Relation between structure and diisocyanate type in polyurethanes and acrylic/polyurethane hybrids studied by SAXS, WAXS and FTIR

PERUZZO, P.J.; PARDINI, O.R.; AMALVY, J.I.

Campinas

Congreso; 17ª. RAU Reunión Anual de Usuarios LNLS; 2007

Laboratorio Nacional de Luz Sincrotron - Brasil

Polyurethane elastomers are an interesting class of materials that typically consist of semi-crystalline hard segments and amorphous polyether soft segments. It is well known that the particular chemical structure of polyurethanes is reflected in both their morphology and fundamental properties. Due to the distinct chemical incompatibility of soft and hard segments, a phase separation occurs in segmented urethanes, and as a consequence a specific domain structure is formed. These segments are thermodynamically incompatible with the result that the materials are strongly microphase-separated at normal conditions. Polyurethanes are prepared using diisocyanates and polyol and the structure in the solid phase depends on the type of diisocyanate. In this work two polyurethanes prepared using isophorone diisocyanate (IPDI) and m-tetramethylxylene diisocyanate (TXMDI) have been investigated. SAXS was utilized to evaluate the presence of microphase separation and WAXS to explore the ordering of the hard domains. Morphology modification by including an acrylic component and by thermal curing is also investigated for both systems. FTIR experiments have also been carried out to correlate with structural changes observed in SAXS.