Ethylene vinyl acetate and ethylene vinyl alcohol copolymer for thermal spray coating application

Ethylene vinyl acetate (EVA) copolymer with varying vinyl acetate (VAc) content, viz. 18%, 28% and 40% has been hydrolyzed using alcoholic NaOH solution. Fourier Transform Infrared Spectroscopy (FTIR) analyses of hydrolyzed polymer showed the presence of both OH group and acetate group indicating that the EVA has been partially hydrolyzed. Differential Scanning Calorimeter (DSC) and Thermo Gravimetric Analyzer (TGA) of EVA and hydrolyzed EVA showed large difference in melting and decomposition temperature, respectively. Hydrolyzed EVA showed higher tensile strength and elongation at break compared to corresponding EVA. Blends of different grades of EVA and ethylene vinyl alcohol (EVAI) with low density polyethylene (LDPE) were applied on grit blasted mild steel surface by flame spray technique. FTIR analysis of blends before and after coating,showed no degradation during flame spray. Measurement of adhesion strength of these coating showed that adhesion strength increased on hydrolysis of EVA. (C) 2008 Elsevier B.V. All rights reserved.