Preparation And Properties Of UV-curable Conductive Coating Modified With Hyperbranched Polysiloxance

Polysiloxanes consists of repeating flexible Si-O-Si bonds,which results in super heating and cooling resistane,excellent physical and chemical stability and corrosivity.Hyperbranched polysiloxane(HPSi)was synthesized by the hydrolyzation of 3-methacryloxypropyltrimethoxysilane with reactive group.Compared with lined polysiloxanes,because of special structure by itself,hyperbranched polysiloxane has considerably lower viscosity,well solubility and favorable rheological behavior.UV-curable conductive coating is one of the most important environmentally friendly painting.However,it has several disadvantages such as rather slowly-curing and badly corrosivity and so on.According to searching for a lot of literatures,hyperbranched polysiloxane is prepared by 3-methacryloxypropyltrimethoxysilane and distilled water with a molar ratio in acidic solution.The typical description for synthesizing epoxy acrylate resin is that E-51 and acrylic acid is catalyzed by triethanolamine.Then we choose synthesized epoxy acrylic resin as the UV conductive coating matrix,graphite power and graphene as conductive fillers.Subsequently,an appropriated amount of epoxy acrylic resin is blended with HPSi and photoinitiator with mechanical stirring at room temperature to form homogeneous liquid.The thermal stability,corrosivity and curing time of this new UV conductive coating are improved.The detailed research and results are summarized that epoxy acrylate resin is synthesized by E-51 and acrylic acid catalyzed by triethanolamine.The structure of epoxy acrylate resin is characterized by FTIR analysis.And the acid value and epoxy value of finished reaction are tested.Then hyperbranched polysiloxane is prepared by 3-methacryloxypropyltrimethoxysilane and distilled water with a molar ratio in acidic solution.The structure of hyperbranched polysiloxane is characterized by FTIR,1HNMR and GPC analysis.Then the viscosity of the objective hyperbranched polysiloxane is tested.The results shows that the amount of the molar ratio of H2O and KH-570 is 1.2,which is objective polysiloxane.The conductive coating is modified with HPSi was synthesized successfully.Then tested for its curing properties,the results shows that elongation of cured films is the reduced tendency,and the tensile strength is increased with little HPSi,showing reduced the trend when added more HPSi into coating.Cured film possed good thermal stability performance,its inereased 60.1? higher than unmodified curing films when HPSi content was 10%.And the curing time decreased from 65s to 45s.The surface resistivity of the film changes with conductive filler content.when the graphite powder content is 1.25%,the surface resistivity of films is 5.237×108?·cm-2,and graphene surface resistivity of the films is 2.0609×109?·cm-2;when the content of is 1.5%,the surface resistivity is 8.5517×108?·cm-2.Compared with graphite powder,the surface resistivity of graphene is 3.1424×108?·cm-2.The corrosivity of the cured film is improved with the increase of HPSi content.Water resistance,acid resistance and salt resistance is best when content of HPSi is 10%,but alkali resistance is best including 12.5%HPSi.