Effect of maleated compatibilizer on anisotropic mechanical properties, thermo-oxidative stability and morphology of styrenic based thermoplastic elastomer reinforced with alkali-treated pineapple leaf fiber

Composites of styrenic based thermoplastic elastomer reinforced with pineapple leaf fiber (PALF) were prepared by melt mixing on a two-roll mill, sheeted out with some stretching to preferentially orient the fiber along the machine direction and then compression molded to form a composite sheet. The effects of alkali treatment of PALF surface and compatibilizer loading on thermo-oxidative stability, tensile and dynamic mechanical properties of the composites were investigated. The alkali-treated PALF showed a smooth surface and has higher thermo-oxidative stability when compared with the untreated fiber. The respective increase in thermo-oxidative stability was found for the composites of alkali-treated fiber and alkali-treated fiber with the presence of compatibilizer. The tensile stress in the longitudinal direction clearly increased with fiber loading. The reinforcing performance was clearly improved for the alkali-treated fiber composite system when compared with that of the untreated fiber composite. For the alkali-treated PALF containing compatibilizer system, the longitudinal tensile stress of the composite could be improved further as higher than four times that of the neat matrix. The results of stress ratio anisotropy revealed that the improvement in tensile stress for the treated fiber composite systems was observed in longitudinal direction under stretching up to 250 % strain. The effects of fiber surface treatment and compatibilizer were less significant in the transverse direction. The glass transition temperatures for soft and hard phases of the elastomer matrix were not significantly affected by fiber treatment and compatibilizer loading.