透明氧化锌/有机硅纳米复合涂层的研制及性能

Preparation and property of transparent zinc oxide/ organic silicone nanocomposite coating

采用化学改性方法将自制的纳米ZnO颗粒接枝到含氢聚硅氧烷(PMHS)分子链上,以该接枝聚合物(ZnO–PMHS)和端乙烯基聚硅氧烷为反应物,在铂催化作用下合成了一种可用于电子封装的透明有机硅纳米ZnO复合涂层。研究了纳米ZnO含量对涂层力学性能和光学性能的影响,通过扫描电镜、傅里叶变换红外光谱和热重分析,对纳米ZnO改性前后的涂层进行了表征。研究表明,ZnO纳米颗粒通过化学接枝连接到聚合物分子链上;ZnO纳米颗粒的接枝反应改变了复合涂层的折光指数,当纳米ZnO含量为0.06%时,复合涂层在640 nm处的透光率达到80%以上,对300 nm以下的紫外光的屏蔽效率达到90%以上;与未含纳米ZnO的涂层相比,有机硅纳米ZnO复合涂层的耐紫外老化能力提高了5倍,初始热分解温度提高25%,热分解残留质量提高15%,表现出优异的耐热和耐紫外老化性能,满足电子产品的封装要求。

The homemade nano-ZnO particles were grafted to the molecular chain of poly（dimethylhydrosiloxane） （PMHS） by chemical modification method. A transparent organic silicone nano-ZnO composite coating for electronic packaging was synthesized with the graft polymer ZnO-PMHS and vinyl-terminated polysiloxane as reactants under catalytic action of Pt. The effect of ZnO content on mechanical and optical properties of the coating was studied. The coating before and after modifying by nano-ZnO was characterized by scanning electron microscopy, Fouriertransform infrared spectroscopy, and thermogravimetric analysis. It was found that the ZnO nanoparticles are connected to the molecular chain of polymer by chemical grafting. The refractive index of the composite coating ＇s changed by grafting with ZnO nanoparticles. The coating prepared with 0.06wt% nano-ZnO has a transmittance 〉80% at 640 nm and a shielding efficiency 〉90% for ultraviolet below 300 nm, showing a five-times ultraviolet aging resistance, 25% higher initial thermal decomposition temperature, and 15% more residue weight as compared with the coating without nano-ZnO. The organic silicon/nano- ZnO composite coating presents excellent thermal resistance and ultraviolet aging resistance, meeting the packaging requirement of electronic products.