Study of the Behavior of Moisture Absorption and Swelling in High Filler Loading Kenaf Core/Bast Polyethylene Composites

Abstract

Abstract One of the major concerns of wood plastic composite for outdoor application is moisture absorption and thickness swelling (TS). This study investigates the effect of temperature on moisture absorption and TS characteristics of kenaf reinforced polyethylene composite (KPeC). The kenaf materials (core and bast) are at a ratio of 60:10 and were treated with 10 % magnesium chloride (MgCl2). For the preparation of composites, the weight ratio of the kenaf filler (containing core and bast) to high-density polyethylene matrix was 70:22 (wt./wt.), and the weight of the coupling agent in the formulation was 3 wt. %. The composites were prepared using a hot compression molding. The effect of temperature and humidity on the properties of the KPeCs were determined following conditioning at different temperature and relative humidity (RH) combinations, namely 20°C-95%RH, 30°C-95%RH, 50°C-95%RH, and soaking in water at 20°C. The KPeCs were conditioned at various combinations of temperature and RH (20°C-95%RH, 30°C-95%RH, 50°C-95%RH, and soaking in water at 20°C) and the effects of these various conditions on the properties of KPeCs were determined. At 95% RH exposure, the moisture absorption and swelling rate of both composites increased as the temperature increased. All KPeCs at different exposures exhibited Fickian behavior except for KPeCControl and KPeC10%-MgCl2 when aged at 20°C-95%RH.