基于RAFT聚合制备梳型分散剂及其性能研究

Preparation and Performance of Comb-Like Dispersants via RAFT Polymerization

活性聚合具有结构可设计性强、产品分子量分布窄的特点,采用RAFT技术,苯乙烯、马来酸酐、异戊烯基聚氧乙烯醚(Mn=2300)和链转移剂3-(苄硫基硫代羰基硫基)丙酸质量比为19:19:0.76:1,RAFT试剂与AIBN摩尔比5:1,温度80℃,在丁酮中溶液聚合制备了梳型分散剂。聚合过程中ln([M]o/[M])与反应时间,以及聚合物数均分子量与反应转化率均呈一级线性关系,聚合过程具有活性聚合特征。M_n=1.03×10~4,PDI=1.14,XPS与FTIR等分析结果表明分散剂单分子层多点物理吸附于颗粒表面,吸附层厚度1.33 nm。制备的48%吡虫啉水悬浮剂在pH=7.0~8.0时,zeta电位绝对值最大,TURBISCAN测试稳定性参数TSI相对传统分散剂小,较稳定。

Polymers prepared via active polymerization have properties of well-designed molecular structure and narrow molecular weight distribution.A“comb-like”polymer dispersant was prepared via reversible addition-fragmentation chain transfer(RAFT)polymerization in this study.The reaction conditions were:mass ratio of styrene,maleic anhydride,isopentene polyoxyethylene ether(Mn=2300)and RAFT reagent BCTPA=19:19:0.76:1,molar ratio of RAFT reagent and AIBN=5:1,and reaction temperature=80℃in butanone.The relationship between ln([M]o/[M])and reaction time,and number-average molecular of product and polymerization conversion are both under first order kinetics,which indicates that the polymerization process follows active polymerization.The produced polymer has Mn=1.03×104and PDI=1.14,and FTIR and XPS results show that the adsorption behavior of the dispersant on imidacloprid is under monolayer multi-position physical interaction.The thickness of the adsorbent layer is1.33nm.The highest zeta potential of48%imidacloprid SC is found at pH=7.0~8.0.The TSI results from TURBISCAN shows that the SC prepared from polymer is more stable than that of traditional dispersants.