Improved properties of medium-density particleboard manufactured from saline Creeping Wild Rye and HDPE plastic

Abstract

Creeping Wild Rye (CWR), Leymus triticoides, is a salt-tolerant perennial grass used for mitigating the problems of saltilization and alkalization in drainage irrigation water and soil to minimize potential pollution of water streams. In this study, CWR was used as a raw material to manufacture medium-density particleboard. The objective of this research was to characterize the mechanical and water resistance properties of CWR particleboards bonded by four different adhesive levels and compositions, including 4% polymeric methane diphenyl diisocyanate (PMDI), 2.8% PMDI, [1.2% rice bran adhesive (RBA) + 2.8% PMDI] and [20% recycled high-density polyethylene (HDPE) + 2.8% PMDI]. In addition, orthogonal experimental design was employed to optimize three factors (hot-press temperature, HDPE particle size and HDPE content) to achieve desired mechanical and water resistance properties of particleboards bonded by a mixture adhesive. The evaluated mechanical properties of particleboards were tensile strength (TS), modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) strength. Water absorption (WA) and thickness swelling (THS) were measured to determine water resistance properties of the particleboards. Partially replacing PMDI with RBA did not compromise mechanical quality, but deteriorated water resistance properties. The results showed that 30% of PMDI can be replaced by adding 20% HDPE, resulting in particleboard with higher mechanical strength and water resistance than particleboard made without HDPE. It has been concluded that HDPE from recycled plastic bags could be used as an adhesive or additive to partially replace PMDI for making high-quality particleboards.