EFFECT OF SILANE-BASED COUPLING AGENTS AND ACRYLIC-ACID BASED COMPATIBILIZERS ON MECHANICAL-PROPERTIES OF OIL PALM EMPTY FRUIT BUNCH FILLEDHIGH-DENSITY POLYETHYLENE COMPOSITES

The mechanical properties of composites consisting of high-density pol yethylene (HDPE) and oil palm fibrous wastes-that is, empty fruit bunc h (EFB)-have been investigated. Tensile modulus showed an increase, wh ereas tensile strength, elongation at break, and impact strength decre ased with increasing filler loading. The strong tendency of EFB to exi st in the form of fiber bundles and the poor filler-matrix interaction is believed to be responsible for the poor strength displayed by the composites. Attempts to improve these properties using two types of co upling agents, that is, 3-aminopropyltrimethoxysilane (S-APM) and 3-am inopropyltriethoxysilane (3-APM) and two types of compatibilizers, pol y(propylene-acrylic acid) (PPAA) and poly(propylene-ethylene-acrylic a cid), (PPEAA), are described. While almost all chemical treatments inc reased the stiffness of the composites, limited improvement has been o bserved in the case of tensile strength. This have been attributed to the presence of fiber bundles that remain intact even after several ty pes of chemical treatment have been carried out. Thus, the role of EFB as reinforcing agent is not fully realized. Scanning electron microsc opy (SEM) micrographs revealed that the main energy-absorbing mechanis ms contributing towards toughness enhancement is through the fiber bun dle pull-out process. (C) 1998 John Wiley & Sons, Inc.