Preparation And Characterization Of Reactive Silanes And Polymers

Silicone products with various excellent properties play an increasingly important role in modern industry.Reactive silanes with high reactivities are widely used organosilicon intermediates,which can be used as reactants to synthesize different kinds of silicone oil,silicone rubber,silicone resin and other organosilicon polymers,and react with other organic compounds and polymers to prepare polymers containing silicon.Reactive silanes and polysiloxanes are usually prepared by hydrosilylation,which need expensive catalyst,strict conditions and protection of special functional groups sometimes.Therefore it is necessary to explore effective synthesis methods of reactive silanes or polysiloxanes.Primary studies on preparation and characterization of reactive silane and polymers were carried out in this paper.Acryloyloxymethyl-terminated polydimethylsiloxane was prepared successfully by a new method.Firstly,acryloyloxymethyldimethylacryloyloxysilane was prepared with(chloromethyl)dimethylchlorosilane and potassium acrylate as reactants,toluene or xylene as solvent at the existence of inhibitor and phase transfer catalyst.Secondly,acryloyloxymethyl-terminated polydimethylsiloxane was prepared through decarboxylation of acryloyloxymethyldimethylacryloyloxysilane and hydroxy-terminated polydimethylsiloxane without catalyst,which has many advantages,such as simple operation,mild reaction conditions and few side reactions.This method avoided using expensive platinum catalyst as catalyst,and could effectively control the polymerization reaction of double bond,the yield of which was high.Polysiloxane-polyether copolymers were prepared via aza-Michael reaction of acryloyloxymethyl-terminated polydimethylsiloxane and polyetheramine without catalyst.Copolymers with different molecular weights could be obtained by using different solvents and molar ratios of NH2 and C=C.1,3-bis(y-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was prepared by alcoholysis-hydrosilylation-hydrolysis method without protection of hydroxy,using dimethylchlorosilane and propenol as reactants.In order to reduce side reactions and improve the alcoholysis yield,the reaction used sodium allylate-propenol mixed solution,solvent that hydrogen chloride does not insolubilize,acid absorber and inert gas such as nitrogen or argon.The hydrosilylation yield could be improved by using catalyst and cocatalyst.1,3-bis(?-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane was prepared through acid hydrolysis of hydrosilylation product.Hydroxypropyl-terminated polydimethylsiloxane was prepared through cationic polymerization of octamethylcyclotetrasiloxane(D4)with 1,3-bis(?-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane as end-capping reagent.Polysiloxane-polyurethane could be prepared' with hydroxypropyl-terminated polydimethylsiloxane and MDI as reactants without catalyst.Polysiloxane-polyurethane with different molecular weights could be prepared by using different solvents such as toluene,THF and DMF and different molar ratios of-OH and-NCO.