Influence of Cow Bone Particle Size Distribution on the Mechanical Properties of Cow Bone-Reinforced Polyester Composites

This work was carried out to investigate the influence of cow bone particle size distribution on the mechanical properties of polyester matrix composites in order to consider the suitability of the materials as biomaterials. Cow bone was procured from an abattoir, washed with water, and sun-dried for 4 weeks after which it was crushed with a sledge hammer and was further pulverized with laboratory ball mill. Sieve size analysis was carried out on the pulverized bone where it was sieved into three different sizes of 75, 106, and 300？ m sieve sizes. Composite materials were developed by casting them into tensile and flexural tests moulds using predetermined proportions of 2, 4, 6, and 8%. The samples after curing were striped from the moulds and were allowed to be further cured at room temperature for 3 weeks before tensile and flexural tests were performed on them. Both tensile and flexural strength were highly enhanced by 8 wt% from 75？ m while toughness was highly enhanced by 6 and 8？wt% from 300？ m. This shows that fine particles lead to improved strength while coarse particles lead to improved toughness. The results show that these materials are structurally compatible and are being developed from animal fibre based particle; it is expected to also aid the compatibility with the surface conditions as biomaterials. 1. Introduction As in other areas of biomedical research, nature is seen in the area of biocomposites as a guide to design new materials [1]. Mimicking the solutions found in natural materials is one of the most promising ways to reach the target set of properties needed in implant materials. Ideally, a replacement material should mimic the living tissue from a mechanical, chemical, biological, and functional point of view. It is very difficult to combine all these properties in only one material. Generally, tissues are grouped into soft and hard tissues. Bone and tooth are examples of hard tissue whereas skin, blood vessels, and cartilage are examples of soft tissue. Accordingly, hard tissues are intended to support loads, being stiffer (higher elastic modulus) and stronger (higher tensile strength) than soft tissues. On the other hand unreinforced polymers are typically more ductile but are not stiff enough to be used to replace hard tissues in load-bearing applications. Nevertheless, polymer based composites can be designed to meet stiffness and strength requirements for hard tissue substitution [2]. Nowadays research in polymer science and technology is mainly focused on composites made from renewable resources [3]. Biocomposites from