Propriedades mecânicas e superficiais de resina acrílica termopolimerizável incorporadas com nanopartículas de montmorilonita pura e montmorilonita silanizada

Abstract

Objective: To evaluate the mechanical and surface properties of polymethylmethacrylate (PMMA) thermopolymerizable acrylic resin incorporated with silanized montmorillonite (MMT) nanoparticles and pure montmorillonite. Methodology: One hundred and five mini bars of dimensions (10 x 2 x 2 mm) and 84 blocks dimensions (5 x 5 x 2 mm) were made, divided into groups according to the factors " material” (Control, pure Montmorillonite and Silanized Montmorillonite) and "percentage" by mass (0.5%, 1.0% and 3.0%), totaling 7 groups for bending (n=15) and roughness (n= 12). The bars were subjected to the three-point mini bending test (2mm/min, 50kgf) and the blocks were subjected to surface roughness analysis. One sample from each group was selected for topographic analysis in Scanning Electron Microscopy (SEM). The data from the mini-bending (MPa) and roughness (µm) tests were analyzed using ANOVA and Tukey (5%). Results: In the flexural strength test, different percentages of montmorillonite addition had a negative influence on the result (p<0.0001). It was noted that with the addition of pure MMT at 0.5% and 1.0%, there was a significant decrease in strength. For roughness, ANOVA (p = 0.001) showed that there was a significant difference between the groups. The TUKEY test indicated that the average roughness of the 0.5% montmorillonite group (0.73±0.13) was superior to the control (0.35±0.10). In the topographic analysis, through SEM, the surfaces of the groups with the addition of silanized montmorillonite were more homogeneous, with more distributed particles. Conclusion: The different percentages of pure montmorillonite had a negative influence on the acrylic resin properties. roughness was altered in most groups; and specimens containing silanized MMT showed better particle scattering under resin surfaces.

Keywords: Acrylic resin. Flexural strength. Montmorillonite. PMMA. Roughness. Objective: To evaluate the mechanical and surface properties of polymethylmethacrylate (PMMA) thermopolymerizable acrylic resin incorporated with silanized montmorillonite (MMT) nanoparticles and pure montmorillonite. Methodology: One hundred and five mini bars of dimensions (10 x 2 x 2 mm) and 84 blocks dimensions (5 x 5 x 2 mm) were made, divided into groups according to the factors " material” (Control, pure Montmorillonite and Silanized Montmorillonite) and "percentage" by mass (0.5%, 1.0% and 3.0%), totaling 7 groups for bending (n=15) and roughness (n= 12). The bars were subjected to the three-point mini bending test (2mm/min, 50kgf) and the blocks were subjected to surface roughness analysis. One sample from each group was selected for topographic analysis in Scanning Electron Microscopy (SEM). The data from the mini-bending (MPa) and roughness (µm) tests were analyzed using ANOVA and Tukey (5%). Results: In the flexural strength test, different percentages of montmorillonite addition had a negative influence on the result (p<0.0001). It was noted that with the addition of pure MMT at 0.5% and 1.0%, there was a significant decrease in strength. For roughness, ANOVA (p = 0.001) showed that there was a significant difference between the groups. The TUKEY test indicated that the average roughness of the 0.5% montmorillonite group (0.73±0.13) was superior to the control (0.35±0.10). In the topographic analysis, through SEM, the surfaces of the groups with the addition of silanized montmorillonite were more homogeneous, with more distributed particles. Conclusion: The different percentages of pure montmorillonite had a negative influence on the acrylic resin properties. roughness was altered in most groups; and specimens containing silanized MMT showed better particle scattering under resin surfaces.