Mechanical, wear and thermal conductivity characteristics of snail shell-derived hydroxyapatite reinforced epoxy bio-composites for adhesive biomaterials applications

This research investigates the effects of snail shell-based hydroxyapatite (HAp) reinforcements on the mechanical, wear, and selected physical properties of epoxy-based composites. The exploitation of these properties was aimed at assessing the suitability and efficiency of the developed bio-composites for adhesive biomedical applications. Snail shell wastes were sourced and processed to obtain (HAp) particles of ˂20 μm. The bio-derived hydroxyapatite-based epoxy composites were produced using the stir-cast method by mixing the hydroxyapatite with the epoxy resin and hardener before pouring into the moulds where they are allowed to cure. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) of the snail shell hydroxyapatite particles were carried out while mechanical, wear, and physical properties of the developed composites were evaluated. SEM images of the fracture surfaces were also examined. The results showed that enhancements occurred from the addition of snail shell-derived HAp to epoxy resin in the developed composites. The results revealed that most of the properties gave their optimum values when 15 wt.% reinforcement was used. At this weight fraction, optimum values were obtained which include 43 MPa for maximum flexural strength, 40HS for hardness, 40 J for impact, 0.35 W/mK for thermal conductivity, and 0.07 for wear index

Modern trends in recycling waste thermoplastics and their prospective applications: a review

Thermoplastics and thermosetting plastics are two major classes of polymers in that have recently become materials that are indispensable for humankind. Regarding the three basic needs of human beings—food, shelter, and clothing—polymers and polymer-based materials have gained pre-eminence. Polymers are used in food production, beginning with farming applications, and in the health sector for the development of various biomaterials, as well as in shelter and clothing for a variety of applications. Polymers are the material of choice for all modern-day applications (transportation, sporting, military/defence, electronics, packaging, and many more). Their widespread applications have created many negative challenges, mainly in the area of environmental pollution. While thermoplastics can be easily reprocessed to obtain new products, thermosetting plastics cannot; thus, this review focuses more on the use of waste from thermoplastics with less emphasis on thermosetting plastics. Hence, the review presents a concise summary of the availability of waste thermoplastics as raw materials for product development and the anticipated benefits. The prospects for waste thermoplastics and thermosetting plastics, the possibility of cleaning the environment, and the uncovering of opportunities for further research and development are presented. The limitations of the current methods of waste polymer recycling are highlighted with possible future prospects from newly introduced methods. With zero tolerance for polymer waste in our environments, potential uses for recycled thermosetting plastics are described. Waste polymers should be seen as potential raw materials for research and development as well as major materials for new products. Recycled polymers are expected to be processed for use in advanced materials applications in the future due to their availability. This review shows that the major source of environmental pollution from polymers is the packaging, hence the need to modify products for these applications by ensuring that most of them are biodegradable

Abrasion Resistance and Water Absorption Characteristics of Ti-HAp Hybrid Reinforced Polyetheretherketone Biocomposites

The influence of abrasion on biomedical implant in human body is a constant cause of pain, discomfort and sometimes a repeat of surgery as a result of the complications from the effects of wear on the implants and the negative consequences of the resultant abrasive particles on the surrounding tissue and bodily environment. To alleviate this, a titanium-hydroxyapatite hybrid reinforced polyetheretherketone (PEEK) biocomposite material was developed, characterized and tested. X-Ray Diffraction characterization revealed that the calcined eggshell was composed mainly of lime and portlandite. The calcined eggshell was then used in the synthesis of hydroxyapatite powder (HAp) with characteristic bands confirmed by FTIR spectroscopic analysis. Biocomposites were developed from the blend of titanium and hydroxyapatite powders in varying proportions as reinforcements in PEEK matrix. The developed composites and control sample were subjected to abrasion and water absorption tests from where it was revealed that biocomposite sample reinforced with 10 wt.% orthophosphoric acid synthesized eggshell possess optimum abrasion resistance with a wear index of 0.20 mg/cycle with an acceptable level of water absorption next to the unreinforced polyetheretherketone over a period of 35 days