Preparation And Application Of Smooth Polymethylsesquisiloxane Powders

Silicone elastomer contains Si-O-Si chain segments which can provide a sense of slip and elasticity because of its cross-linked network structure.Polysilsesquioxane powder is a kind of highly crosslinked network structure.These powders are spherical and have good dispersibility.Based on this,this paper prepared a type of polymethylsilsesquioxane powders which possess good smoothness and dispersion?H-PMQS?.We used the physical or chemical coating method to get H-PMQS.The research contents of this paper are as follows:?1?The polymethylsilsesquioxane powder?PMQS?was prepared through the method of hydrolysis and condensation with methyl triethoxysilane?MTES?as raw material.And the structure of PMQS was characterized by Fourier Infrared?IR?,scanning electron microscopy?SEM?and thermogravimetric analysis?TGA?.The effects of different preparation conditions on yield,morphology and particle size of PMQS were investigated.And the results showed that a series of PMQS with good sphericity and uniform dispersion were prepared when the reaction temperature was 50 ?,systems p H values was 10,reaction time was 8 h,m?ethanol?:m?H₂O?=1:1.4.Under these conditions,the yield of PMQS was up to 36 %,its average particle size was 4.5 ?m.In addition,PMQS was so strong hydrophobicity that its static contact angle was about 165o.?2?With hydrogen containing silicone oil?PHMS-0.08%?,vinyl silicone oil?VPS?as raw materials,the solid silicone elastomer?SSE?was prepared by silicon hydrogen addition reaction under the action of platinum.A type of silicone elastomer gel?SEG?acted as coating material was got by dissolving SSE into D4.The structure of SSE and SEG were characterized by IR and SEM.The effects of reaction conditions on the yield of SSE were discussed.And the results showed that with reaction temperature was 75 min,reaction time was 30 min,The amount of catalyst used is 20 parts per million,n?Si-H?: n?Vinyl?=1:1.2,the yield of SSE was up to 98.53 %.In physical coating,SEG was used as a surface modifier for PMQS in order to get a type of smooth polymethylsilsesquioxane?Hp-PMQS?.Its performance was characterized by SEM,nano particle size analyzer and static contact angle instrument.The coating conditions were discussed that when m?PMQS?:m?SEG?=8:2,drying temperature was 70 ?,ultrasonic time was 30 min,setting was 120?×30min,Hp-PMQS presented good microspheres and smoothness.Under such conditions,the average particle size of Hp-PMQS was 6 ?m while its size distributed a wide range.Besides,the surface energy of Hp-PMQS was decreased and its contact angle was 152o.Furthermore,a coating layer can be seen on the surface of Hp-PMQS from SEM,but not coated uniformity.?3?PHMS-0.5%,vinyltriethoxysilane?VTES?were used as raw materials to prepare H-VTES as modifier by hydrosilylation reaction.The structure of H-VTES was characterized by IR.With MTES and H-VTES as raw materials,a type of smooth polymethylsilsesquioxane powder?Hc-PMQS?was prepared by chemical coating method.Its structure was characterized by IR,1H-NMR and SEM,while its performance was tested with nano particle sizer and static contact angle.The influence of different reaction conditions were researched.And results showed that Hc-PMQS was prepared when the dosage of polyethylene glycol?PEG?was 2 % of the mass of raw materials,the dropping time of water was 1.5 h,the content of Si-H was 0.5 % and m?MTES?: m?H-VTES?was 8:2.Under these conditions,the yield of Hc-PMQS was up to 55.8 %,its average particle size was about 4?m,and its contact angle was 160o.Hc-PMQS/ASO emulsion was prepared in order to used as fabric finishing agents.Its average particle size was 226.1nm and its zeta potential was +20.5m V.Cotton fabric was treated with Hc-PMQS/ASO emulsion,and the effects of different factors on the properties of fabric were investigated.The results showed that the fabric had good elasticity hydrophobic after finished by Hc-PMQS/ASO emulsion at the condition of m?SEG?: m?ASO?=1:9,Hc-PMQS/ASO bath concentrationwas 0.3 %,baking temperature was 145 ?.Here,the finished cotton fabric reflected a good application with its white degree was 82.5 %,the wrinkle recovery angle was 290.3o and its static contact angle was 149.7o.It can be seen that the Hc-PMQS microspheres on the surface of the treated fibers can increase the surface roughness and slip elasticity of the fabric.