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Curing and pyrolysis of cresol novolac epoxy resins containing BABODOPN
Author(s) -
Rwei S.P.,
Cheng C.Y.,
Liou G.S.,
Cheng K.C.
Publication year - 2005
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20305
Subject(s) - curing (chemistry) , materials science , limiting oxygen index , epoxy , thermal decomposition , activation energy , thermal stability , pyrolysis , char , glass transition , fire retardant , thermogravimetric analysis , thermosetting polymer , cresol , kinetics , polymer chemistry , nuclear chemistry , composite material , organic chemistry , chemistry , phenol , polymer , physics , quantum mechanics
Abstract This work investigates the curing kinetics, thermal stability, flammability, and decomposition kinetics of cresol novolac epoxy (CNE) cured with two curing agents, [1,4‐bis(3‐aminobenzoyloxy)‐2‐(6‐oxido‐6h‐dibenz(c,e)(1,2) oxaphosphorin‐6‐yl)‐naphthalene] (BABODOPN) and diamino diphenyl methane (DDM). The DSC curing study shows that the activation energy (E a ) can be estimated by Kissinger's method and the E a of CNE/DDM, 54.3 KJ/mole, is one‐half that of CNE/BABODOPN, 112.6 KJ/mole; also, the glass transition temperature (T g ) of the latter, 479.5 K, is substantially higher than that, 383 K, of the former. Both increases are attributed to the incorporation of phosphorus‐containing a bulky pendant aromatic group into the BABODOPN molecule, which inhibits its mobility. In comparison with the conventional DDM system, the phosphorus‐nitrogen synergistic effect of BABODOPN improves the limiting oxygen index (LOI) from 26 to 47, and increases the char yield from 30.4% to 38.3%. Moreover, the CNE/BABODOPN system even exhibits better flame retardancy than the excellent CNE/ODOPN system, developed by the authors previously, because of the synergistic effect. Finally, the investigation of thermal gravimetric analysis (TGA) decomposition in N 2 by Ozawa's method demonstrates that the mean E a declines as the phosphorus content increases, because the ease of decomposition of the phosphorus in the initiation stage facilitates the formation of an insulating layer. POLYM. ENG. SCI., 45:478–486, 2005. © 2005 Society of Plastics Engineers