Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate
Autor(a) principal: | |
---|---|
Data de Publicação: | 2013 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10314/2502 |
Resumo: | Sound models of temperature- and strain-dependent non-linear stress relaxation are still lacking. Very recent work has shown that focusing on polymers’ local, non-affine, strains and stresses provides an adequate basis for developing such models and accurately predicting experimental stress relaxation moduli, the values of meaningful physical parameters and long time behavior, from experiments spanning only a few hours. A new modeling strategy that explicitly considers such non-affine local stresses and strains was applied to two amorphous polymers – a poly(methylmethacrylate), PMMA, and a bisphenol-A polycarbonate, PC. The results support a view of the stress relaxation process where a temperature-dependent, truncated, approximately log-normal distribution of local cooperative (or clustering) transitions are involved, at and above a minimum (or primitive) relaxor size. Within this view, cooperativity (via the average and maximum cluster sizes) increases with decreasing temperatures. Beyond the reasonable agreement with the experiments, the model succeeds in predicting (1) the effect of increases in the fully relaxed modulus, E∞, as in semi-crystalline or strongly cross-linked polymers, (2) the strict inapplicability of time-temperature and strain-time super-positions, (3) an extended, Kohlrausch-Williams-Watts, type of relaxation response, spanning 12 or more time decades, and (4) specific, meaningful, physical parameters: a minimum activation energy (close to those of corresponding β-type transitions), the (occupied + free) volume of the primitive relaxor, and the approximate crossover temperature, Tc, and frequency, νc, both of critical importance in condensed matter dynamics. The model also has the potential of incorporating the effect of changes in free volume and allows very fast computations, irrespective of the experimental time scale. |
id |
RCAP_74241811f6f4dc6b22bc53416f9c361d |
---|---|
oai_identifier_str |
oai:bdigital.ipg.pt:10314/2502 |
network_acronym_str |
RCAP |
network_name_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository_id_str |
7160 |
spelling |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonateSound models of temperature- and strain-dependent non-linear stress relaxation are still lacking. Very recent work has shown that focusing on polymers’ local, non-affine, strains and stresses provides an adequate basis for developing such models and accurately predicting experimental stress relaxation moduli, the values of meaningful physical parameters and long time behavior, from experiments spanning only a few hours. A new modeling strategy that explicitly considers such non-affine local stresses and strains was applied to two amorphous polymers – a poly(methylmethacrylate), PMMA, and a bisphenol-A polycarbonate, PC. The results support a view of the stress relaxation process where a temperature-dependent, truncated, approximately log-normal distribution of local cooperative (or clustering) transitions are involved, at and above a minimum (or primitive) relaxor size. Within this view, cooperativity (via the average and maximum cluster sizes) increases with decreasing temperatures. Beyond the reasonable agreement with the experiments, the model succeeds in predicting (1) the effect of increases in the fully relaxed modulus, E∞, as in semi-crystalline or strongly cross-linked polymers, (2) the strict inapplicability of time-temperature and strain-time super-positions, (3) an extended, Kohlrausch-Williams-Watts, type of relaxation response, spanning 12 or more time decades, and (4) specific, meaningful, physical parameters: a minimum activation energy (close to those of corresponding β-type transitions), the (occupied + free) volume of the primitive relaxor, and the approximate crossover temperature, Tc, and frequency, νc, both of critical importance in condensed matter dynamics. The model also has the potential of incorporating the effect of changes in free volume and allows very fast computations, irrespective of the experimental time scale.2016-07-27T20:28:58Z2016-07-272013-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10314/2502http://hdl.handle.net/10314/2502engAndré, José ReinasPinto, Joséinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-01-14T02:55:27Zoai:bdigital.ipg.pt:10314/2502Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T01:42:04.811855Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
title |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
spellingShingle |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate André, José Reinas |
title_short |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
title_full |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
title_fullStr |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
title_full_unstemmed |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
title_sort |
Advanced modeling of polymer non-linear stress relaxation – Poly(methylmethacrylate) and polycarbonate |
author |
André, José Reinas |
author_facet |
André, José Reinas Pinto, José |
author_role |
author |
author2 |
Pinto, José |
author2_role |
author |
dc.contributor.author.fl_str_mv |
André, José Reinas Pinto, José |
description |
Sound models of temperature- and strain-dependent non-linear stress relaxation are still lacking. Very recent work has shown that focusing on polymers’ local, non-affine, strains and stresses provides an adequate basis for developing such models and accurately predicting experimental stress relaxation moduli, the values of meaningful physical parameters and long time behavior, from experiments spanning only a few hours. A new modeling strategy that explicitly considers such non-affine local stresses and strains was applied to two amorphous polymers – a poly(methylmethacrylate), PMMA, and a bisphenol-A polycarbonate, PC. The results support a view of the stress relaxation process where a temperature-dependent, truncated, approximately log-normal distribution of local cooperative (or clustering) transitions are involved, at and above a minimum (or primitive) relaxor size. Within this view, cooperativity (via the average and maximum cluster sizes) increases with decreasing temperatures. Beyond the reasonable agreement with the experiments, the model succeeds in predicting (1) the effect of increases in the fully relaxed modulus, E∞, as in semi-crystalline or strongly cross-linked polymers, (2) the strict inapplicability of time-temperature and strain-time super-positions, (3) an extended, Kohlrausch-Williams-Watts, type of relaxation response, spanning 12 or more time decades, and (4) specific, meaningful, physical parameters: a minimum activation energy (close to those of corresponding β-type transitions), the (occupied + free) volume of the primitive relaxor, and the approximate crossover temperature, Tc, and frequency, νc, both of critical importance in condensed matter dynamics. The model also has the potential of incorporating the effect of changes in free volume and allows very fast computations, irrespective of the experimental time scale. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-01-01T00:00:00Z 2016-07-27T20:28:58Z 2016-07-27 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10314/2502 http://hdl.handle.net/10314/2502 |
url |
http://hdl.handle.net/10314/2502 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
|
_version_ |
1799136912381837312 |