Preparation And Properties Of Impact Modified Poly(Lactic Acid)/Kenaf Fiber Composites
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Date
2011-11
Authors
Ghaleb, Zaid Aws Ali
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Publisher
Universiti Sains Malaysia
Abstract
Preparation and properties of impact modified composites from poly(lactic acid) (PLA) and kenaf fiber (KF) was investigated. The first part of this study was to evaluate the effect of impact modifier on the thermal, mechanical and morphological properties as well as biodegradability (natural weathering and soil burial) of PLA. The glass transition temperature (Tg) of PLA in the blends did not significantly change with addition of impact modifier. From dynamic mechanical analysis (DMA), the immiscibility of the blends can be observed. The blends showed two distinct Tgs corresponding to PLA and the impact modifier. The elongation at break and notched impact strength of the blends increased with increasing impact modifier. Morphological study via scanning electron microscopy (SEM) showed the phase separation of the PLA/impact modifier blends, which indicated the immiscibility of the polymer blends. PLA with 20 wt% impact modifier was chosen as a matrix for the second part of this study as it showed the optimum notched impact strength increased 8-folds compared to pure PLA. The second part of this study was to evaluate the effect of 40 wt% KF on the mechanical properties of chosen impact modified PLA (i-PLA). The yield stress, elongation at break, notched impact and fracture toughness of i-PLA were decreased with addition of 40 wt% KF. As compared to PLA/KF composites, i-PLA/KF composites showed lower yield stress, Young’s modulus but higher elongation at break, notched impact strength and fracture toughness than that of PLA/KF composites. i-PLA/KF composites showed 55.5, 3.8, 78.1 and 49.1 % higher respectively for yield stress, Young’s modulus, notched impact strength and fracture toughness than PP/KF composites.
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Keywords
Preparation and properties of impact modified composites , from poly(lactic acid) (PLA) and kenaf fiber (KF)