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种子聚合工艺合成新型羧基丁苯胶乳及其应用研究
Preparation and Application of Carboxylated Styrene-butadiene Latex Seed Block Copoly of Uniform
【作者】 王德智;
【导师】 谢益民;
【作者基本信息】 山东轻工业学院 , 轻工技术与工程, 2010, 硕士
【摘要】 随着科学技术不断发展和人民生活水平的提高,高档涂布纸(铜版纸、板纸)需求量越来越大,致使涂层用丁苯胶乳需求量不断增长,推动了羧基丁苯胶乳的快速发展,研究和开发新型羧基丁苯胶乳具有广泛的理论和社会意义。本文详细探讨了羧基丁苯胶乳的合成手段,阐述了乳液聚合技术的工艺特点,剖析了乳液聚合机理,研究了以种子聚合工艺合成羧基丁苯胶乳的合成方法,研究了丁苯胶乳链段中接入不同的功能单体基团对丁苯胶乳理化指标以及应用性能的影响,运用种子乳液聚合的优点合成了广泛应用性能的羧基丁苯胶乳。以苯乙烯和丁二烯为主要单体原料,以水为连续相,以过硫酸盐为引发剂,选用十二烷基硫酸钠SDS与Tween-60作为复合乳化剂,在一定反应时间、反应温度和转速条件下合成稳定的羧基丁苯胶乳。根据不同的用户需要,可以接入不同种类和不同数量的基团,满足不同的市场需求。系统地探讨了乳化剂用量与种类、引发剂用量和种类、聚合温度、反应时间、搅拌速率、单体配比、功能单体加入量等因素对羧基丁苯胶乳产品固含量、粘度、稳定性、应用性能以及乳液的粒径大小、粒子分布的影响。通过大量的试验确定最佳合成条件为:乳化剂用量1.5-3%,引发剂用量1-3%,聚合温度80-90℃,反应时间8 h,搅拌速率200-260 rpm,苯乙烯与丁二烯单体配比在60/40-45/55,各物料量是相对于苯乙烯和丁二烯而言的。通过利用胶乳的种子设计理论,可以有效的控制最终产品的粒子大小与粒子分布,可以使用不同的生产工艺,选择不同的种子来得到不同的粒子的产品,满足不同的需要。较小的粒径和分布窄的产品,配制出来的涂料有很好的黏结强度和很好了流变性能,可以满足高速涂布纸机的使用要求。用较大粒径的产品涂布生产的纸有透气度很好的特点。通过大量实验作了应用性能的比较,由于很多因素是相辅相成的,所以要根据客户的不同需求来改变丁苯胶乳的配方,合成不同用途的丁苯胶乳,满足客户的不同要求。
【Abstract】 With the development of the technology and people’s life, the requirement of slap-up coated paper is much larger, which drives the fast development of the carboxylated styrene-butadiene latex. So studying on the synthesis of new-style carboxylated styrene-butadiene latex is of a great significance both in theoretical and in social side.The synthesis methods of carboxylated styrene-butadiene latex were discussed in this research, and the technical characters of emulsion polymerization were given. What’s more, the mechanism of emulsion polymerization was interpreted and the synthesis method of carboxylated styrene-butadiene latex via seeded polymerization was studied. The effect on the physical-chemical quality and application of the styrene-butadiene latex was studied by connecting the different functional monomers to carboxylated styrene-butadiene latex segment was discussed. Carboxylated styrene-butadiene latex was synthesized by core/shell emulsion polymerization.The styrene (St) and the butadiene (Bd) were as the main raw materials, the water was as the continuous phase, the ox-reductant and azo-compounds were as the complex initiators and the SDS and Tween-60 were as composite emusifier, the carboxylated styrene-butadiene latex was prepared at a certain time, temperature and rotate speed. The different kind and different quantity segment can be connected to the carboxylated styrene-butadiene latex, depending different demand and different market.The effects of varying factors of the concentration of emulsifier, the concentration of initiator, reaction temperature, the stirring speed, the molar ratio of ST/SB and the concentration of functional monomers on the content of solid, the viscosity, particle size, particle morphology of carboxylated styrene-butadiene latex were investigated respectively. What’s more, the optimum conditions of the synthesis were determined as follows:the dosage of emulsifier was 1.5-3%, the concentration of initiator was 1-3%, the initiation temperature was 80-90℃, the reaction time was 8h, the stirring speed was 200-260 rpm and the molar ratio of St/Bd was 60/40-45/55.The size and the distribution of the particle can be effectively controlled via the designing theory of latex seed. Using the different synthesis technology, the product can be attained by the different seed, which can meet the different demand. What’s more, the dope has well felting intensity and good rheological properties by using the small grain size and narrow distribution product. The paper has well permeability, which was coated by the bigger seed product.The application performance of the styrene-butadiene latex was compared via lots of experiment. Because of a great many of factors supplement each other, so the formula of the styrene-butadiene latex can be changed by the different demand. And the styrene-butadiene latex with different use can be synthesized, which for the client’s different demand.