Water absorption behavior of heat-treated and untreated red balau saw dust/LDPE composites: Its kinetics and effects on mechanical properties

Abstract

The hygroscopic nature of wood limits the use of wood thermoplastic composites (WTC) in outdoor industrial and domestic applications. To reduce this tendency, red balau saw dust was heat treated at 180 and 200°C for 1 h and compounded with Low Density Poly(ethylene) (LDPE) into 20 and 37 wt% and then molded into test specimens by injection molding. Samples were immersed in distilled water at room temperature for 4 months. Heat-treated wood composites showed remarkable water resistance relative to untreated ones. Wood composites made from wood treated at 180 and 200°C exhibited almost similar water absorption pattern. Reduced water absorption of heat-treated wood composites relative to untreated ones indicates that heat treatment has resulted in a degree of modification of the wood. Most of the composites displayed the Fickian mode of water absorption with n values close to 0.5. Also, the diffusion coefficient reduced with wood content in untreated wood composites due to interaction of water with the polar groups in wood through hydrogen bonding. Untreated wood composites exhibited poorer mechanical properties with water immersion as a result of degradation due to moisture. The mechanical properties of the heat-treated wood composites were not adversely affected with water absorption. Therefore, heat treatment can reduce the proneness to water absorption in WTCs and alleviate the detrimental effects on mechanical properties.

Biodegradable green composite film developed from Moringa Oleifera (Sahajana) seed filler and PVA: Surface functionalization, characterization and barrier properties

“…Therefore, in high humidity, water sensitivity will increase leading to higher moisture absorption. 79…”

“…Therefore, in high humidity, water sensitivity will increase leading to higher moisture absorption. 79 Figure 6((a) and (b)) shows that moisture absorption of MOSF-PVA composite immersed in distilled water is higher than in saline water. This is because of salt molecules which lower the action of water molecules and results in accession of salts particles on the surface of sheet which could further obstruct the water uptake.…”

A Study on the Effect of Construction and Demolition Waste (CDW) Plastic Fractions on the Moisture and Resistance to Indentation of Wood-Polymer Composites (WPC)

“…The solutions for the improved moisture resistant properties are a correct coupling agent [7,10], or an additive such as silane treatment that decreases water uptake with increasing concentration [12]. Filler modification, such as heat treatment, can also reduce water absorption due to its reduced hydrophilicity [13]. The swelling of materials has a connection with water absorption, but the polymer also has an influence on the moisture behavior.…”

Impact of water saturation on the tensile and thermal properties of heat-treated mangrove/high-density polyethylene composites

“…23,24 Jana and Prieto 25 reported that although the addition of coupling agents on WPCs lowers the rate at which of moisture diffuses into composite, adverse effects are noticed on their tensile and impact strength. Furthermore, Lafia-Araga et al 26 discovered that heat-treated wood composites exhibited lower tendency to water absorption as a result of the reduced hydrophilicity imparted to the wood by heat modification.…”