Fracture toughness of flax braided yarn woven PLA composites

Abstract

Flax fiber braided yarn plain woven fabric reinforced Poly Lactic Acid (PLA) bio-composites are fabricated using film stacking and hot-press compression molding method. Effect of fiber weight fraction on tensile and fracture properties of the bio-composites is studied and fractured surfaces are analyzed using scanning electron microscope (SEM) images. It is found that tensile modulus and strength increases by 62.11 and 59.75% respectively for 35 wt.% of the braided fabric reinforcement compared to pristine PLA. Fracture toughness study is performed on single-edge-notched-bend (SENB) specimens using three point bending method. It is found that plane-strain fracture toughness (K_IC) and strain energy release rate (G_IC) values of the PLA composites are 71.61 and 124% higher than pure PLA for 35 wt.% braided fabric reinforcement. K_IC values of the braided fabric reinforced PLA composites are much high compared to similar natural fiber composites reported in literature. This is attributed to high resistance offered by the interweaving yarns of the braided fabric hence more energy is required to begin crack propagation compared to other typical forms of reinforcement.

Keywords:

• Braided yarn fabric
• PLA composites
• tensile properties
• fracture toughness

Acknowledgments

Authors wish to acknowledge Professor Narendranath, Material Characterisation Lab, NITK Surathkal, for providing testing facilities, and Prof. S M Kulkarni, FIST Composite Centre, NITK, Surathkal, for providing composite fabrication facilities.

Disclosure statement

As a corresponding author of this manuscript and on behalf of coauthors, I would like to declare that there is no conflict of interests regarding the publication of this work. No potential conflict of interest was reported by the author(s).