The effect of filler content and chemical modification on properties of polylactic acid/recycled low density polyethylene/nypa fruticans husk biocomposites

Abstract

Nypa fruticans husk (NFH) filled polylactic acid (PLA)/recycled low density polyethylene (rLDPE) biocomposites had been prepared using Brabender Plasticoder EC PLUS at temperature 180˚C and rotor speed 50 rpm. The effect of NFH content and different types of chemical modifications on tensile properties, morphology, thermal properties and biodegradation of PLA/rLDPE/NFH biocomposites were studied. The various types of chemical modifications such as Polyethylene grafted maleic anhydride (PEMA), 3-Aminopropyltriethoxysilane (3-APE), Methyl methacrylate acid (MMA), Ethylenediaminetetraacetic acid disodium salt-2-hydrate (EDTA), and enzyme were used, respectively. The results showed that the addition of NFH reduced the tensile strength, elongation at break and degree of crystallinity (Xc), whereas the Young‘s modulus and thermal stability of biocomposites increased. The effects of α-amylase on the enzyme biodegradation of PLA/rLDPE/NFH biocomposites showed that the increased of NFH content has increased the biodegradation rate of the biocomposites. The morphology tensile fracture surface of PLA/rLDPE/NFH biocomposites indicates that poor interaction occurred between NFH and PLA/rLDPE matrix. The chemical modifications of NFH resulted positive effect on tensile and thermal properties of PLA/rLDPE/NFH biocomposites. The presence of PEMA, 3-APE, MMA, EDTA, EDTA/Enzyme and 3-APE/Enzyme have increased the tensile strength, Young‘s modulus, degree of crystallinity and thermal stability of biocomposites, whereas the elongation at break decreased. The treated PLA/rLDPE/NFH biocomposites with 3-APE/Enzyme have highest tensile strength, Young‘s modulus, and thermal stability compared to other chemical modifications of biocomposites. However, PLA/rLDPE/NFH biocomposites treated with MMA has highest degree of crystallinity. Meanwhile PLA/rLDPE/NFH biocomposites treated with EDTA exhibited highest rate of biodegradation. The better interfacial interaction between treated NFH and PLA/rLDPE matrix was proven by SEM study. The spectra FTIR indicated that the changes of functional group of treated biocomposites.