Anticorrosively enhanced PMMA-SiO2 hybrid coatings prepared from the sol-gel approach with MSMA as the coupling agent

作者：Yeh Jui Ming^*; Weng Chang Jian; Liao Wen Jia; Mau Yi Wen

来源：Surface and Coatings Technology, 2006, 201(3-4): 1788-1795.

DOI：10.1016/j.surfcoat.2006.03.011

• PMMA
• polyacrylate-silica
• sol-gel
• corrosion protection

A series of sol-gel derived organic-inorganic hybrid coatings consisting of organic poly(methyl methacrylate) (PMMA) and inorganic silica (SiO2) were successfully synthesized by using 3-(Trimethoxysilyl)propyl methacrylate as a coupling agent. In this work, MSMA is first copolymerized with methyl methacrylate monomer at specific feeding ratio by using benzoyl peroxide (BPO) as initiator. Subsequently, the as-prepared copolymer (i.e., sol-gel precursor) is then cohydrolyzed with various contents of tetraethyl orthosilicate (TEOS) to afford chemical bondings to the forming silica networks, giving a series of hybrid sol-gel coatings. Transparent organic-inorganic hybrid sot-gel coatings with different contents of silica are always achieved. The as-synthesized hybrid sol-gel materials were subsequently characterized by Fourier-Transformation infrared (FTIR) spectroscopy and transmission electron microscopy (TEM).
The hybrid sol-gel coatings with low silica loading (e.g., 5 wt.%) on cold-rolled steel (CRS) coupons were found much superior in anticorrosion efficiency over those of neat PMMA based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current, and corrosion rate in 5 wt.% aqueous NaCl electrolyte. The enhancement of corrosion protection effect of hybrid sol-gel coatings may be due to the increase of adhesion strength of hybrid sol-gel coatings on CRS coupons relative to neat PMMA, which was further evidenced by the Scotch tape test evaluation. The increase of adhesion strength of hybrid sot-gel coatings on CRS coupons may be attributed to the formation of Fe-O-Si covalent bonds at the interface of coating/CRS system based on the FTIR-RAS (reflection absorption spectroscopy) studies. Effects of the material composition on the thermal stability, mechanical strength, wettability, and surface morphology of neat copolymer and a series of hybrid sol-gel materials, in the form of coating/film, were also studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), hardness tests, contact angle measurement, and atomic force microscopy (AFM), respectively.

• 出版日期2006-10-5