Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2009-08-01

Journal: POLYMER INTERNATIONAL

Included Journals: Scopus、EI、SCIE

Volume: 58

Issue: 8

Page Number: 912-918

ISSN: 0959-8103

Key Words: epoxy resin; poly(aryl ether ketone); macromolecular curing agent; kinetics

Abstract: BACKGROUND: Reactive thermoplastics have received increasing attention in the field of epoxy resin toughening. This paper presents the first report of using a novel polyaryletherketone bearing one pendant carboxyl group per repeat unit to cure the diglycidyl ether of bisphenol-A epoxy resin (DGEBA). The curing reactions of DGEBA/PEK-L mixtures of various molar ratios and with different catalysts were investigated by means of dynamic differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy methods.
   RESULTS: FTIR results for the DGEBA/PEK-L system before curing and after curing at 135 degrees C for different times demonstrated that the carboxyl groups of PEK-L were indeed involved in the curing reaction to form a crosslinked network, as evidenced by the marked decreased peak intensities of the carboxyl group at 1705 cm(-1) and the epoxy group at 915 cm(-1) as well as the newly emerged strong absorptions of ester bonds at 1721 cm(-1) and hydroxyl groups at 3447 cm(-1). Curing kinetic analysis showed that the value of the activation energy (E(a)) was the highest at the beginning of curing, followed by a decrease with increasing conversion (alpha), which was attributed to the autocatalytic effect of hydroxyls generated in the curing reaction.
   CONCLUSION: The pendant carboxyl groups in PEK-L can react with epoxy groups of DGEBA during thermal curing, and covalently participate in the crosslinking network. PEK-L is thus expected to significantly improve the fracture toughness of DGEBA epoxy resin. (C) 2009 Society of Chemical Industry