有机硅基RAFT试剂制备聚醚改性有机硅消泡剂

Preparation of polyether modified organosilicon defoamer by organosilicon-based RAFT reagent

以八甲基环四硅氧烷和巯丙基甲基二甲氧基硅烷为原料,合成了巯基硅油;再以巯基硅油、CS_(2)和2-溴代异丁酸甲酯为原料,合成了有机硅基可逆加成-断裂链转移(RAFT)试剂(RAFT-SSO);RAFT-SSO与甲基封端的烯丙基聚氧乙烯醚(EO)、甲基封端的烯丙基聚氧丙烯醚(PO)采用RAFT聚合反应合成了聚醚改性有机硅消泡剂(RS-EOPO)。采用FTIR、^(1)HNMR,GPC对RS-EOPO进行了结构表征,对其消泡、抑泡、相容性进行了测试,并将RS-EOPO与进口消泡剂性能进行对比。RS-EOPO最佳合成工艺条件为RAFT-SSO相对分子质量为2000、m(EO)∶m(PO)=1∶4、m(RAFT-SSO)∶m〔醚(EO和PO)〕=1∶1.15、反应温度75℃、反应时间8 h、引发剂用量为EO(3.45 g)和PO总质量的2%。在上述条件下,RS-EOPO收率为91.8%。

Thiol silicone oil,prepared from octamethylcyclotetrasiloxane and mercaptopropyl methyl dimethoxy silane,was reacted with CS_(2),and 2-bromoisobutyrate methyl to synthesize organosilicon-based reversible addition-fragmentation chain transfer(RAFT)reagent(RAFT-SSO).And polyether modified organosilicon defoamer(RS-EOPO)was finally obtained from RAFT polymerization of RAFT-SSO with methyl terminated allyl polyoxyethylene ether(EO)and methyl terminated allyl polyoxypropylene ether(PO).RS-EOPO was characterized by FTIR,^(1)HNMR and GPC for structural analysis,and further evaluated for its performance on defoaming,antifoaming and compatibility in comparison to imported defoamer.The optimal synthesis conditions of RS-EOPO were obtained as follows:relative molecular mass of RAFT-SSO 2000,m(EO)∶m(PO)=1∶4,m(RAFT-SSO)∶m[ether(EO and PO)]=1∶1.15,reaction temperature 75℃,reaction time 8 h,initiator amount being 2%of the total mass of EO(3.45 g)and PO.Under the above reaction conditions,the yield of RS-EOPO reached 91.8%.