Improvement of mechanical properties due to increased fibre matrix adhesion in flax fibre reinforced polypropylene

Abstract

Influence of initial fiber length on the mechanical and tribological properties of hemp fiber reinforced plantsderived polyamide 1010 biomass composites AIP Conference Proceedings 1914, 070003 (2017) Abstract. The hydrophilic nature of natural fibres and the hydrophobic behaviour of standard polymers such as polypropylene and other polyolefins are the major cause for the lack of adhesion between fibre and matrix in natural fibre reinforced plastics (NFRP's). To overcome this incompatibility of fibre and matrix, different coupling agents can be incorporated into the compound. Our investigations revealed the bonding capability of three dendritic polyesters and one thermoplastic polyurethane in a flax fibre/PP compound. The treatment with different amounts of coupling agent led to an increase in mechanical properties such as bending strength, tensile strength and most of all CHARPY impact strength. In addition, it was possible to make a correlation between IR spectra and the chemical and physical interactions between fibre, matrix and adhesive. Therefore a relationship between intermolecular forces and mechanical properties could be concluded.

A Review of the Impact Performance of Natural Fiber Thermoplastic Composites

“…The increase of NFTC NI strength by the addition of compatibilizer has been observed in several studies (Sanadi et al, 1994(Sanadi et al, , 1999Karnani et al, 1997;Feng et al, 2001;Li et al, 2001;Lei et al, 2007;Ashori et al, 2008;Beg and Pickering, 2008;Lee et al, 2009;Araujo et al, 2010;Guo et al, 2010;Mohanty and Nayak, 2010;Paul et al, 2010;Malfatti et al, 2017). This is often related to an increase in the fiber-matrix adhesion/compatibility, which leads to higher energy required for crack propagation (Feng et al, 2001;Marcovich and Villar, 2003;Ashori et al, 2008).…”

“…The authors suggested that these results indicated an increased fiber-matrix adhesion and that the energy dissipated through pull-out decreased. Malfatti et al (2017) studied the effect of a range of hot melt adhesive additives on the Charpy UI performance of injection molded 30 wt% flax reinforced PP with and without MAPP coupling agent. Their idea was to improve fiber-matrix adhesion through the addition of dendritic polyesters (DP) or thermoplastic polyurethane.…”