含巯基有机硅改性水性苯丙乳液的制备及性能

Preparation and performance of waterborne styrene-acrylic emulsion modified with mercaptan silicone

以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、苯乙烯(St)和丙烯酸(AA)为反应单体,利用羟基硅油(SO)与3-巯丙基甲基二甲氧基硅烷(MPDMS)制备的含巯基有机硅(PMMS)为改性剂,通过种子乳液聚合的方法,制备了一系列有机硅改性水性苯丙复合乳液。通过红外光谱(FTIR)、核磁共振(NMR)和凝胶渗透色谱(GPC)表征PMMS的合成;通过动态光散射(DLS)、热失重分析(TG)和扫描电子显微镜(SEM)等探究了PMMS含量对水性复合乳液的稳定性、乳胶膜的耐水性、热稳定性以及力学性能的影响。结果表明,当PMMS的含量为6%(质量分数,下同)时,改性乳液分散均匀,稳定性较好;其改性乳胶膜的水接触角从改性前的31.1°增至97.8°;吸水率从改性前的6.53%降至2.96%;其拉伸强度为2.69 MPa,较改性前提高了62.9%;失重5%时的分解温度为307.26℃,较未改性前提高了75.79℃。

In this article,mercaptan silicone(PMMS)was firstly synthesized with hydroxyl-group-containing silicone oil and 3-mercaptopropylmethyldimethoxysilane as monomers.Then,a series of mercaptan-silicone-modified styrene-acrylic waterborne composite emulsions were prepared via seed emulsion polymerization with PMMS as a modifier and butyl acrylate,methyl methacrylate,styrene,and acrylic acid as monomers.Infrared spectroscopy,nuclear magnetic,and gel permeation chromatography were performed to characterize the structure and molecular weight of PMMS.The waterborne emulsion stability,water resistance,thermal stability,and mechanical properties of the samples loaded with various amounts of PMMS were further investigated using dynamic light scattering,thermogravimetric analysis and scanning electron microscopy,etc.These results demonstrated that the modified emulsion had good dispersion and excellent stability with the addition of 6%PMMS(quality score).Compared to pure latex film,the contact angle of the modified latex film increased from 31.1°to 97.8°,and the water absorption rate decreased from 6.53%to 2.96%.In addition,the mechanical strength and decomposition temperature at 5%weight loss of the modified latex film increased by62.9%and 75.79°C than pure latex film,respectively.