乙烯基倍半硅氧烷的结构及其膜材料的性能

Study on structures and properties of coating film based on silsesquioxanes derived from vinyltrimethoxysilane (VMS)

以乙烯基三甲氧基硅烷(VMS)和正硅酸四乙酯(TEOS)为原料,利用溶胶-凝胶法制备了乙烯基倍半硅氧烷VS及TEOS改性的VS(VST).以VS和VST为中间体,用浸涂法制备了杂化膜m-VS和m-VST.通过红外光谱和质谱对VS的结构进行了表征.用扫描探针电镜、扫描电镜研究了膜的形貌及其膜厚,并通过DSC、TGA、纳米压痕测试及腐蚀试验,对VS和VST杂化膜的热力学、力学及防腐性能进行了研究.结果表明:合成的VS是含多羟基的低聚物,VST杂化膜的Tg可达129 8℃,热失重温度337 5℃,耐电化学腐蚀,w(TEOS)=20%杂化膜体系的性能最佳.

Vinyl-silsesquioxanes (VS) derived from hydrolytic condensation of vinyltrimethoxysilane (VMS) and modified with tetraethoxysilane (TEOS) (VST) were prepared by sol-gel process. The VS structural characteristics were identified by Fourier transform infrared (FTIR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOP MS). The ormosil thin films based on VS and VST (m-VS and m-VST) were coated on glass by the dip-coating method. The morphology and thickness of the film were characterized with a scanning probe microscope (SPM) and scanning electron microscope (SEM) device. The film properties of thermodynamics, mechanics and electrochemical corrosion were characterized and studied with differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), Nano-Indenter (NI) device and electrochemical impedance spectroscopy (EIS). The results show that the VS was a kind of polyhedral oligomeric silsesquioxanes (POSS) with 1-4 hydroxide, the film with 20% TEOS fraction had the optimum mechanic and corrosion resistance properties, the glass transition temperature was up to 129.8°C, and the weight losses temperature is 337.5°C.