Premium
Structural determination of ethylene‐propylene‐diene rubber (EPDM) containing high degree of controlled long‐chain branching
Author(s) -
Mitra Susanta,
Jørgensen Mikkel,
Pedersen Walther Batsberg,
Almdal Kristoffer,
Banerjee Debasish
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.30402
Subject(s) - branching (polymer chemistry) , comonomer , natural rubber , molar mass , epdm rubber , materials science , ethylene propylene rubber , dispersity , polymer chemistry , rheology , diene , viscometer , intrinsic viscosity , composite material , copolymer , viscosity , polymer
This work highlights an attempt to characterize the degree and nature of long‐chain branching (LCB) in an unknown sample of ethylene‐propylene‐diene rubber (EPDM). Two EPDM rubbers selected for this study were comparable in comonomer compositions but significantly different with respect to molar mass and the presence of LCB. Both rubbers contained 5‐ethylidene‐2‐norbornene (ENB) as diene. Solution cast films of pure EPDM samples were used for different characterization techniques. 1 H‐NMR, and 13 C‐NMR were used for assessing the comonomer ratios and LCB. Size exclusion chromatography (SEC) equipped with triple detector system was used to determine the molar mass (both absolute and relative) and polydispersity index (PDI). Presence of branching was also detected using sec‐viscometry. Rheological analysis has also been used for characterizing LCB. Finally, on the basis of the experimental findings and the available theories, an attempt was made to identify the chemical nature and degree of LCB. This study reveals the possibility of detailed characterization of molecular architecture of EPDM containing LCB by comparing with an essentially linear EPDM in light of an existing theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009