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Development of a DOPO‐containing melamine epoxy hardeners and its thermal and flame‐retardant properties of cured products
Author(s) -
Xiong Yuanqin,
Jiang Zhuojuan,
Xie Yanyan,
Zhang Xuyong,
Xu Weijian
Publication year - 2012
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.37635
Subject(s) - limiting oxygen index , fire retardant , epoxy , melamine , thermal stability , materials science , melamine resin , thermogravimetric analysis , curing (chemistry) , polymer chemistry , formaldehyde , nuclear chemistry , char , composite material , chemistry , organic chemistry , pyrolysis , coating
In this study, a novel Schiff base of melamine used as flame‐retardant curing agent for epoxy resins, was synthesized via condensation reaction of 4‐hydroxybenzaldehyde with melamine, followed by the addition of 9,10‐dihydro‐9‐oxa‐10‐phosphaphen‐anthrene 10‐oxide (DOPO) to the resulting imine linkage. The structure of DOPO‐containing melamine Schiff base (P‐MSB) was characterized by Fourier transformed infrared spectroscopy, 1 H‐nuclear magnetic resonance ( 1 H‐NMR) and 31 P‐NMR. The compound (P‐MSB) was used as a reactive flame retardant in o ‐cresol formaldehyde novolac epoxy resin (CNE) to prepare flame‐retardant epoxy resins for electronic application. The thermal and flame‐retardant properties of the epoxy resins cured by various equivalent ratios phenol formaldehyde novolac (PN) and P‐MSB were investigated by the nonisothermal differential scanning calorimetry, the thermogravimetric analysis, and limiting oxygen index test. The obtained results showed that the cured epoxy resins possessed high T g (165°C) and good thermal stability ( T 5% , 321°C). Moreover, the P‐MSB/CNE systems exhibited higher limiting oxygen index (35) and more char was maintained in P‐MSB/CNE systems than that in PN/CNE system and the effective synergism of phosphorus–nitrogen indicated their excellent flame retardancy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013