الفهرس 
الغلافيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
This work presents the results of the experimental investigation on the tribological behavior of PMMA reinforced by silica and zirconia nanoparticles for dentures. Two methods were used to cure the test specimens, the first was heat cured method and the second was cold cured one. Unfilled heat cured PMMA, unfilled cold cured PMMA and four groups of specimens composites were prepared and investigated. For heat cure method, unfilled PMMA and two groups of specimen composites were prepared. The first group was PMMA composites reinforced with 2.5, 5, 7.5, 10, 12.5 and 15 wt. % of SiO2 nanoparticles. The optimum composition that gives the excellent tribological properties was determined. To more improve the wear resistance for optimum composition of the first group, the second group was prepared by adding different weight contents of zirconia (ZrO2) nanoparticles, 2.5, 5 and 7.5 wt. % to the optimum composite from the first group. The optimum weight content to get the minimum wear value for PMMA/SiO2 and ZrO2 nanoparticles composites was determined. For cold cure method, unfilled PMMA and another two groups of specimen composites with the same weight percentages of SiO2 and ZrO2 nanoparticles were prepared. The effect of reinforcing PMMA with silica and zirconia nanoparticles on the wear and friction coefficient was investigated under dry sliding conditions, constant sliding velocity and different applied normal load values ranging from 5 to 25 N. For heat cured method, the optimum values of weight percentages for both PMMA/SiO2 composites and PMMA/SiO2 and ZrO2 composites with respect to the minimum value of wear were obtained. For cold cured method, the optimum content of PMMA/SiO2 composites was determined while adding ZrO2 nanoparticles to the optimum composite of PMMA/SiO2 had no more improvement on the wear resistance.