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Influence of silica content on migration of antidegradants to the surface in NR vulcanizates
Author(s) -
Choi SungSeen
Publication year - 1998
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/(sici)1097-4628(19980613)68:11<1821::aid-app13>3.0.co;2-x
Subject(s) - wax , natural rubber , polymer chemistry , phenol , chemistry , nuclear chemistry , materials science , organic chemistry
Migration of antidegradants to the surface in silica‐filled natural rubber (NR) vulcanizates was studied with migration‐generating equipment using a vacuum technique. 2,6‐Di‐ t ‐butyl‐4‐methyl phenol (BHT), N ‐phenyl‐ N ′‐isopropyl‐ p ‐phenylenediamine (IPPD), N ‐phenyl‐ N ′‐(1,3‐dimethylbutyl‐ p ‐phenylenediamine (HPPD), and wax ( n ‐C 23 H 48 , n ‐C 24 H 50 , n ‐C 25 H 52 , and n ‐C 26 H 54 ) were employed as antidegradants. The migration rate was found to be dependent on the content of silica in the vulcanizates. IPPD migrates faster than BHT and HPPD irrespective of the content of silica. BHT migrates faster than HPPD at 60 and 80°C, but slower than HPPD at 100°C. The migration rates of BHT, IPPD, and HPPD decrease with increase of the silica content from 30 to 70 phr. Wax with a low molecular weight migrates faster than that with a high molecular weight. The migration rate of n ‐C 23 H 48 , irrespective of migration temperature, decreases with increase of the silica content, similar to BHT, IPPD, and HPPD, but those of n ‐C 25 H 52 and n ‐C 26 H 54 have a local maximum at 50 phr silica content. The activation energies for migration to the surface in the vulcanizate containing 50 phr of silica are 19.3, 28.7, 40.1, 42.2, 51.6, 58.8, and 65.5 kJ/mol for BHT, IPPD, HPPD, n ‐C 23 H 48 , n ‐C 24 H 50 , n ‐C 25 H 52 , and n ‐C 26 H 54 , respectively. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1821–1828, 1998