EFFECTS OF NANOCLAY CONTENTS ON THE PROPERTIES OF WATER-BASED COATING

Abstract

Different loadings of nanoclay, namely 2, 4, 6, 8 and 10% were mixed into water based polyurethane by homogenisation process and were coated on rubberwood panels. Effects of the incorporation of nanoclay on the chemical, thermal properties, adhesion and mechanical properties of the wood coatings were investigated. Fourier transforms infrared analysis revealed that the polyurethane structure did not change by the addition of nanoclay. Thermogravimetric analysis showed that the coatings added with nanoclay possessed higher residual masses. Decomposition temperature of the coatings added with 2, 4 and 6% nanoclay increased, but decreased when higher loadings were used, probably attributed to the nanoclay agglomeration effect. Impact and scratch resistance of the coatings were improved by the addition of up to 6% nanoclay. On the other hand, abrasion resistance of the coatings was improved when 2% nanoclay was added but started to decrease when 4% nanoclay were used. Moreover, the addition of nanoclay slightly reduced the transparency of the water based coating. Therefore, addition of 2% nanoclay would be sufficient to obtain satisfying results as higher nanoclay content did not result in further improvement of the properties.