核／壳结构聚合物乳液聚合过程中各种因素对核／壳结构聚合物乳液乳胶粒子形态的影响。     

纳米TiO2／硅丙复合乳液的光催化抗菌性能研究

采用原位聚合法制备纳米TiO2／硅丙复合乳液。由透射电子显微镜观察到纳米TiO2／硅丙复合乳液胶膜中纳米颗粒呈单分散状态，达到了纳米尺寸。通过分光光度分析方法，测得该膜在200—400nm紫外光光波范围吸收强度大于2．0，在可见光光波范围有明显的光吸收。杀菌实验测试结果为：该乳液对枯草杆菌黑色变种芽孢、大肠杆菌和金黄色葡萄球菌的杀灭率达到98％以上；该乳液胶膜对乙肝表面抗原(HbsAg)作用8h以后，HbsAg由阳性转变为阴性。研究表明，纳米TiO2／硅丙复合乳液及其乳液胶膜具有显著的光催化效应，能将其吸收的光能转化为杀菌，抗病毒的化学能。     

苯乙烯无皂乳液聚合接枝纳米TiO2的研究

采用无皂乳液聚合法，使苯乙烯单体（St）在烷基化预处理的纳米TiO2粒子的表面进行接枝聚合，得到了稳定的以纳米TiO2粒子为核、接枝聚苯乙烯为壳的复合颗粒（TiO2-g-PS）。研究了烷基化预处理以及聚合条件（单体浓度、引发剂浓度、反应时间）对TiO2表面接枝改性的影响，并对其聚合机理进行了探讨。结果表明：PS以化学键成功地接到纳米TiO2的表面，并且可以通过改变接枝聚合的条件来调节粒子上所接聚苯乙烯的结构，为进一步优化纳米粒子填充聚合物复合材料的结构和性能之间的关系建立基础。     

核壳结构纳米TiO2/PMMA/PU复合基耐洗刷涂料的制备

为制备水性聚氨酯(WPU)耐洗刷涂料,用硅烷偶联剂改性纳米TiO2,并采用预聚体分散、种子原位乳液聚合法分别制备了TiO2/PU、TiO2/聚甲基丙烯酸甲酯(PMMA)/PU复合乳液.探讨了n(-NCO):n(-OH)(R值)、纳米TiO2加入方式与含量、MMA/PU质量比及填料与功能助剂类型对Pu耐洗刷性能的影响.透射电镜形貌观察表明:TiO2/PMMA/PU复合乳液乳胶粒子具有以TiO2为核的核壳结构.结果表明乳液种类对涂膜耐洗刷性影响较大,当纳米TiO2含量为0.5%、PMMA/PU质量比1:4时,多层核壳结构复合乳液的耐洗刷性最好,达6 350次;选择片状结构、质地较硬的填料、微纤及防水助剂能显著提高PU涂料耐洗刷性,优化配方可制备出耐洗刷性达10 000次以上PU乳液涂料.     

醋酸乙烯的种子核／壳乳液聚合研究

用聚氯乙烯种子为核进行了VAc的核／壳乳液聚合，测试了乳胶粒子的平均直径和聚合物的玻璃化温度，发现该PVC／PVAc核壳聚合乳胶粒子有不同于均聚合物的两相结构，测试了乳液的应用性能。     

自交联型有机硅氧烷改性丙烯酸乳液的合成

通过核壳乳液聚合法制各自交联型有机硅氧烷改性丙烯酸乳液,探讨了乙烯基有机硅氧烷的种类、用量和添加方式,乳化剂,聚合反应的引发体系和pH值等对乳液涂膜性能的影响规律。研究结果表明,采用含水解阻碍性官能团的乙烯基三异丙氧基硅氧烷能提高自交联硅丙乳液的稳定性,增加乳液中有机硅氧烷的含量达10％以上,从而可大大提高涂膜性能。此外,当采用60／40—80／20的添加方式添加乙烯基有机硅氧烷、反应型乳化剂、前期过氧化物引发和后期氧化还原引发的混合引发体系,以及保持体系的pH值在4.5～7的范围内时,能降低聚合过程中有机硅氧烷的水解和缩合反应程度,提高乳液涂膜的交联密度以及耐水耐溶剂等性能,制各出涂膜综合性能优异的自交联型硅丙乳液。     

Preparation of toughened PMMA through PEG-modified urethane acrylate/PMMA core–shell composite particles

Poly(urethane acrylate) (PUA)/poly(methylmethacrylate) (PMMA) core–shell composite particles were prepared by two-stage emulsion polymerization. The sizes of composite particles could be varied from 25 to 210 nm by introducing polyoxyethylene (POE) groups to the urethane acrylate molecular backbone. Core–shell morphology was identified by investigating the polarity of the surface of the core and shell polymer particles and by measuring the contact angle of the composite particles. A composite particle prepared with relatively small particles (about 20 nm) did not show the core/shell morphology, because the high polar surface of the core polymer particle and the low-stage ratio of the core to the shell cause the formation of a core/shell two-stage latex to be more thermodynamically unstable. The fracture toughness of rubber-toughened PMMA containing PUA/PMMA composite particles increased as the particle sizes decreased and the shell thickness of the composite particles increased. In particular, when the average size of the composite particle was about 43 nm and the stage ratio was 50/50, the fracture toughness of the rubber-toughened PMMA increased more than three times compared with that of pure PMMA. Furthermore, the transparency of toughened PMMA could be maintained up to 91% in the visible spectra range. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2291–2302, 1998     

核壳结构纳米TiO_2/丁苯复合乳液制备研究

为制备高固高粘新型丁苯乳液(SBRL),以经硅烷偶联剂改性的纳米TiO2为核,阴离子乳化剂十二烷基硫酸钠(SDS)与非离子乳化剂辛基苯基聚氧乙烯醚(OP-10)为复合乳化剂,其质量比为1:1,采用半连续种子乳液聚合法,制备了具有核壳结构的纳米TiO2/聚丁苯(PSB)复合乳液,并测定了复合乳液的性能。确定了适宜聚合工艺条件:纳米TiO2为总量0.5%,乳化剂用量为3.5%,引发剂用量为单体量0.4%,聚合温度为64℃,可以制备出性能良好的复合乳液。所制乳液固含量最高可达50%以上,粘度可依据不同使用要求调节。     

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。     

Preparation and properties of core–shell nanosilica/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) latex

A core–shell nanosilica (nano‐SiO₂)/fluorinated acrylic copolymer latex, where nano‐SiO₂ served as the core and a copolymer of butyl acrylate, methyl methacrylate, and 2,2,2‐trifluoroethyl methacrylate (TFEMA) served as the shell, was synthesized in this study by seed emulsion polymerization. The compatibility between the core and shell was enhanced by the introduction of vinyl trimethoxysilane on the surface of nano‐SiO₂. The morphology and particle size of the nano‐SiO₂/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) [P(MMA–BA–TFEMA)] core–shell latex were characterized by transmission electron microscopy. The properties and surface energy of films formed by the nano‐SiO₂/P(MMA–BA–TFEMA) latex were analyzed by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, and static contact angle measurement. The analyzed results indicate that the nano‐SiO₂/P(MMA–BA–TFEMA) latex presented uniform spherical core–shell particles about 45 nm in diameter. Favorable characteristics in the latex film and the lowest surface energy were obtained with 30 wt % TFEMA; this was due to the optimal migration of fluorine to the surface during film formation. The mechanical properties of the films were significantly improved by 1.0–1.5 wt % modified nano‐SiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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。     

Nano‐SiO2/PMMA‐PU composite particles with core‐shell structure via emulsion polymerization and their application in epoxy resin

A novel method of nano‐SiO₂/poly(methyl methacrylate)(PMMA)‐polyurethane(PU) composite particles modifying epoxy resin is reported. The composite particles with the obvious core‐shell structure were prepared by emulsion polymerization of PMMA and PU prepolymer on the surface of nano‐SiO₂. The diameter of the composite particles was 50–100 nm with dark core SiO₂ (30–60 nm) and light shell polymer of PMMA and PU (20–30 nm); moreover, PU was well distributed in PMMA with about 10 nm diameter. After nano‐SiO₂ was encapsulated by PMMA and PU, the Si content on the surface decreased rapidly to 2.08% and the N content introduced by PU was about 1.27%. The ratio of polymer to original nano‐SiO₂ (f_p), the grafting ratio of polymer to original nano‐SiO₂ (f_r) and the efficiency grafting ratio of polymer (f_e) were, respectively, about 116.7%, 104.4%, and 89.5%. The as‐prepared composite particles were an effective toughness agent to modify epoxy resin, and the impact strength of the modified epoxy resin increased to 46.64 kJ m^?2 from 19.12 kJ m^?2 of the neat epoxy resin. This research may enrich the field of inorganic nanoparticles with important advances toward the modification for polymer composite materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41919.