Comparative study of polystyrene/chemically modified wheat straw composite for green packaging application

The recalcitrant nature of native wheat straw (WS) biomass results from cellulose, lignin, hemicellulose and some amount of protein embedded together in a composite structure causing poor adhesion to a polymer matrix composite. Adequate pre-treatment can curtail the recalcitrance structure of WS and enhance the susceptible cellulose area to synthesize a green composite. This paper examined the effect of various chemical pre-treatment procedures in improving surface morphology of wheat straw. Moreover, polystyrene (PS), PS (60 wt%)/native WS (40 wt%), PS (60 wt%)/NaOH-treated WS (40 wt%), PS (60 wt%)/HCl-treated WS (40 wt%), and PS (60 wt%)/H2SO4-treated WS (40 wt%) composite films were prepared using solution casting method. The changes in crystalline structure, hydrophobicity, water vapor migration rate, and thermal and mechanical stabilities of synthesized bio-composites were examined. From the results it can be concluded that the alkali-treated WS is highly compatible with the PS and can be used to synthesize a biodegradable composite film for various industrial green packaging applications.