The Synthesis And Property Of Boron Containing Silicone Adhesion Promoters For Addition-cure Silicone Rubber

Addition-curable liquid silicone rubber(ALSR)is a kind of polydimethylsiloxane with Si-O-Si as the backbone.It has the characteristics of controllable curing speed,no by-product formation in the reaction process and deep curing.The vulcanized silicone rubber is nontoxic,transparent and has good weather resistance and electrical insulation,so it is widely used in the field of electronic and electrical equipment industry.However,a large number of non-polar groups gather on the surface of vulcanized silicone rubber,which shows a low surface energy and poor adhesion performance to substrates.Therefore,it does not play a good role in protecting electronic appliances,which greatly limits the further application of silicone rubber.In order to improve the adhesion strength of silicone rubber,especially the adhesion strength of silicone rubber to poly-phthalamide PPA and copper,Ph BSi O?Me BSi O and EBSi O were synthesized in this paper.The effects of adhesion promoters on adhesion of silicone rubber to copper plate and poly-phthalamide PPA were studied.The main contents and results are as follows:(1)A boron-containing adhesion promoter Ph BSi O with a high refractive index was prepared by non-hydrolytic sol-gel reaction from Phenylmethyldimethoxysilane(PDMS),Vinylmethyldimethoxysilane(VDMS)and boric acid with basic anion exchange resin as the catalysis.The synthesis process of Ph BSi O was discussed and optimized.The structure of the Ph BSi O was characterized by FT-IR and gel permeation chromatography.The influence of Ph BSi O on the adhesion strength of silicone rubber was investigated by shear strength test and scanning electron microscope(SEM),and the effect of Ph BSi O on the transmittance of silicone rubber was further studied.The results show that the molecular weight,molecular weight distribution index,viscosity and refractive index of the prepared Ph BSi O are 497,1.102,28.3 m Pa·s,respectively.When the addition amount of Ph BSi O is 3.0 phr,the adhesion strength of silicone rubber to poly-phthalamide PPA is 0.761 MPa,which is 145%higher than that of silicone rubber without adhesion promoter.The addition of Ph BSi O has little effect on the light transmittance of silicone rubber and still maintains high transmittance;(2)A boron-containing adhesion promoter Me BSi O with a low refractive index was synthesized via non-hydrolytic sol-gel reaction from dimethoxydimethylsilane(MDMS),Vinylmethyldimethoxysilane(VDMS)and boric acid under the catalysis of basic anion exchange resin.The optimal synthesis process was explored.The structure of Me BSi O was characterized by FT-IR and gel permeation chromatography.The influence of Me BSi O on the adhesion property of silicone rubber was investigated by shear strength test and scanning electron microscope(SEM),and the effect of Me BSi O on the transmittance of silicone rubber was further studied.The results show that the molecular weight,molecular weight distribution index,viscosity and refractive index of the prepared Me BSi O are 425,1.093,40.2 m Pa·s,respectively.When the addition amount of Me BSi O is 3.0 phr,the adhesion strength of silicone rubber to poly-phthalamide PPA is 0.809 MPa,which is 161%higher than that of silicone rubber without adhesion promoter.The addition of silicone rubber has little effect on the light transmittance of silicone rubber and still maintains high transmittance;(3)An adhesion promoter EBSi O contained epoxy and boron was fabricated through non-hydrolytic sol-gel reaction with Phenylmethyldimethoxysilane(PDMS)?boric acid??-glycidoxypropylmethyldiethoxysilane(EDES)and Vinylmethyldimethoxysilane(VDMS)as raw materials under the catalysis condition of basic anion exchange resin.The optimal synthesis process was discussed.The structure of EBSi O was characterized by FT-IR,~1H-NMR and gel permeation chromatography.The influence of EBSi O on the adhesion performance of silicone rubber was investigated by shear strength test and scanning electron microscope(SEM),and the effect of EBSi O on the transmittance of silicone rubber was further studied.The results show that the molecular weight,molecular weight distribution index,viscosity and refractive index of the prepared EBSi O are 771,1.689,56.6 m Pa·s,1.5168 respectively.When the addition amount of EBSi O is 1.0 phr,the adhesion strength of silicone rubber to poly-phthalamide PPA and copper plate are 1.691 MPa and 3.163 MPa,which is 257%and 392%higher than that of silicone rubber without adhesion promoter.The content of EBSi O has little effect on the light transmittance of silicone rubber and still maintains high transmittance;(4)Through the shear strength test,the influence of adhesion promoter on the adhesion of silicone rubber was investigated,and the adhesion mechanism of adhesion promoter to improve the adhesion of silicone rubber was explored,and the adhesion mechanism model was established.