Melting characteristics of high-density polyethylene (HDPE) mixed with nano-size ceramic fillers (hydroxyl apatite and yttria stabilised zirconia) was analysed using the isochronal heating rate between 10°C min À1 and 80°C min À1 . In this investigation, the kinetics of melting of HDPEceramic composites was analysed using the Avrami equation and the Kissinger model, applied to the Avrami formalism. The magnitude of the apparent energy barrier for the melting of HDPE falls within a range of 12 kJ mol À1 and 22 kJ mol À1 , with a tendency for heterogeneous melting which was determined by characterising the value of Avrami exponent, n found to vary between 1 and 2. The heterogeneous nature of melting was also confirmed using the scanning electron microscopy, from which the evidences for both nano-and micro-scale interactions of HDPE with ceramic fillers (HA and yttria stabilised zirconia) were confirmed on a microscopic scale. Ó 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In this investigation, multi-wall carbon nanotubes (MWCNT) with various percentages (0.6%, 1%, 1.4%, 2%) were combined into   ​and High-density polyethylene HDPE (60) wt. % and hydroxyapatite (40) wt. % to form biocomposite using hot-press techniques. The surface topography by AFM images illustrates differences in the roughness of the sample's surface with different adding percentages of MWCNT. The DSC technique exhibits the effect of adding MWCNT in different percentages with the degree of crystallinity, which its effect on mechanical properties for samples. The in vitro bioactivity was investigated by immersion the samples in Ringer's solution as simulated body fluid (SBF) at (0, 3, 6, 9, 12) days (after immersing). The FE-SEM and EDx image explained the apatite layers formation on the sample's surface after 3 days immersed in Ringer solution. Based on XRD Technique, after immersion days in the Ringer solution, the crystallographic structure of hydroxyapatite is formed, forming the monetite.  ​The enhancement of bioactivity has been shown during the incorporation of MWCNT into HA/HDPE composite. These results exhibited excellent indications of biocompatibility properties with the possibility of making promising biomaterials for making bone substitute applications.

The critical size of bone defects resulting from disease or fractures is a medical problem, usually unable to repair spontaneously by the body's healing mechanisms. Bioceramics are being used for bone tissue regeneration to stimulate the growth of bone cells and guide osseous remodeling. The three most common types of bioceramics used in bone tissue engineering (hydroxyapatite, bioactive glass, and tricalcium phosphate) were selected and studied in vivo animal models, exhibiting favorable bone formation with positive biocompatibility reactions for several animal models. In the study, an extensive review of research was conducted to assess the bone-forming capabilities of scaffolds in bone defects and remodeling in vivo. This review aims to support a large-scale assessment of the capabilities of in vivo studies to generate an optimal regenerative process based on an analysis of the results. In addition to providing an essential reference for the applications of bone tissue engineering, the review will assist in developing novel in vivo investigations.

Bones in the human body are a natural composite material that can be fractured due to impact stress and excessive loads. Human bones become less dense and strong when age increases, thereby they become more susceptible to fracture. The present work aims to study the effect of adding nano-ceramic particles on the mechanical properties to fabricate four types of hybrids of Titanium dioxide (TiO2) and Alumina (Al2O3) reinforced polyetheretherketone (PEEK) biocomposites. The objective of this study is to develop and improve the biomechanical properties of the fabricated biomaterials to withstand the loads of the daily human activities. Modeling and analysis of femur bone biomechanics were implemented by using the SOLIDWORKS 17.0 and the finite element ANSYS 15.0 software programs. The response surface methodology (RSM) technique and the Design Expert 11.0 software program were used to improve and verify the results of biomechanical performance of the fabricated biocomposites. From the current research results, it was deduce that the maximum equivalent (von- Misses) and shear stresses on the modeled femur bone are 120,93 and 60,80 MPa. The tensile for modeling the fabricated 20 vol. % TiO2/5 vol. % Al2O3/PEEK biocomposite material is higher than the one of natural femur bone by 10%. The maximum strain energy and the maximum equivalent elastic strain were reduced by 20% and 26,09 %, respectively. The stress safety factor values increased in 5,81%, and the fatigue life for the fabricated biocomposite is more than 40,43%, when compared with natural femur bone material.

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