Synthesis and properties of flame‐retardant epoxy resins based on DOPO and one of its analog DPPO

Abstract

Two phosphorus-containing heterocyclic flame retardants -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 2,8-dimethyl-phenoxaphosphin-10-oxide (DPPO) -and their derivatives were characterized and incorporated in the backbone of epoxy novolac to obtain flame-retardant epoxy resins. The structures and spectroscopic data including high-resolution mass spectroscopy of these flame retardants were determined. Flameretardant epoxy resins with a phosphorus content of up to 2% based on heterocyclic DOPO and DPPO were cured with 4,4 0 -diaminodiphenylmethane (DDM), and their features were examined by UL 94, LOI, and DSC. In this manner, high-performance polymers with glass transition temperatures around 1908C and the UL 94 rating V0 were obtained. These polymers were compared with epoxy resins incorporating diphenyl phosphite and diphenyl phosphate, which are nonheterocyclic and do not pass the UL 94 test up to 2% phosphorus. DPPO has a similar flame retardancy like the commercially available DOPO. Furthermore, to explain the difference in the efficiency of the tested flame retardants, key experiments for the determination of the active species during the flame-retarding process were performed and the PO radical was identified 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: [685][686][687][688][689][690][691][692][693][694][695][696] 2007

Effect of Meltable Triazine-DOPO Additive on Rheological, Mechanical, and Flammability Properties of PA6

“…Concerning the phosphorous-containing flame retardants, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives could be an attractive FR solution for PA6 due to their relatively higher thermal stability [25][26][27][28]. DOPO and its derivatives are known to predominantly act by a gas-phase mechanism, through the formation of PO¨radicals, which might also be assisted by a condensed-phase activity via the incorporation of specific functionalities at the DOPO moiety [25,29]. Despite the promising performance of these non-halogenated FRs, there are still some problems which need to be overcome.…”

Establishment of a highly efficient flame-retardant system for rigid polyurethane foams based on bi-phase flame-retardant actions

“…HQ was originally adapted for epoxy thermosets and exhibits prominent ame-retardant properties in the gas phase. [13][14][15] In addition, HQ can produce active POc radicals during its decomposition, which are capable of reacting with Hc and OHc radicals during the combustion process of the matrix to decrease heat release, prevent further oxidation and consequently suppress ame propagation. 16,17 Besides, the incorporation of HQ into polyurethane can improve the ame retardancy without changing the structure of the matrix, and there is no long-term migration phenomenon.…”

Flame retardant polyurethanes based on novel phosphonamidate additives

“…In the literature there exists numerous reports dealing with the synthesis and flame retardant application of alkyl DOPO-derivatives [9][10][11]. Additionally, one can also find several reports dealing with the synthesis and application as flame retardant of alkoxy DOPO-derivatives [12].…”