Effect of Low Hydroxyapatite Loading Fraction on the Mechanical and Tribological Characteristics of Poly(Methyl Methacrylate) Nanocomposites for Dentures

Abstract

Denture base materials need appropriate mechanical and tribological characteristics to endure different stresses inside the mouth. This study investigates the properties of poly(methyl methacrylate) (PMMA) reinforced with different low loading fractions (0, 0.2, 0.4, 0.6, and 0.8 wt.%) of hydroxyapatite (HA) nanoparticles. HA nanoparticles with different loading fractions are homogenously dispersed in the epoxy matrix through mechanical mixing. The resulting density, Compressive Young’s modulus, compressive yield strength, ductility, fracture toughness, and hardness were evaluated experimentally; the friction coefficient and wear were estimated by rubbing the PMMA/HA nanocomposites against stainless steel and PMMA counterparts. A finite element model was built to determine the wear layer thickness and the stress distribution along the nanocomposite surfaces during the friction process. In addition, the wear mechanisms were elucidated via scanning electron microscopy. The results indicate that increasing the concentration of HA nanoparticles increases the stiffness, compressive yield strength, toughness, ductility, and hardness of the PMMA nanocomposite. Moreover, tribological tests show that increasing the nanoparticle weight fraction considerably decreases the friction coefficient and wear loss.

Investigation of the Mechanical Behavior of Synthesized Al6061/TiO2 Microcomposites Using an Innovative Stir Casting Method

“…Similar results were concluded by [ 36 , 37 , 38 ]. Furthermore, the enhancement in the hardness of the composite provides evidence for the good distribution of reinforcement particles inside the matrix [ 39 , 40 ].…”

Effect of Nanofillers on Tribological Properties of Polymer Nanocomposites: A Review on Recent Development

“…Some other nanofillers which are less popular, such as a triple system of bio-ceramic, CaTiZrO 5 nanoparticles [ 131 ], nano nano-sized hydroxyapatite (nHA) [ 132 , 133 ], CaCO 3 nanoparticles [ 134 ] and a complex metal alloy, Al 65 Cu 22 Fe 13 quasicrystal (QC) [ 135 ], were incorporated into polymers to improve tribological properties. Interestingly, QC loading of 0.1%, 5% and 10% failed to improve the wear resistance of linear low-density polyethylene (LLDPE) under 147 N applied load.…”

“…Only 1% QC nanoparticles apparently raised the melting point of the nanocomposite, increasing the thermal and wear resistance of the sample. Additionally, due to the formation of a protective antifriction film on the friction surface, 1% QC/LLDPE nanocomposites exhibited a stable COF value when the load was increased to 147 N. It is worth highlighting that a finite element model of a friction test on nHA/PMMA nanocomposites evinced the direct influence of load-bearing capacity of nanocomposites to its tribological performances [ 133 ]. Improved load-bearing capacity with the incorporation of nHA has induced smaller shear stress on the sample surfaces and frictional stress between sliding surfaces.…”

Permeability of a Zinc-Methacrylate-Based Self-Polishing Copolymer for Use in Antifouling Coating Materials by Molecular Dynamics Simulations

“…The densities of Z2 and Z16 increase with increasing water content, which indicates that the H 2 O molecules are well located within the SPCs. The density of the dry and hydrated states of Z16 are higher than those of Z2 because ZMA (1.40 g/cm 3 [40]) is denser than MMA (0.94 g/cm 3 ) [41].…”