Multilayer cotton fabric bio-composites based on PLA and PHB copolymer for industrial load carrying applications

The thermo-mechanical and impact behavior of bio-based polymers reinforced with a multilayer cotton fabric were determined and assessed for the potential use in building, furniture or automotive applications. The measured properties were compared to other composites with similar natural fabric content or to international standard requirements. Flexural properties of PLA composites fully satisfied the requirements for heavy duty load-bearing boards in humid condition (EN 312 standard), while the PHB copolymer composites still satisfied the conditions for load-bearing boards. The HDT evaluation through the dynamic mechanical thermal analysis revealed the great increase (+53 °C) in the temperature for PHB composites that reached 123 °C, potentially extending their application fields to automotive applications. For this focus, the Charpy impact strengths were also investigated. One of the highest values reported in the literature (54.5 kJ/m2) was reached with PHB, superior to what is commercially used for the interior part of the cars. Furthermore, an epoxy functional additive was employed and was found to reduce the void content and increase the flexural properties and the impact strength.