Study on plasticizing PLA using natural plasticizers available in Vietnam as a matrix resin for biodegradable PLA/cellulose composites

Abstract

The study's objective was to evaluate the role of epoxidized vegetable oils (EVOs) in the properties of polylactic acid (PLA) and PLA/cellulose composite materials. This study selects EVOs derived from commonly used vegetable oils in Vietnam, namely soybean oil, Cleidiocarpon cavaleriei oil, and linseed oil, as potential plasticizer agents for PLA. In this study, PLA and composite samples will be prepared using the melting method on a co‐rotating twin‐screw extruder. The evaluation of plastic efficiency in PLA is carried out through the XRD, physical properties, and differential scanning calorimetry analysis (DSC). The results show that the effective usage of EVOs agent was demonstrated by a decrease in PLA's Tg values. In particular, the Tg values of PLA‐ESBO, PLA‐ELO, and PLA‐ECCO were 54.8 °C, 52.3 °C, and 51.4 °C, respectively, as compared to the Tg value of PLA at 58.8 °C. In the XRD spectrum, the EVOs change the crystallization structure of PLA. Specifically, the intensity peak at 2θ ≈ 14.6° is markedly reduced in the EVO‐containing sample, while a distinct and intense peak disturbance emerges at 2θ ≈ 16.6°. The utilization of EVOs has been observed to impact the mechanical characteristics of PLA, resulting in a decrease in the tensile strength and an increase in the elongation at break.