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Commercial poly methyl methacrylate (PMMA)-based cement is currently used in the field of orthopedics. However, it suffers from lack of bioactivity, mechanical weakness, and monomer toxicity. In this study, a PMMA-based cement nanocomposite reinforced with hydroxyapatite (HA) nanofibers and two-dimensional (2D) magnesium phosphate MgP nanosheets was synthesized and optimized in terms of mechanical property and cytocompatibility. The HA nanofibers and the MgP nanosheets were synthesized using a hydrothermal homogeneous precipitation method and tuning the crystallization of the sodium-magnesium-phosphate ternary system, respectively. Compressive strength and MTT assay tests were conducted to evaluate the mechanical property and the cytocompatibility of the PMMA-HA-MgP nanocomposites prepared at different ratios of HA and MgP. To optimize the developed nanocomposites, the standard response surface methodology (RSM) design known as the central composite design (CCD) was employed. Two regression models generated by CCD were analyzed and compared with the experimental results, and good agreement was observed. Statistical analysis revealed the significance of both factors, namely, the HA nanofibers and the MgP nanosheets, in improving the compressive strength and cell viability of the PMMA-MgP-HA nanocomposite. Finally, it was demonstrated that the HA nanofibers of 7.5% wt and the MgP nanosheets of 6.12% wt result in the PMMA-HA-MgP nanocomposite with the optimum compressive strength and cell viability. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) are in demand for electrical insulation and thermal management applications; however, their low mechanical and thermal properties pose major challenges. Herein, we report on novel properties of PE-boron nitride (BN) nanocomposites prepared by melt compounding followed by injection molding. The thermal and mechanical properties of silane-functionalized (sBN) and non-functionalized (pBN) PE-BN nanocomposites were studied in order to assess the role of silane functional groups at the interface of BN nanosheets and PE matrix. In comparison with PE materials, addition of 5 wt % BN nanosheets increases tensile modulus of elasticity by 37 and 42%, flexural modulus of elasticity by 24 and 30%, tensile strength by 15 and 27%, and storage modulus by 80 and 91% for pBN and sBN nanocomposites, respectively. Besides mechanical reinforcement, thermal and thermomechanical properties were evaluated for PE-BN nanocomposites. While thermal stability of PE-pBN and PE-sBN nanocomposites was comparable, coefficient of thermal expansion was decreased by 12 and 20% at 5 wt % pBN and sBN nanosheets, respectively. These polymer nanocomposites with enhanced mechanical and thermal properties can be an excellent choice for application in insulation materials, including thermal interface layers in electronic devices. Image 1 [ABSTRACT FROM AUTHOR]