Time-temperature and time-stress correspondence in nonlinear creep. Experimental behaviour of amorphous polymers and quantitative modelling approaches

resumo

Non-linear creep is described by a non-simulative, analytical, dynamic molecular modelling approach. Elementary, molecular-scale, process-relevant frequencies are derived by adequate kinetic formulation. They follow almost exactly an Arrhenius-like behaviour with a range of activation enthalpies. Their relative contribution to the overall macroscopic behaviour of the materials is quantified to account for the materials' retardation time spectra and final non-Arrhenius behaviour. A new creep compliance equation is derived, yielding a fully coupled time-temperature-stress formulation, with long-term predictive capability. Experimental data for poly(methyl methacrylate) are analysed to identify the extent to which time-temperature and the time-stress correspondence relationships may be valid, and it is shown that they are approximations (especially the latter), limited to narrow ranges of experimental variables, in contrast to the proposed model, which more reasonably fits the experimental behaviour.

palavras-chave

SHORT-TERM TESTS; SHIFT FACTOR; SERVICE PERFORMANCE; RELAXATION; PREDICTION; POLYETHYLENE; ORIENTATION; EQUATION; TENSILE

categoria

Polymer Science

autores

Andre, JRS; Pinto, JJCC

Grupos

Partilhe este projeto

Publicações similares

Usamos cookies para atividades de marketing e para lhe oferecer uma melhor experiência de navegação. Ao clicar em “Aceitar Cookies” você concorda com nossa política de cookies. Leia sobre como usamos cookies clicando em "Política de Privacidade e Cookies".