Comparative study of effect of different coupling agent on mechanical properties and water absorption on wheat straw-reinforced polystyrene composites

The present work deals with the effect of various treatments on the mechanical properties and water absorption of wheat straw (WS)-reinforced polystyrene (PS) composites. Four different surface treatments of the filler, that is, alkali treatment of WS by 20% sodium hydroxide (NaOH) solution, maleic anhydride (MA) treatment of WS by 2% MA solution, WS treatment with 1% silane (ATS) and WS treatment with 20% NaOH and 1% silane, with 5-25% filler loading were carried out. There is an enhancement in tensile modulus, impact strength and water absorption and a decrease in tensile strength of WS fiber-filled PS composite with an enhancement in fiber loading when it is treated with 20% NaOH, 2% MA, and 1% silane. There is an enhancement in tensile strength, tensile modulus, Izod impact strength, and water absorption value when the WS fiber is treated with 20% NaOH and 1% silane, with an enhancement in fiber loading. Treatment with 20% NaOH and 1% silane exhibits better results as compared to the rest of the surface treatments.