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Radiation cross‐linking of ethylene vinyl alcohal copolymer functionalized with m ‐isopropenyl‐α,α‐diamethyl benzyl isocyanate
Author(s) -
Ekman Kenneth B.,
Näsman Jan H.
Publication year - 1993
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.1993.070500204
Subject(s) - copolymer , isocyanate , polymer chemistry , surface modification , ethylene , materials science , oxygen permeability , chemistry , polymer , oxygen , polyurethane , organic chemistry , catalysis
An ethylene vinyl alcohal copolymer was functionalized with m ‐isopropenyl‐α,α‐dimethyl benzyl isocyanate using reactive processing in a mixer. The Functionalization introduces pendant unsaturation to the polymer, which allows radiation cross‐linking to gel contents > 70% at radiation doses below 100 kGy. Unfunctionalized ethylene vinyl alcohal copolymer, on the other hand, forms no gel upon irradiation. The functionalization was completed within a few minutes of reactive mixing, which was confirmed with both FTIR and 13 C‐NMR measurments. The oxygen permeability of ethylene vinyl alcohal copolymer increased with increasing degree of functionalization, and irradiation of the samples formed trapped radicals, which act as oxygen scavengers. Consequently no oxygen permeability was detected. However, radical activity was inhibited by annealing the samples at 110°C resulting in a 24% higher oxygen permeability values of the irradiated unfunctionalized samples were approximately 13% lower. Laminates of m ‐isopropenyl‐α,α‐dimethyl benzyl isocyanate functionalized ethylene vinyl alcohal copolymer and m ‐isopropenyl‐α,α‐dimethyl benzyl isocyanate functionalized ethylene vinyl hydroxyethyl methacrylate copolymer acquired improved adhesive strength both at dry and wet conditions as well as at elevated temperatures upon exposure to radiation. © 1993 John Wiley & Sons, Inc.