Premium
Photodegradation of poly[ethylene‐ co ‐propene‐ co ‐(5‐ethylidene‐2‐norbornene)] rubbers, 2. Physical and dynamic‐mechanical behaviour under accelerated conditions
Author(s) -
Scoponi Marco,
Pradella Fiorella,
Carassiti Vittorio,
Tartari Davide
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950316
Subject(s) - norbornene , natural rubber , propene , ultimate tensile strength , polymer chemistry , dynamic mechanical analysis , ethylene , materials science , glass transition , elastomer , elongation , chemistry , chemical engineering , polymer , composite material , copolymer , organic chemistry , catalysis , engineering
The physical and dynamic‐mechanical behaviour during the photo‐oxidation under accelerated conditons of three poly(ethylene‐ co ‐propene‐ co ‐5‐ethylidene‐2‐norbornene) (EPDM) rubbers with different contents of 5‐ethylidene‐2‐norbornene System. name: 5‐ethylidenebicyclo[2.2.1]hept‐2‐ene. (ENB) are reported. These results show the dependence of the glass transition temperature both on the ENB content and on the photo‐oxidation time in accordance with network formation in the rubber matrix under accelerated conditions. The tensile experiments also show an increase of the elastic modulus as function both of ENB content and of photo‐oxidation time. The Murayama and Mooney‐Rivlin equations are applied to estimate the average molecular weight between two crosslinking nodes occurring in the rubber matrix during photo‐oxidation with tensile and dynamic‐mechanical experiments, respectively. Some correlations of physical and dynamic‐mechanical changes with the proposed mechanism of photo‐oxidation, due to the formation and reactivity of unsaturated groups, show that the crosslinking processes prevail over chain scissions.