Soil Degradation Characteristics of Short Sisal/PLA Composites

Abstract

Abstract Fully biodegradable composites were made-up of short sisal leaf fiber as a reinforcing member and Polylactic acid (PLA) as matrix. The biodegradation rate of untreated sisal/PLA (UTS/PLA) and successive alkali treated sisal/PLA (10TS/PLA) composites was found by evaluating the weight loss, mechanical strength and surface roughness before and after soil burial test. The results revealed that UTS/PLA composites have degraded much rapidly than that of 10TS/PLA composites. It is found that there was a loss in weight of 15.20% for UTS/PLA with 25% of fiber content and weight loss of only 5.56% with 10TS/PLA composites after keeping the samples for 90days in soil. The surface roughness on composites was predicted with ‘Ra’ value and increase in surface roughness of the composite was observed with increase in fiber loading and the increment was slightly high for 10TS/PLA compared to that of untreated fiber composite as well as pure PLA. After burial of composites in the soil for 90days, a huge drop in the tensile strength was observed for both UTS/PLA and 10TS/PLA composites. The drop is 26.5%, 54% and 56.31% for plain PLA, UTS/PLA and 10TS/PLA composites respectively. From the experimentation it is confirmed that PLA and its composites can be subjected to degradation in soil at a reasonable speed and also it is recommended that the amount of degradation within a span of time can be controlled by fiber treatment with alkali as well as fiber loading.