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Novel star‐shaped and hyperbranched phosphorus‐containing flame retardants in epoxy resins
Author(s) -
Zang Lin,
Wagner Sebastian,
Ciesielski Michael,
Müller Patrick,
Döring Manfred
Publication year - 2011
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1990
Subject(s) - epoxy , diglycidyl ether , materials science , fire retardant , thermogravimetric analysis , oligomer , bisphenol a , monomer , condensation polymer , polymer chemistry , organic chemistry , chemistry , polymer , composite material
This report presents the synthesis and use of novel derivatives of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO, 1 ) and 5,5‐dimethyl‐1,3,2‐dioxaphosphorinan‐2‐one (DDPO, 2 ) as flame retardant additives for epoxy resins. DOPO‐based and DDPO‐based compounds were synthesized via nucleophilic substitution with 1,3,5‐tris‐(2‐hydroxyethyl) isocyanurate (THIC, 3 ) and subsequent oxidation (Schemes 1 and 2). Another trivalent DOPO derivative recently reported by our group was obtained by transamination followed by a Michaelis–Arbuzov rearrangement (Scheme 1). These products were blended into two epoxy resin systems [DEN 438 and diglycidyl ether of bisphenol A (DGEBA), both cured with dicyandiamide (DICY) and Fenuron] to obtain flame retardant thermosets. The flame retardancy and thermal properties of these epoxy resin systems were examined by UL 94‐V, Thermogravimetric analysis, and differential scanning calorimeter analysis. Furthermore, all reactions with phosphorus‐containing compounds were iterated employing the THIC oligomer, which was prepared via polycondensation of THIC (Scheme 3) using catalytic amounts of p ‐toluenesulfonic acid. In addition, Atherton–Todd reaction with the THIC oligomer was studied as a novel synthetic method for phosphorus‐containing flame retardants (Scheme 4). The resulting products were utilized as flame retardants in epoxy resins and compared with the analogous monomeric compounds. Copyright © 2011 John Wiley & Sons, Ltd.