Linlin Zang, S. Wagner, M. Ciesielski
Jul 1, 2011
Citations
1
Influential Citations
110
Citations
Quality indicators
Journal
Polymers for Advanced Technologies
Abstract
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.