EFFECT OF GRAPHENE OXIDE ON MECHANICAL, THERMAL AND PHYSICAL PROPERTIES OF IMPACT MODIFIED POLY(LACTIC ACID) NANOCOMPOSITES

Abstract

The advantage of nanofillers such as graphene oxide (GO) is the ability to improve several properties of polymers at relatively small amount of loadings. The objective of this study is to investigate the effect of GO on mechanical, thermal and physical properties of impact modified polylactic acid (PLA) nanocomposites. The incorporation effect of core shell rubber (CSR) as impact modifier into the PLA and PLA/GO composites is investigated. In this study, the weight ratio of PLA:CSR was fixed at 95:5 wt %. Different GO contents (0, 0.5, 1.0, 2.0 phr) was then incorporated into the PLA/CSR sample. From mechanical properties analysis, it was found that the presence of CSR causes a slight reduction in the flexural properties. The addition of GO enhanced the flexural properties with an increment of 41.6% and 11.9% for flexural strength and modulus respectively. Thermogravimetric analysis showed that CSR decreased the degradation temperature of PLA while GO improved the thermal stability of the nanocomposites. The potential of GO in improving thermal stability of PLA was highlighted by the glass transition temperature and melting temperature shifting to a higher temperature. Physical properties were analyzed by soil burial degradation test and water absorption test. Soil burial test showed insignificant changes of weight loss as compared during the initial burial period. The water absorption test is at 30℃ and 50℃ immersion temperature. At 30℃, the results highlighted the superior effect of GO due to its hydrophilic properties. At higher temperature, the amount of water absorbed by PLA and its nanocomposites was higher due to swelling structure of PLA. The results of soil degradation showed that PLA has slow degradation in soil. In conclusion, incorporation of GO at low content into impact modified PLA showed appreciable improvement in the mechanical, physical, and thermal properties of impact modified PLA. This study contributes to the development of advanced bio-based composites.