[en] The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies—including the generalized Cauchy relation—to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol–gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Disciplines :
Physics Materials science & engineering
Identifiers :
UNILU:UL-ARTICLE-2009-039
Author, co-author :
Philipp, Martine ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Vergnat, Christelle; University of Luxembourg
Müller, Ulrich ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Sanctuary, Roland ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Baller, Jörg ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Possart, Wulff; Fachbereich Werkstoffwissenschaften, Universität des Saarlandes, D-66123 Saarbrücken, Germany
Alnot, Patrick; LPMI, Université Nancy, France
Krüger, Jan-Kristian ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Language :
English
Title :
Second order elasticity at hypersonic frequencies of reactive polyurethanes as seen by generalized Cauchy relations.