Abstract
The aim of this study was to test the hypothesis that microwave post-polymerization treatment influences the rise of hardness, flexural strength, impact strength and fracture toughness of autopolimerizing poly(methyl-methacrylate) by the decrease in residual monomer content. Specimens produced from a commercial acrylic denture reline resin were polymerized according to manufacturers instructions. Control group was left untreated, while other five were post irradiated in a microwave oven with different power and time settings, keeping the irradiation energy constant. Each group of samples was tested for mentioned mechanical properties. Enthalpies of polymerization were tested by differential scanning calorimetry (DSC), while the amount of residual monomer was determined using fourier transform infra-red spectroscopy (FTIR). Microwave post-irradiation resulted in increase of all tested mechanical properties. The highest mecanical properties were obtained with maximum irradiation power, which was confirmed by the results of ANOVA statistical analysis. It has been found that residual monomer content strongly influences the benefits in all tested mechanical properties, increasing biocompatibility. These results have been confirmed by the results of Scanning electron microscope (SEM) fracture surface analisys. Keywords: PMMA biopolymer, microwave post – irradiation, mechanical properties, residual monomer