Recent studies on the kinetics of phase separation in hybrids acrylic polyurethanes

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

Activity Report 2007 - Brazilian Synchrotron Light Laboratory

Editora Cubo

Año: 2008 p. 1 - 2

1518-0204

Acrylic/polyurethane or polyurethane/acrylate hybrids materials are an interesting class of materials that combine filmforming properties of polyurethanes (PUs) and the low prices of acrylics (ACs). The presence of a chemical linkage between the PU and the acrylics restricts the phase segregation of both polymers to the nanoscale. However, the amount of incorporation of acrylic into a PU matrix is limited and, for high acrylic contents, multiphase segregation can occurs and a domain of pure acrylic polymer is formed. As observed in previous work  films formed from dispersions with a 90 wt:% of acrylic are phase separated. In addition, by annealing samples with 70 wt:% of acrylic content at 6°C for 48h, a greater tendency to form separated phases was observed. In a previous project we tried to follow the structural changes occurring during the annealing by SAXS and WAXS techniques using in-situ thermal treatment, but the results of experiments did not allow following the phase segregation. In view of those results we have performed, under the proposal D11A-SAXS 5701/06, additional measurements using the SAXS2 beamline, on previously cured samples in the laboratory at different times. The results of these experiments are the subject of the present report.