Effect of the loading of organomodified clays on the thermal and mechanical properties of a model dental resin

Author(s)

Marina Martins Terrin ^[1] ; Alessandra Leves Poli ^[2] ; Marco Antonio Horn Jr ^[3] ; Miguel Guillermo Neumann ^[4] ; Eder Tadeu Gomes Cavalheiro ^[5] ; Ivo Carlos Correa ^[6] ; Carla Cristina Schmitt ^[7]

Affiliation

^[1] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[2] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[3] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[4] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[5] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[6] Universidade Federal do Rio de Janeiro. Faculdade de Odontologia - Brasil

^[7] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

• Document type: Journal article
• Source: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 19, n. 1, p. 40-44, 2016-02-05.

Abstract

Experimental dental resins composed of triethyleneglycol dimethacrylate, urethane dimethacrylate, ethoxylated bisphenol-A-dimethacrylate and bisphenol A glycidyl methacrylate containing an organoclay as filler were prepared by photopolymerization. The addition of organoclay fillers results in slower polymerization rates (0.59 and 0.24 mol L-1 min-1, for the formulations without and with 15% of organoclay, respectively) and lower degrees of conversion (0.50 and 0.35 for the formulations without and with 15% of organoclay), as determined by photocalorimetry. The influence of the organoclay on the thermal and mechanical properties of the resins was evaluated using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) techniques. The (tan δ) and E´ curves indicate the formation of more rigid materials and the damping curve data indicates more homogeneous materials. An increase of storage modulus, E’, was observed for composites with the higher organoclay filler contents. These effects are due to the higher viscosity of the systems with organoclay, resulting in a lower mobility of the radicals during the propagation step of polymerization, as well as to the scattering of the incident photopolymerizing radiation, which lowers the amount of initiation centres. (AU)

• FAPESP's process: 12/19656-0 - Photoinitiation of polymerization and degradation of polymers multicomponent
• Grantee: Carla Cristina Schmitt Cavalheiro
• Support Opportunities: Regular Research Grants