Development of poly(Lactic acid) filled with basalt fibres and talc for engineering applications

The development of renewable resource based and inherently biodegradable polymers as well as their composites are one of the most important research fields nowadays in polymer science. Poly(Lactic Acid) (PLA), as the most promising biodegradable polymer has the potential to replace even engineering composite materials by reinforcing it with natural plant fibres or mineral fibres like basalt. However, one major drawback is its low heat deflection temperature (HDT, ~55°C) caused by its slow crystallization kinetics and thus low crystallinity of the final product. This feature also retards the usage of PLA in composite materials for elevated temperature applications. At the same time, nucleating agents like talc can be used to enhance crystallinity and thus HDT. In this paper basalt fibre reinforced and talc filled PLA composites were prepared by extrusion followed by injection moulding. The results showed that by combining the stiffness increasing effect of basalt fibres as well as the crystallinity increasing effect of talc, a composite with both high mechanical properties and high HDT could be produced.