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Necking mechanism and its elimination in uniaxially drawn films of poly(ethylene naphthalate) (PEN)/polyetherimide (PEI) blends
Author(s) -
Cakmak M.,
Kim J. C.
Publication year - 1997
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(19970912)65:11<2059::aid-app1>3.0.co;2-g
Subject(s) - necking , polyetherimide , materials science , glass transition , amorphous solid , composite material , polymer blend , naphthalene , polymer chemistry , polymer , crystallography , copolymer , chemistry , organic chemistry
The influence of blend composition on the deformation behavior of cast amorphous PEN/PEI blends were investigated above their respected glass transition temperatures. PEN inherently shows a sharp necking phenomenon when stretched at temperatures as high as 20°C above its glass transition temperature. This was attributed to highly localized rapid alignment of naphthalene planes parallel to the surface of the films. The addition of PEI was observed to reduce this necking behavior. The neck formation completely disappears when the PEI fraction exceeds 10% in the blend. X‐ray studies indicate that the increase of PEI hinders the rapid alignment of naphthalene planes parallel to the surface of the films. The presence of PEI chains in the blend was found to increase the overall friction between the polymer chains in the system and this was found to prevent the formation of highly localized necks. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2059–2074, 1997