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Low temperature thermal aging of ethylene vinyl alcohol copolymers
Author(s) -
Apicella A.,
Hopfenberg H. B.,
Piccarolo S.
Publication year - 1982
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760220610
Subject(s) - materials science , differential scanning calorimetry , crystallite , crystallinity , vinyl alcohol , crystallization , copolymer , lamellar structure , polymer chemistry , chemical engineering , polymer , recrystallization (geology) , glass transition , composite material , thermodynamics , physics , engineering , paleontology , biology , metallurgy
The crystallites of semicrystalline polymers formed at low temperatures are subject to partial partial melting and recrystallization resulting in a systematic increase in the size and perfection of the nascent crystallites. Differential scanning calorimetry (DSC) and x‐ray studies suggest that ethylene‐vinyl alcohol copolymers (EVOH), in particular, may undergo these secondary crystallization processes upon storage at temperatures far below T m . DSC scans have been run on “as received” and quenched samples; the mole percent of vinyl alcohol in the copolymers studied was 0, 62, 70, 72, 82 and 100 percent. Tests on secondary crystallization kinetics, performed at different temperatures, further confirm the hypothesis of an increased degree of perfection (lamellar thickening) of the bulk crystallites achieved upon long term storage at temperature between T g and T m .