A new‐type terephthalonitrile derivative flame retardant of bi‐DOPO compound with hydroxyl and amino groups on epoxy resin

Abstract

A new‐type flame retardant DEZ of bi‐DOPO compound containing bi‐hydroxy and two amino groups, was synthesized from terephthalonitrile, hydroxylamine hydrochloride, and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide, and used with curing agent 4,4′‐diamino‐diphenylmethane to prepare flame retard epoxy resin (EP) composites. 1H and 31P nuclear magnetic resonance spectra and Fourier transform infrared spectra have determined the chemical structure of DEZ. The properties of cured EP composites were explicitly evaluated by differential scanning calorimeter, thermogravimetric analysis, the limiting oxygen index (LOI), vertical burning (UL‐94) test, cone calorimetry test, and flexural test. The 1 wt% addition of DEZ could improve the EP composites by almost 14.4% of flexural strength and 29.6% of flexural modulus, respectively. The LOI of EP composites with 5 wt% of DEZ was 29.7% and EP composites reached a V‐0 rating in the UL‐94 test, as well as total heat release was decreased by 11.2%. All EP modified by DEZ exhibited a blow‐out effect in the combustion process, which was due to the release of pyrolysis gases and incombustible gases containing phosphorus radicals and nitrogen compounds.

Phospha-Mannich reactions of phosphinous acids R 2 P–OH and their derivatives

“…Yield, % Product Yield, % 91 [139] 98 [118] (-)* [140] (-)* [140] (-)* [140] (-)* [141] 92 [142,143] (-)* [140] (-)* [140] 91 [96] (-)* [144] (-)* [145] 77 [146] 63 [146] 60 [146] 58 [146] 69 [146] 59 [146] 60 [146] 61 [146] 63 [146] * Yield is not reported.…”

Chitosan as a Polyfunctional Crosslinker for a Renewable-Based Resorcinol Diglycidyl Ether

“…Sharif et al prepared chitosan-encapsulated graphene oxide to obtain diglycidyl ether of bisphenol A (DGEBA)-based nanocomposites with significant improvements in mechanical and thermal properties. In addition, chitosan was studied to achieve flame retardancy in thermosetting resins. − …”

A multi‐element flame retardant for rail transit to improve the flame retardant performance of epoxy resin while reducing smoke density

“…However, in the application scenario of rail transit, the greater threat to people is the smoke brought by combustion, which is highly toxic and dense and can easily cause people to suffocate. [9][10][11][12] According to the literature, the smoke suppression mechanism is mainly attributed to the gas phase and condensed phase, and the gas phase mainly promotes the full combustion of materials by inducing highly reactive free radicals to achieve the smoke suppression effect. 13,14 The condensed phase mainly reduces the volatilization of combustible molecules by promoting the formation of a heat-insulating carbon layer, while the introduction of flame retardants may block the free radical chain reaction in the gas phase to make it inadequate for combustion, so the improvement of flame retardants does not necessarily reduce the smoke density.…”