Plant fibre reinforced polymers: where do we stand in terms of tensile properties?

Plant fibres have a unique set of properties ranging from being stiff and brittle, such as hemp and flax, to more ductile, such as coir, c ombining these properties with their cost and availability makes them attractive alternative reinforcements for the production of greener composites . This article reviews the tensile properties of various plant fibre or plant based natural fibre - reinforced polymer s reported in the literature . We critically discuss the use of plant fibres as reinforcement for the production of bio - based , renewable or green polymer composites , showing t he evolution of the properties of plant fibre composites. The reported tensile properties of plant fibre - reinforced polymer composites are compared against various renewable and n on - renewable engineering/commodity polymers as well as the tensile properties of commercially available randomly oriented glass fibre - reinforced polymers (GFRP). G reen composites containing random short plant fibres do have similar properties to randomly oriented GFRP at a lower overall part weight. U nidirectional plant fibre - reinf orced polymers offer better performance than randomly oriented GFRP and could have the potential to be adapted in applications requiring even higher mechanical performance, especially in areas where the use of costly synthetic fibres might be less attracti ve . Furthermore, plant fibres can also be regarded as effective fillers to replace more expensive polymer s and improve the green credential s of final composite parts. These features may motivate the industry to introduce more plant fibre - based products to the market