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 organic silicone based raft reagent

摘要:

以八甲基环四硅氧烷和巯丙基甲基二甲氧基硅烷为原料，合成巯基硅油；再以巯基硅油、二硫化碳和2-溴代异丁酸甲酯为原料，合成有机硅基RAFT试剂；采用可逆加成断裂链转移（RAFT）聚合，让有机硅基RAFT试剂与甲基封端的烯丙基聚醚（EO和PO）反应合成聚醚改性有机硅消泡剂。最佳工艺条件为有机硅基RAFT试剂相对分子量为2000，m(EO)∶m(PO)=1∶4，m(有机硅基RAFT试剂)∶m(醚)=1∶1.15，反应温度75 ℃，反应时间8 h，引发剂用量为甲基封端的烯丙基聚醚质量的2%，收率91.8%。采用FTIR、NMR，GPC对聚醚改性有机硅消泡剂进行结构表征，并将其应用于涂料和乳液中测定消泡抑泡等相关性能。

Abstract:

Synthesis of thiol silicone oil using octamethylcyclotetrasiloxane and mercaptopropyl methyl dimethoxy silane as raw materials; synthesis of organosilicon based RAFT reagents using thiol based silicone oil; The polyether modified silicone defoamer is synthesized by the reaction of silicone based RAFT reagent with methyl terminated allyl group polyethers (EO and PO) through reversible addition breaking chain transfer polymerization. The optimal process conditions were as follows: the equivalent molecular weight of silicone based RAFT reagent was 2000, m (EO)∶ m (PO)=1∶4, m (organosilicon based RAFT reagent): m (ether)=1∶1.15, the reaction temperature was 75 ℃, the reaction time was 8 h, the amount of initiator was 2% of the mass of methyl terminated allyl group polyether, and the yield was 91.8%.The structure of polyether modified silicone defoamer was characterized by FTIR, NMR and GPC, and it was used in coatings and lotion to determine the defoaming and inhibiting properties.