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Molecular orientation in novolac cured epoxy resins as studied by rheo‐optical FTIR spectroscopy
Author(s) -
Scherzer Tom
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(19981010)70:2<247::aid-app5>3.0.co;2-u
Subject(s) - diglycidyl ether , epoxy , materials science , glass transition , fourier transform infrared spectroscopy , composite material , relaxation (psychology) , polymer chemistry , deformation (meteorology) , elongation , annealing (glass) , polymer , bisphenol a , chemical engineering , ultimate tensile strength , psychology , social psychology , engineering
The molecular orientation and relaxation behavior was studied by rheooptical FTIR spectroscopy during the uniaxial deformation of epoxy resins prepared from the diglycidyl ether of butanediol and novolacs on the basis of bisphenol A. The investigation of orientation phenomena was performed in both the rubbery and the glassy state of the epoxies. Results are discussed with regard to the respective mechanism of deformation. Moreover, the effect of temperature, strain rate, and the molecular weight of the novolacs used on the orientation behavior and the mechanical properties was studied. A significant influence of these parameters on the molecular deformation behavior was observed. The reversibility of the orientation at temperatures above and below the glass transition temperature was examined. Epoxy films were subjected to successive loading–unloading cycles including elongation, relaxation, and annealing. The investigations show that the orientation is completely reversible in the rubbery state, but it is only partly reversible below the glass temperature. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 247–259, 1998