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Objective The aim of the present study was to evaluate the mechanical and thermal characteristics of two denture base acrylic resins containing silver nanoparticles (AgNPs).Material and Methods Two different acrylic denture base resins (heat-polymerized and microwave polymerized) containing 0.3, 0.8 and 1.6 wt% AgNPs were evaluated for flexural strength, elastic modulus and impact strength. The glass transition temperature (Tg) and relative heat capacity (Cp) of the samples were determined from the Differential Scanning Calorimetry (DSC) results. For statistical analysis, two-way ANOVA and Tukey-HSD tests were performed.Results Addition of 0.8% and 1.6% AgNPs in microwave-polymerized resin significantly decreased the transverse strength and elastic modulus. In terms of impact strength, the addition of AgNPs has no effect on both resin groups. Glass transition temperature (Tg) was decreased with the addition of AgNPs for both denture base resins.Conclusions The incorporation of AgNPs, generally used for antimicrobial efficiency, affected the transverse strength of the denture base acrylic resins depending on the concentration of nanoparticles. Tg was decreased with the addition of AgNPs for both denture base resins.

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In this study, mechanical, thermal and rheological properties of vulcanised ethylene propylene diene monomer (EPDM) rubber containing different amounts of vulcanising agent, filler, paraffinic oil and stearic acid were compared. Moreover, reaction rate constant of the curing reaction has been calculated from the results of the rheological tests, and relative change of rate constant with the change of additives was studied by a new method. Thermal gravimetric analysis with in situ Fourier transform infrared (FTIR) spectra was taken, and the thermal degradation of the EPDM rubber was observed for varying amounts of vulcanising agent and filler content. Although the vulcanising agent improved the mechanical properties of the EPDM initially, a further increase in the vulcanising agents deteriorated the mechanical properties. Attenuated total reflectance FTIR spectrum confirmed the decrease in the relative degree of cross-linking with the increase in the vulcanising agent content to 10 h 21 . Moreover, attenuated total reflectance FTIR spectra reaffirmed that cross-linking density increases with carbon black content. In situ FTIR spectra showed that the thermo-oxidative stability increased with the increase in filler content.