聚丙烯酸酯/纳米二氧化硅复合乳液的制备

将甲基丙烯酸羟乙酯与硅酸四乙酯经酯交换制得的二甲基丙烯酰氧基硅酸二乙酯与丙烯酸酯进行乳液聚合，制得了不同二氧化硅含量的稳定聚丙烯酸酯/纳米二氧化硅复合乳液；讨论他乳化剂种类和用量，以及不饱和硅酸酯单体用量对聚合转化率及乳液稳定性的影响。用红外光谱和透射电镜表征了乳胶膜。试验结果表明，采用乳液聚合可以制得原位水解并稳定分散的聚丙烯酸酯/纳米二氧化硅复合乳液。     

聚丙烯酸酯/纳米二氧化硅复合乳液的制备及其在防水涂料中的应用

利用乳液聚合制备原位分散的聚丙烯酸酯/二氧化硅纳米复合材料,采用红外、透射电镜对试样进行了分析。采用该乳液制备的纳米二氧化硅改性聚丙烯酸酯防水涂料具有优良的耐洗刷性能。     

Pickering乳液聚合法制备聚丙烯酸酯/纳米SiO_2复合乳液及其在涂料中的潜在应用

以六甲基二硅胺烷(HMDS)改性的纳米二氧化硅(SiO_2)为稳定剂制备了稳定性良好的Pickering乳液,再通过乳液聚合法制备了聚丙烯酸酯/纳米SiO_2复合乳液。通过单体转化率、粒径、成膜性等指标对乳液稳定聚合的条件进行了优化。采用傅里叶变换红外光谱仪、热重分析仪、扫描电镜、透射电镜和最低成膜温度测试仪对SiO_2粒子、乳液和乳胶膜进行了表征。该复合乳液粒径较小,稳定性良好,最低成膜温度为32°C,以其制备的胶膜附着力达到1级,铅笔硬度可达3H,耐水性良好。     

SiO2溶胶在微滴乳液聚合中的原位纳米复合

本文提出将正硅酸乙酯(TEOS)的非水sol-gel反应与单体的微滴乳液聚合技术相结合,制备聚丙烯酸酯/二氧化硅纳米复合乳液。首先采用凝胶时间的测定与动态光散射等手段研究TEOS在甲酸催化下的非水sol-gel反应动力学,表明当甲酸/TEOS的摩尔比大于6,有利于形成颗粒状纳米二氧化硅溶胶。以硅烷偶联剂KH-570对非水溶胶原位改性,然后引入丙烯酸酯共聚单体中,研究硅溶胶的存在对单体微滴乳液聚合的影响。结果表明,聚合动力学与单体的微滴乳液聚合基本相似,但二氧化硅的引入改变了单体微滴的均一性和剪切分散的稳定性,导致乳胶粒径逐渐增大,粒径分布变宽。复合乳胶粒是若干无机粒子以微相区被包覆于有机聚合物中的纳米复合结构形态。     

纳米SiO_2/聚丙烯酸酯复合防锈乳液的合成研究

采用原位无皂乳液聚合法,以改性纳米二氧化硅粒子为反应活性中心,取代传统乳液聚合中的乳化剂,以磷酸酯为功能单体合成了纳米二氧化硅/聚丙烯酸酯复合防锈乳液。结果表明:所制备的乳液反应体系稳定,乳液粒径约为100 nm,当纳米二氧化硅用量为主单体质量的4%~6%,磷酸酯功能单体用量为主单体质量的2%~4%时,乳液综合性能最佳。以该乳液为基料制备的水性防锈涂料防锈性能优异,经240 h耐盐雾试验测试,钢板表面无泡无锈蚀产生。     

聚丙烯酸酯/纳米二氧化硅Pickering复合乳液的制备及性能

以改性纳米SiO_2粉体作为稳定剂稳定丙烯酸酯类单体,采用Pickering乳液聚合法制备聚丙烯酸酯/纳米SiO_2复合乳液。以单体转化率和乳液凝胶率为指标,对乳液聚合条件进行了优化,通过光学显微镜观察了乳状液的形貌,用动态激光散射(DLS)和透射电镜(TEM)、傅里叶红外光谱仪(FTIR)和扫描电镜(SEM)对乳液及其成膜进行了表征。结果表明,SiO_2与乙烯基三乙氧基硅烷(A-151)的质量比为5∶1、甲基丙烯酸甲酯与丙烯酸丁酯的质量比为1∶4时,乳液性能最优。DLS和TEM结果表明,复合乳液的粒径在790 nm左右;FTIR结果表明,复合乳液中有纳米SiO_2的存在;SEM结果表明,纳米SiO_2分散在复合乳液成膜中。将复合乳液应用于皮革涂饰中,应用结果表明,与聚丙烯酸酯乳液涂饰革样相比,Pickering乳液聚合法制备的复合乳液涂饰后革样的透气性、透水气性及耐干湿擦性能都有所提升。     

聚醋酸乙烯酯/纳米SiO_2复合乳液的制备与性能

采用原位乳液聚合法制备了聚醋酸乙烯酯／纳米二氧化硅复合乳液。考察了纳米二氧化硅在聚醋 酸乙烯酯乳液内及乳胶膜中的分散性:纳米二氧化硅用量对复合乳液性能的影响。结果表明:与普通乳液相 比,复合乳液的干态粘接强度和耐水性明显提高。     

新型复合材料-纳米TiO2/聚丙烯酸酯复合乳液的研究

实验以乳液聚合法制备了纳米TiO2／聚丙烯酸酯复合乳液,发现将未经任何改性处理的纳米TiO2与单体共同发生聚合发应,当添加量在一定范围之内时,可以得到稳定的无机一有机纳米复合乳液,且涂膜性能优良。     

聚丙烯酸酯-硅氧烷/纳米蒙脱土复合乳液的制备

采用种子乳液聚合方法,制备了聚丙烯酸酯-硅氧烷/纳米蒙脱土复合乳液,对复合膜的性能进行了表征。结果表明,复合乳液粒径分布比较均匀,平均粒径随着纳米蒙脱土含量的增加逐渐增大;聚合物与蒙脱土的相界面之间发生键合作用,形成了均相聚合物;当纳米蒙脱土质量分数3%时,复合膜的最大拉伸强度和断裂伸长率分别为6.83 MPa和615.3%。添加纳米蒙脱土后,提高了聚丙烯酸酯-硅氧烷共聚物的热稳定性。     

硅溶胶/聚丙烯酸酯复合乳液的结构和性能研究

采用普通乳液聚合的方法,制备了硅溶胶/聚丙烯酸酯复合乳液.通过透射电镜(TEM)、傅里叶红外光谱仪(FT-IR)和动态激光散射仪(DLS)等对复合乳液中乳胶粒子的结构进行表征,并对复合乳液的涂膜性能进行研究.结果表明,所制备的复合乳液粒子具有核-壳结构,其中核是纳米级的SiO2粒子,壳是聚丙烯酸酯.性能测试结果表明,核-壳结构的存在使得复合乳液的涂膜在硬度、附着力和化学稳定性等方面均优于纯丙乳液及硅溶胶/聚丙烯酸酯的共混乳液.     

二氧化硅形态对有机-无机复合弹性乳液涂膜性能的影响

采用预乳化、半连续种子乳液聚合法为聚合工艺,利用无机二氧化硅改性纯丙烯酸酯弹性乳液,使之兼有有机相和无机相的优点,制备有机-无机复合弹性乳液。分别选用3种不同形态的二氧化硅(纳米二氧化硅粉体、硅溶胶、正硅酸乙酯和A-151)进行对比试验,考察了二氧化硅形态对聚合物膜力学性能、吸水率、光学性能、耐热性等性能的影响。结果表明:二氧化硅形态对有机-无机复合弹性乳液涂膜性能有较大影响,二氧化硅以正硅酸乙酯和A-151的加入方式为最佳。     

乳液法合成纳米SiO_2/聚丙烯酸酯复合材料及其性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和由四甲氧基硅烷(TMOS)制备的硅溶胶为原料,通过乳液聚合制备了纳米SiO2/聚丙烯酸酯乳液,然后通过溶剂挥发法制得复合材料膜。通过红外光谱(FTIR)、透射电子显微镜(TEM)、力学性能测试和热分析(TG)等手段,对乳液形貌、复合膜材料的组成、力学性能、疏水性能和热性能等方面进行研究。结果表明:纳米SiO2同时起到的增塑和增强作用,对复合物成型后的机械性能和吸水性能有复杂的影响;随着纳米SiO2的加入,复合材料的热稳定性增加。     

Study on ultrasonic induced encapsulating emulsion polymerization in the presence of nanoparticles

In this paper, the ultrasonic induced encapsulating emulsion polymerization technique was used to prepare polymer/inorganic nanoparticle composites. The main affecting factors in ultrasonic induced encapsulating emulsion polymerization were studied systematically. The experimental results suggested that the pH value, the type of monomers, the type, content, and surface properties of nanoparticles, the type and concentration of surfactant have great influence on the ultrasonic induced encapsulating emulsion polymerization and the obtained latex stability. If selecting cationic emulsifier (such as cetyl trimethylammonium bromide), low water soluble monomer (such as n‐butyl acrylate and styrene), and hydrophobic nano silica, the inorganic nanoparticles could be encapsulated by polymers through ultrasonic irradiation successfully under alkalescent condition, forming a novel polymer/inorganic nanoparticles composite. The mechanism of ultrasonic induced encapsulating emulsion polymerization and the composite latex stabilization are proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1130–1139, 2001     

明胶代用物AN—BA共聚物的合成和应用

用乳液聚合法合成的丙烯酸丁酯-丙烯腈共聚物是一种性能优良的明胶代用物,而采用无机—有机复合乳液聚合技术合成的含硅的丙烯腈-丙烯酸丁酯共聚物乳液,作为明胶代用物,不仅保留原共聚物的性能,又有良好的渗透性,可改善胶片的照相性能,适用于高温快显机器加工的照片。     

硅酸四乙酯存在下的丙烯酸酯无皂乳液聚合

在含烯丙基的特种醇醚硫酸盐和丙烯基乙醚磺酸钠盐反应型乳化剂存在下,将硅酸四乙酯与丙烯酸酯及偶联剂-甲基丙烯酰氧丙基三甲氧基硅烷进行无皂乳液聚合,有效地防止了原位生成的纳米二氧化硅粒子团聚,同时将其引入丙烯酸酯聚合物侧链形成潜在交联点,协同提高丙烯酸酯共聚物的耐水性和硬度。考察了硅酸四乙酯和硅烷偶联剂用量对无皂乳液聚合行为及乳液性能的影响规律。用该法制得的乳液比起常规方法,具有粒径小、均一度高、无小分子乳化剂杂质,且涂膜硬度高、膜透明度好、耐水性大幅度提高等优点。     

交联型丙烯酸酯核壳纳米复合涂料的制备

详细研究了核壳乳液的聚合机理、聚合工艺和软硬单体的比例、单体的滴加速度、交联单体甲基丙烯酸等对乳液性能的影响.在MMA/BA/DMMA/MAA聚合体系中,用半连续法制备出性能优越的核壳乳液,核壳乳液的性能在一定范围内随着交联单体甲基丙烯酸和DMMA的用量的增加提高,甲基丙烯酸最佳用量为单体的4%～6%,DMMA的最佳用量为2.0%.乳液中加入2%纳米二氧化硅对乳液进行改性得到纳米复合涂料.加入的纳米SiO2分散好,不产生团聚,并能显著改善复合涂料的力学性能和耐水性.     

改性二氧化硅-丙烯酸酯杂化细乳液的制备和性能研究

通过细乳液聚合方法制备了改性二氧化硅／丙烯酸酯杂化高分子乳液。考察了偶联剂改性前后对杂化乳液粒径的影响。杂化乳液成膜后通过XPS测定发现，未见Si激发，说明二氧化硅被丙烯酸酯包裹。在SEM照片上可以发现改性后的二氧化硅与丙烯酸酯亲和力增加，改性后的杂化乳液高分子比未改性的杂化乳液高分子的韧性有了一定的提高。     

Nanosilica filled poly(glycerol‐sebacate‐citrate) elastomers with improved mechanical properties,adjustable degradability,and better biocompatibility

Modified nano‐fumed silica (mn‐silica)/poly(glycerol‐sebacate‐citrate), in which mn‐silica loadings varied from 0 to 20 phr, were prepared by in situ polymerization and surface modification. The influence of mn‐silica loadings on the structure and properties of the composites was studied. Scanning electron microscope (SEM) and transmission electron microscope (TEM) photos showed that the mn‐silica dispersed well as nano‐scale network in the matrix, and exhibited good interfacial bonding with the matrix. The mn‐silica filled composites exhibited excellent comprehensive properties relative to the unfilled elastomers. Specially, the tensile strength improved from 0.9 MPa to 5.3 MPa. Results of the in vitro degradation test suggested that mn‐silica loading could adjust the degradation rate of the composites in simulated body fluid solution. The MTT colorimetry with L929 cells substantiated that the introduction of mn‐silica weakened the cytotoxicity of elastomers and made the composites accepted as qualified biomedical materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of mesoporous SBA-15 contents on the properties of polystyrene composites via in-situ emulsion polymerization

Different loading of mesoporous molecular sieve SBA-15 was used to prepare polystyrene (PS)/SBA-15 composite materials via in-situ emulsion polymerization. The influence of SBA-15 silica on the styrene emulsion polymerization was studied regarding to the monomer conversion, particle size and particle size distribution, stability and viscosity of the resulting emulsion. The structure and properties of the composites were investigated by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and gel permeation chromatography (GPC). In addition, the glass transition temperature (T_g), thermal mechanical property and thermal stability of the composite film were measured by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. The results indicated that the composite emulsion showed high monomer conversion, thick viscosity, low coagulum, uniform particle size and broad size distribution. Molecular weight of the polymer decreased with the increase of mesoporous silica. SBA-15 silica was dispersed evenly in PS matrix at a loading of 5 %. The PS/SBA-15 composite material containing 10 % silica maintained a certain ordered structure. DMA results demonstrated that PS/SBA-15 composite exhibited greater storage modulus and high T_g compared to pure PS. The improved thermal stability and T_g of the composite were also confirmed by the TGA and DSC.     

Preparation and properties of nano diamond/6F‐bisphenol A‐based cyanate ester composites

The aim of this study was to improve thermal conductivity, thermal stability, and mechanical properties of bisphenol A dicyanate ester (BADCy) by adding bisphenol A dicyanate ester containing fluorine (F‐BADCy) and nano diamond. The cyanate esters containing fluorine/nano diamond composites having various ratios of BADCy, F‐BADCy, and nano diamond were prepared. Thermal stability and thermal conductivity of the samples were evaluated by thermogravimetric analysis, differential scanning calorimetry and laser flash method, respectively. The samples were characterized with the following analysis; gel content, water absorption capacity, and stress‐strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy (SEM). The obtained results prove that the cyanate ester containing fluorine/nano diamond composites have good thermal and mechanical properties and they can be used in many applications such as electronic devices, materials engineering, and other emergent. POLYM. COMPOS., 34:1977–1985, 2013. © 2013 Society of Plastics Engineers