INVESTIGADORES
FRONTINI patricia Maria
artículos
Título:
Elastic modulus and yield stress of epoxy networks in the glassy state
Autor/es:
C. VALLO; P. M. FRONTINI,; .R. WILLIAMS
Revista:
Polymer Gels and Networks
Editorial:
Elsevier
Referencias:
Año: 1993 p. 257 - 266
ISSN:
0966-7822
Resumen:
Elastic modulus (E) and yield stress in uniaxial compression (σy) were determined for a series of epoxy-amine networks prepared with different stoichiometric ratios. Tests were performed at room temperature, i.e. in the glassy state of the polymeric networks. Observed trends were analysed and compared with literature results. The following conclusions were obtained. (i) E depends both on packing density (ϱ∗) and sub-vitreous relaxations (Tβ) that are active at the testing conditions, but the (ϱ∗) is the predominant factor when it varies significantly in the particular series, i.e. Δϱ∗ ∼ 10−2. (ii) The sstress at the post-yield plateau (in uniaxial compression) may be correlated with the crosslink density of the epoxy network. (iii) There is no general relationship between E and σy as is frequently stated (Brown's rule).