AFM fracture surface study of vinylester and unsaturated polyester based thermosets

MOSIEWICKI, MIRNA A.; SCHROEDER, WALTER F.; LEITE, FABIO; HERMANN, PAULO; DA SILVA CURVELO, ANTONIO; ARANGUREN, MIRTA I.; BORRAJO, JULIO

JOURNAL OF MATERIALS SCIENCE

Springer

Lugar: Massachusetts; Año: 2006 vol. 41 p. 6154 - 6158

0022-2461

In the present work the relationship between the final morphologies of styrene/vinylester (St/VE) and styrene/unsaturated polyester (St/UP) cross-linked thermosets and the St-resin initial ratio is analyzed, and the development of the microstructures resulting from the use of the two different unsaturated resins is compared. Different final materials were prepared varying St:resin ratio in a wide concentration range. The high stiffness of these materials allows obtaining fragile fracture surfaces like mirror al room temperature. The investigation of the final microstructures of these materials by atomic force microscopy (AFM) reveals structures to nanometric scale that could not be observed by scanning electron microscopy (SEM). Both St/VE and St/UP systems present nodular type morphologies although the differences in the VE and UP molecular structures. Depending on the concentration of St monomer in the initial mixture, the morphologies of the reacted resins are clearly different. These differences are explained using models suggested for these systems.