Natural weathering effects on the surface morphological and physicochemical properties of radiation curable coatings in tropical climate

Abstract

The purpose of this research is to discover the effects of natural weathering on palm oil-based and petrochemical-based film coatings. The film coatings were prepared using the radiation curing approach via cross-linking. Three palm oil-based resins with TiO2 nanoparticle loading were developed: EPOLA, EPOLA-OPV, and POBUA. The petrochemical-based coatings were also developed to compare the performance of natural and synthetic coatings. The coatings were exposed to natural weathering for up to 60 days at varied angles of 0°, 45°, and 90°. The effect of natural weathering conditions on the surface morphological, physiochemical, and also flexural characteristics of coatings, as well as the discoloration visual inspection and the growth of mould or fungus on the tested specimen, was studied. The results showed that natural weathering exposure induced severe discoloration and deterioration of the polymer network structure of the coatings due to photo-oxidation reaction and the presence of fungi. Overall, palm oil-based coatings deteriorate slower than petroleum-based coatings, especially at a 90° angle. This study indicated that bioresources-based palm oil has a significant potential for interior wood varnish applications due to its superior qualities over synthetic-based coatings.