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Characterization of fluoroelastomer networks: II. SEC, FTIR, and ODR analysis
Author(s) -
Theodore A. N.,
Zinbo M.,
Carter R. O.
Publication year - 1996
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(19960919)61:12<2065::aid-app3>3.0.co;2-8
Subject(s) - degree of unsaturation , curing (chemistry) , fourier transform infrared spectroscopy , solvent , materials science , double bond , polymer chemistry , infrared spectroscopy , nucleophile , infrared , absorption (acoustics) , chemical engineering , chemistry , composite material , organic chemistry , optics , catalysis , engineering , physics
The role of an accelerator in the nucleophilic cure of fluorocarbon compounds was further examined by preparing materials without a crosslinker. Under the previously used curing conditions, ODR reveals the formation of a secondary, accelerator‐induced network that is unstable at slightly higher temperature, i.e., ≥190°C. Increased crosslink density and color are observed with the cure time, indicating slow curing reactions and likely formation of conjugated unsaturation. SEC of selective solvent‐soluble fractions derived from specimens obtained from the key cure stages shows initially a falling refractive‐index response. However, this change is followed by a shift in MWDs toward lower average molecular weights. On the other hand, infrared examination shows a continuous increase in the 1718 cm −1 absorption, but no major presence for the 1680 cm −1 absorption seen in the previous study in the presence of a crosslinker. The concurrent increase in the 3114 cm −1 peak confirms the presence of a CFCH double bond. The solvent‐soluble portions and bulk specimens have very similar infrared features. © 1996 John Wiley & Sons, Inc.