Modificação do poli (metacrilato de metila) com poli (epicloridrina-co-oxido de etileno)

AUTOR(ES)

Sandra Maria Rocha

DATA DE PUBLICAÇÃO

2000

RESUMO

The modification of poly(methyl methacrylate) (PMMA) with poly(epichlorohydrin-co-ethylene oxide) [(P(EPI-co-EO)] is conducted with the polymerization of the methyl methacrylate in the presence of the elastomer. With this purpose, mixtures containing 0, 10, 20, 30 and 40 wt% of the elastomer, benzoyl peroxide as the initiator, and ethylene glycol dimethacrylate (EGDMA), as the crosslinking agent for PMMA, in the proportions of 0, 1, 3 and 5 wt% in relation of the MMA weight are polymerized at 60°C for 96 h. The miscibility of the mixtures is evaluated by dynamical-mechanical analysis (DMA) and for all compositions a broadening of the glass transition is observed. This profile is attributed to the formation of microregions with distinct compositions and crosslinking densities. The network was characterized by swelling experiments and DMA, as well. Those methods yielded information on the heterogeneity of composition and crosslinking densities of the mixtures. They also provided evidences on a possible graft polymerization between the elastomer and the PMMA and the elastomer participation as a crosslinker. There are also evidences, that the graft copolymerization between the elastomer and PMMA take a place during the network formation and that the elastomer participate as co-crosslinker for the PMMA. The kinetics of the network was followed by DSC and the reaction enthalpy, the conversion, and the activation energy were evaluated. These experiments were carried out in the dynamical and isothermal modes. This study showed that the elastomer not only participates in the MMA polymerization forming a grafting copolymer but also influences in a complex way, the cure kinetics. Flexural tests using microsamples showed that mixtures of the same composition, but with distinct crosslinking densities and network formation showed a behavior varying from tough to rigid.

ASSUNTO(S)

redes de polimeros polimerização

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