Síntese e Caracterização de elastômeros microcelulares de poliuretano

Abstract

In this work, three different microcellular polyurethanes elastomers (EMPU) based on 4,4-diphenylmethane diisocyanate (MDI) with different rigid phase contents were prepared (Formulations 1, 2 and 3 with 32, 35 and 42% of rigid phase content, respectively). The EMPU were obtained by two steps method. The samples were evaluated with respect to physical, mechanical, morphological, thermal and chemical properties. The results showed that the formulation with higher rigid phase content has higher tensile and tear strength. The deformation at rupture not show significant variation with the change in the rigid phase content. Micrographs of SEM indicated that the higher rigid phase content promoted the best cells homogeneity in the samples. The termogravimetric analysis show the presence of the two degradation steps associated to the rigid and flexible phase, respectively. Diferential scanning calorimetry indicated that the EMPU has a phase separation at room temperature. The increase in the rigid phase content implicated in the increase of the cross-linked density of the material. Finally, the EMPU have good chemical resistence in comumm solvents.