Synthesis,Hydrolysis Activity Of ?-Silanes And Their Application In Room Temperature Vulcanized Silicone Rubber

The one-component room temperature vulcanized silicone rubber has the characteristics of high temperature vulcanized silicone rubber such as heat resistance,low temperature resistance,compressed permanent deform-ability,ozone resistance,weather fastness,electrical properties,chemical resistance,water vapor resistance,radiation resistance.And it also has other features including simple manufacture,convenient usage,wide variety,on-site molding,wide application and so on.Then it is used in aerospace,electronics,textiles,construction,etc.Room temperature vulcanized silicone rubber consists of gum,crosslinker,catalyst,filler and auxiliary.Crosslinker is the vital factor to affect the curing time,tack-free time,thermal stability and mechanical properties.The ketone-oxmie silane is used as crosslinker in one-component room temperature vulcanized silicon rubber.For example,the silicone rubber obtained by usual crosslinker(y-amine silanes)has long curing time,which makes it need toxic mental catalysts.Then this would made silicone rubber possess bad thermal stability,mechanical properties or toxic.Hence,it is important to find one crosslinker to prepare silicone rubber possessing good properties,especially without toxic catalysts.The density function theory(DFT)showed that a-amine ketoximesilanes(a-AKSs)possessed high hydrolysis activity compared with y-AKSs.Consequently,we prepared a series of a-AKSs with different functional amine groups used as self-catalytic crosslinkers in one-component room temperature vulcanized silicone rubber.a-AKSs were characterized by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(NMR).The hydrolysis activity of ?-AKSs was determined by conductivity measurement and FT-IR.Here,the tack-free time of silicone rubber was affected by not only hydrolysis activity but also concentration and steric hindrance of crosslinkers.Finally,we prepared silicone rubber possessing good thermal stability and mechanical properties,especially without toxic catalysts.In addition,we synthesized mercapto alkoxy silanes and prepared a series of siloxanes with thioether groups by the thiol-ene click reaction,which could offer an efficient and simple method to produce new silane coupling agents with thioether.