Síntese, caracterização e polimerização de bis(metacrilamida)s

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2011

RESUMO

The aim of this study was the synthesis, characterization and investigation of kinetic behavior of photo- and thermal polymerization of 4,4-diphenylmethane-bis(methacrylamide) (BisFenil), N,N¿,hexamethylene-bis(methacrylamide) (BisHexa), N,N¿-decamethylene-bis(methacrylamide) (BisDeca) and N,N¿-dodecamethylene-bis(methacrylamide) (BisDodeca). Methacrylates esters commonly used in the formulation of dentin adhesives, Bisphenol-A-Glycidyl-methacrylate (BisGMA), 1,6-hexanediol-bis(methacrylate) (BisHMA), 1,12-dodecanediol-bis(methacrylate) (BisDMA) and 2-Hydroxiethylmethacrylate were used as control in the analysis. The synthesis of bis(methacrylamide) was carried out by nucleophilic substitution reaction of methacryloyl chloride with different diamines. The monomers were purified by recrystallization in acetonitrile or hexane and characterized by infrared (IR) and nuclear magnetic resonance (1H NMR). The activation energies (Ea) of thermal polymerization of bis(methacrylamide)s and methacrylates were determined by Differential Scanning Calorimetry (DSC). The monomer BisFenil was dissolved in 2-hydroxiethylacrylamide (HEAM) at concentrations of 0, 5, 7 and 8% wt%, respectively. As control group (GC) was used BisGMA/HEMA (2:1). The groups were submitted to DSC analysis coupled with a Photocalorimetry Accessory (PCA), resistance to bending, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Other bis(methacrylamide)s were investigated by DMA and TGA in HEAM at the concentration of 8 wt%. Amides, in most cases, showed higher Ea than esters (BisHMA=23,658x103kJ.mol-1, BisHexa=18,578x103kJ.mol-1, BisDMA= 39,212x103kJ.mol-1 e BisDodeca=33,609x103kJ.mol-1). The occurence of the crosslinking was evident in the viscoelatic behavior and mass loss of the experimental groups. The values of the modulus of elasticity was analyzed by one-way ANOVA and Tukeys test (p<0,005), and the values of flexural strength by Krukal-Wallis analysis with complementary method of Dunn (p<0,05). The bis(methacrylamide)s show higher degree of conversion than esters, and similar mechanical properties, however further investigation is necessary for their effective application in dentistry.

ASSUNTO(S)

metacrilamida calorimetria polimerizacao

ACESSO AO ARTIGO

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