The effect of filler content and chemical modifications on properties of coconut shell regenerated cellulose biocomposite films

Abstract

The coconut shell (CS) regenerated cellulose (RC) biocomposite films were produced with CS and microcrystalline cellulose (MCC) using N.N-dimethylacetamide/lithium chloride by solution casting technique. The effect of CS content and different types of chemical modifications using butyl methacrylate acid (BMA), lactic acid (LA) and acetic acid (AA) on tensile properties, X-ray diffraction, morphology, thermal properties and FTIR were investigated. The addition of CS into the regenerated cellulose matrix increased the tensile strength and modulus of elasticity up to 3 wt% of CS content but reduced at 4 wt% of CS. The elongation at break of CS-RC biocomposite films reduced with increasing CS content up to 3 wt% and increased at 4 wt% of CS. The crystallinity index (CrI) and thermal properties also increased with the incorporation of CS content up to 3 wt% and reduced at 4 wt%. The morphological study of CS-RC biocomposite films exhibited at 3 wt% CS content has better dispersion into the RC matrix. The decomposition at maximum temperature (Tdmax) and residue of CS-RC biocomposite films increased with increasing of CS content. Weight loss at temperature 300 and 600 °C decreased with increment of CS content in RC biocomposite films. The chemical modifications of CS-RC biocomposite films improved crystallinity index, tensile and thermal properties of CS-RC biocomposite films at 3 wt% of CS content. Treated CS-RC biocomposite films with BMA, LA and AA exhibit higher tensile strength, modulus elasticity, crystallinity index and thermal stability compared to the untreated CS-RC biocomposite films. The better interfacial interaction between the CS and RC matrix was supported by SEM study which showed smooth surface on the tensile fracture surface of treated RC biocomposite films. The FTIR spectra of treated CS-RC biocomposite films indicated the formation of esterification reaction between CS and chemical modifying agent. The CS treatment with AA has the highest tensile properties and CrI compared with the treatment with LA and BMA of biocomposite films. However, the better thermal stability of CS-RC biocomposite films was found with CS treated with BMA.