Biological properties of nutshell and microcrystalline cellulose (MCC) filled high density polyethylene composites

Purpose: The composites based on natural fibre and wood can be destroyed by fungi attack, even the lignocellulosic materials were used as filler in hydrophobic thermoplastic matrix. The aim of this study was to investigate the effect of microcrystalline cellulose (MCC) and nutshell fibre content on decay resistance of natural fibre composites. Design/methodology/approach: Half of the composite samples were immersed in water for 60 days and then incubated by fungi to investigate the leaching effect on biological resistance. Furthermore, water absorption rate and thickness swelling of samples were determined during water immersing. For this purpose, total nine thermoplastic composites filled different MCC rate (5%, 10% and 15%) and nutshell content (30%) were produced. Decay test were conducted by using a white rot fungus–Trametes versicolor, and a brown rot fungus–Tyromyces palustris, according to EN 113 standard. Findings: Based on findings from this study, weight loss, water absorption rate and thickness swelling correlated with lignocellulosic content in composites. Samples exhibited less than 1% weight loss in decay test and excellent biological resistance against testing fungi. Research limitations/implications: Weight loss (%) and moisture content (%) values of MCC-nutshell HDPE composites after Tyromyces palustris and Trametes versicolor attack were found under 3% and 20%, respectively. Low weight loss values obtained in the study are supposed to be related with the low moisture content. Originality/value: There is not a study dealing with the decay resistance of WPCs produced by a combination of nutshell and MCC fibres. In addition, there is not a substantial study on the effects of MCC/plastic ratio for decay performance of WPCs contained nutshell after long-term leaching test.