Experimental Investigation into Tribological and Hygromechanical Properties of Rice Stubble Waste Polymer Composites

Utilizing rice stubble waste for the fabrication of composite materials offers a promising opportunity to enhance sustainability in the depleting materials resources. This work investigates the hygromechanical and tribological machinability of chopped rice stubble reinforced polymer composites. The water and alkali pretreated composites are prepared using a weight fraction of 50% and 60% of stubble inside the resin matrix. It is found that the hygro-mechanical and wettability properties got improved with the pretreatment. In order to observe the effect of environmental conditions, the composites were subjected to a temperature of 40 and a relative humidity of 60% for 7 days under the accelerated aging conditions. Using water and alkali treatments, the tensile strength of the environmentally aged specimens increased by ~75% and 45%, respectively. The pretreatment also improved the composite’s hydrophobic behavior, indicated by the rise in the contact angle at ~48%. Subsequent mass gain studies were conducted by placing the specimens in water bath at 25, 50, and 75. The mass gain is reduced by 10% to 15% for the pretreated composite specimens. The wear tests under the dry sliding conditions, followed by microstructural analysis, revealed the enhancement in polymer matrix’s tribological characteristics with the addition of stubble waste.