Effect of Wood Species on the Mechanical Properties of Wood Plastic Composites

Abstract

The quality of wood plastic composites (WPCs) is largely influenced by the type and 
properties of the reinforcing fibres, the manufacturing process, and the composition 
of the constituent materials. In particular, the choice of wood species used as filler 
and reinforcement plays a critical role in determining the mechanical performance of 
the final composite. This study investigated the impact of different wood species on 
the mechanical properties of WPCs. The selected wood species included Tectona 
grandis (TGS), Adansonia digitata (ADA), Khaya ivorensis (KHS), Butyrospermum 
paradoxum (BSP), and Gmelina arborea (GMA). These were blended with recycled 
polypropylene at varying filler loadings of 10, 20, 30, 40, and 50 wt%. Mechanical 
properties such as tensile strength, flexural strength, impact strength, and hardness 
were evaluated in accordance with ASTM standards. Among the wood species tested, 
Khaya ivorensis (African mahogany) exhibited a notable tensile strength of 20.44 
N/m² at 30 wt% and the highest flexural strength (44.47 MPa), followed by Gmelina 
arborea (Parrot Beak) at 39.77 MPa and Butyrospermum paradoxum (Shea Butter) at 
38.97 MPa. At 50 wt% filler content, Gmelina arborea and Adansonia digitata 
(Baobab) demonstrated superior hardness values, with Gmelina arborea reaching 
59.03 Hv. In terms of impact resistance, African mahogany and baobab recorded the 
highest values of 0.59 J and 0.55 J, respectively. At 20 wt% filler loading, Tectona 
grandis (Teak), African mahogany, and shea butter exhibited the highest modulus of 
elasticity, with values of 931.42 MPa, 1004.47 MPa, and 1141.21 MPa, respectively. 
These findings underscore the significant influence of wood species on the 
mechanical behavior of WPCs. The selection of suitable wood fibres can therefore 
be tailored to enhance specific performance attributes of the composite, depending 
on the intended application.