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Studies on synthesis of modified epoxidized novolac resin from renewable resource material for application in surface coating
Author(s) -
Yadav Ranjana,
Awasthi Poonam,
Srivastava Deepak
Publication year - 2009
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/app.30581
Subject(s) - cardanol , materials science , epichlorohydrin , epoxy , fourier transform infrared spectroscopy , thermogravimetric analysis , curing (chemistry) , gel permeation chromatography , polymer chemistry , nuclear chemistry , chemical engineering , organic chemistry , chemistry , composite material , polymer , engineering
Five blend samples of cardanol‐based epoxidized novolac resin containing varying concentrations of carboxyl‐terminated poly(butadiene‐ co ‐acrylonitrile) (CTBN) ranging between 0 and 25 wt % with an interval of 5 wt % were prepared. The epoxidized novolac resin ( ECF ) was synthesized from the epoxidation of cardanol‐based novolac‐type phenolic resin ( CF ) with molar excess of epichlorohydrin (i.e., about 10 mol at 120°C in basic medium). The CF resin was synthesized with a molar ratio of 1 : 0.5 of CF using dicarboxylic acid catalyst such as succinic acid at 120°C for 5 h. The pure epoxy and its blend were cured with stoichiometric amounts of polyamine curing agent. The formation of various products during the synthesis of cardanol‐based novolac resin, epoxidized novolac resin, and blending of epoxidized novolac resin with CTBN have been studied by Fourier transform infrared (FTIR) spectroscopic analysis. Further, a reaction mechanism for the step‐growth reaction was proposed on the basis of the results of FTIR analysis. Also, the structures of CF and ECF were proposed on the basis of the results of nuclear magnetic resonance and MALDI‐TOF mass spectroscopic analysis along with gel permeation chromatographic (GPC) analysis. GPC analysis resulted in M n of 670 gmol −1 . The blend sample having 15 wt % CTBN concentration showed minimum cure time, whereas the presence of CTBN in blend systems showed marginal change in the values of Δ H . A clear‐cut two‐step mass loss in dynamic thermogravimetric trace of unmodified and CTBN‐modified systems was observed. Thermal stability of the blend sample containing 15 wt % CTBN into the pure epoxy resin was the highest among all other prepared systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009