Degradation and stabilisation of styrene-ethylene-butadiene-styrene (SEBS) block copolymer

The degradation of hydrogenated poly[styrene-b-butadiene-b-styrene] or poly[styrene-b-(ethylene-co-butylene)-b-styrene], (SEBS) has been studied using a variety of analytical and spectroscopic methods including thermal analysis, UV, luminescence and FTIR spectroscopy coupled with crosslinking and hy...

Full description

Saved in:
Bibliographic Details
Published in:Polymer degradation and stability 2001, Vol.71 (1), p.113-122
Main Authors: ALIEN, Norman S, EDGE, Michele, WILKINSON, Arthur, LIAUW, Cristopher M, MOURELATOU, Despina, BARRIO, Juan, MARTINEZ-ZAPORTA, Maria A
Format: Article
Language:English
Subjects:
Applied sciences
Chemical reactions and properties
Degradation
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The degradation of hydrogenated poly[styrene-b-butadiene-b-styrene] or poly[styrene-b-(ethylene-co-butylene)-b-styrene], (SEBS) has been studied using a variety of analytical and spectroscopic methods including thermal analysis, UV, luminescence and FTIR spectroscopy coupled with crosslinking and hydroperoxide analysis in order to understand the nature of the processes involved. High temperature oxidation of non-commercial unstabilised material results in chain scission and severe crosslinking giving rise to extensive discolouration. FTIR analysis shows complex degradation processes with distinct features associated with each phase. There is a solvent soluble clear phase showing oxidation due primarily to the aliphatic part with a predominant absorption associated with terminal carboxylic acid groups at 1713 cm exp -1 . Anhydrides and alpha , beta -unsaturated carbonyl species are also formed in this matrix. There is also a solvent insoluble phase, which is predominantly crosslinked aliphatic material due to the formation of hydroperoxides and peracids/peresters. Vinyl groups are also evident in this phase. Thus, end group oxidation is a predominant process with the immediate autocatalytic formation of high concentrations of primary hydroperoxides during the early stages of oxidation. These species are unstable and breakdown rapidly leaving a steady-state concentration of more stable hydroperoxides. The luminescence also shows a rapid initial disruption of the polystyrene excimers coupled with the formation of long wavelength milting polyconjugated chromophores, possibly, stilbene type in nature. Colour is evident is both crosslinked and uncrosslinked phases.
ISSN:0141-3910
1873-2321