Second order elasticity at hypersonic frequencies of reactive polyurethanes as seen by generalized Cauchy relations.
J Phys Condens Matter
; 21(3): 035106, 2009 Jan 21.
Article
en En
| MEDLINE
| ID: mdl-21817265
ABSTRACT
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.
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1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Condens Matter
Asunto de la revista:
BIOFISICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Luxemburgo