This study aims to investigate the influence of weather exposure on the physical and mechanical characteristics of rHDPE matriced composites reinforced with zalacca midrib fibers. The specimens were fabricated using the compression molding method into 3 variations which include the neat rHDPE as control as well as the untreated and alkaline-treated zalacca fiber-reinforced rHDPE composites at 30 % vf. Moreover, the weathering exposure was conducted under a tropical climate for 6 months after which all the specimens became chalky and showed significant changes in color. The FTIR results indicated that carbonyl groups of rHDPE emerged due to the weathering exposure while the thermogravimetry test showed no significant change in thermal stability. It was also discovered that their flexural and impact strength were enhanced by the alkaline treatment but the effect diminished after weathering. The micrograph observation showed some gaps between fibers and matrix, breakage of the fibers and matrix bonds, and cracks on matrix around the fibers. Furthermore, the fracture of the neat rHDPE was observed to be more brittle after exposure and this means the neat rHDPE and rHDPE-ZF composites are suitable for indoor applications but not recommended for outdoor uses.
Keywords: weather exposure; rHDPE, zalacca fibers; alkaline treatment; compression molding