Construction Of Novel Organosilicon Materials By Thiol Oxidative Coupling Reaction

Organosilicon materials have excellent high and low temperature resistance,aging resistance,weather resistance,insulation and biocompatibility,and are widely used in aerospace,medical and health,electronic and electrical,construction,transportation and other industries.Thiol groups as a highly reactive group can be carried out in a variety of reactions.However,the most direct thiol oxidative coupling reaction has not been utilized to prepare organosilicon materials.In this thesis,we will use poly[(mercaptopropyl)methyldimethylsiloxane]and thiol-terminated heterochain polysiloxane as raw materials to prepare new silicone foams and silicone elastomers by thiol oxidative coupling reaction,and study their properties.The main contents includes two aspects as follows.1.Preparation of silicone foams by thiol oxidative coupling reaction.By altering the formulations,including solvent species,the volume of solvent,the amounts of oxidant and catalyst,molecular weight of PMMS,and the-SH content in PMMS,the bubble generation,coalescence,and trapping can be controlled,thereby leading to a tunable foamed structure from closed cells to open cells,as well as a variety of densities(0.13-0.44 g cm-3).These foams showed a good compressive property and low thermal conductivity,suggesting their potential as thermal insulation materials.Moreover,the excellent oleophilic and hydrophobic properties of these foams impart their promise as candidates for efficient absorbents to rapidly absorb various oils with high capacities(7.82-37.29 g g-1),and separate oil/water mixture and oil in water emulsion with high separation efficiencies of>98%and 99.7%.This work may pave new ways for the exploration of silicone foams by selecting thiol-containing polymers and using H2O2 as the oxidant.2.A series of thiol-terminated heterochain polysiloxanes were prepared by thiol-ene click reaction,and then a series of silicone elastomers containing dynamic disulfide bonds were prepared by sulfhydry1-containing compounds as crosslinking agents via thiol oxidative coupling reaction.The tensile test was used to characterize the mechanical properties of the elastomer,and the effects of the type and amount of crosslinking agent on the properties of the elastomer were explored.The results showed that the type of cross-linking agent significantly affected the performance of the elastomer.In particular,,POSS-SH as the cross-linking agent with a cage structure significantly increases the tensile strength of the elastomers.As the amount of cross-linking agent increased,the tensile strength also increased.Under the conditions of ultraviolet light and heating,the chopped elastomer could be repaired with a healing efficiency of>70%.In addition,the elastomer could be used as an adhesive for glass bonding,which can withstand a weight of 200 g.Moreover,the bonding is reversible,indicating theirgood application prospects in terms of reversible adhesives.