Tawakkal, I, Cran, Marlene ORCID: 0000-0002-6000-8093 and Bigger, Stephen W ORCID: 0000-0002-0923-2751 (2014) Characteristics of active natural fibre reinforced poly(lactic acid) composites. In: 19th IAPRI World Conference on Packaging, 15 June 2014-18 June 2014, Melbourne, Victoria.

Abstract

The use of bio-based polymers as alternatives to synthetic polymers has increased extensively in recent years for a wide range of applications. Food packaging, in particular, has seen a growth in the use of materials derived from natural and renewable resources such as poly(lactic acid) (PLA). In many cases, however, the initial costs associated with new technologies to produce biopolymers that rival synthetically derived materials are typically high so new techniques must be sought to reduce costs without compromising material properties. Naturally sourced fibres such as kenaf are often used as cost-reducing fillers for PLA. In some cases the fibres can be treated by alkalization to improve the compatibility with the polymer matrix. This work explores the thermal and mechanical properties of PLA composites incorporated with treated or untreated kenaf fibres (kenaf) together with the addition of thymol, a natural antimicrobial substance. Composites of PLA incorporated with 30% w/w kenaf and 10% w/w thymol were prepared and compared with control systems containing either no kenaf or no thymol. The composites containing treated kenaf had significantly higher tensile strength than composites prepared with untreated fibres. Micrograph images of the fracture surface revealed better adhesion between the treated fibres and the matrix was achieved resulting in improved reinforcement of the composite. In addition, composites containing thymol demonstrated lower tensile strength than those without thymol suggesting a possible plasticizing effect in the presence of the additive. Thermal analysis by differential scanning calorimetry showed similar trends for composites containing treated and untreated fibres with decreases in the glass transition temperature, cold crystalline temperature, melting temperature and melting enthalpy with the addition of thymol. The results suggest that composites containing treated kenaf in particular have a potential for the development of food packaging materials.

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