A Nitrogen-Rich DOPO-Based Derivate for Increasing Fire Resistance of Epoxy Resin with Comparable Transparency

Abstract

To endow synergistically epoxy resin (EP) with excellent fire resistance and high optical transparency, a nitrogen-rich DOPO-based derivate (named as FATP) was synthesized and incorporated into EP. It showed that the incorporation of the FATP reduced the fire hazard of the EP, as demonstrated by the fact that the EP/4% FATP blends gained a UL-94 V-0 rating and an LOI value of 35%, with the lowest values of the THR (86.7 MJ/m2), the PHRR (1059.3 kW/m2), and the TSP (89.6 MJ/m2). The presence of the FATP also reduced the thermal stability and the crosslinking density whilst improving the curing reaction and the storage modulus of the EP/FATP blends. The TG-FTIR spectra showed that •HPO/•PO free radicals and some nonflammable gases (HN3 and NH3) were produced during the pyrolysis, and the characterization (SEM, Raman spectroscopy, and XPS) of char residues confirmed that the FATP facilitated the formation of continuous and compact carbon layers of greater graphitization degree. It was thus concluded that the FATP played the flame-retardant roles in both the gas and condensed phases. Furthermore, the FREPs kept almost identical transparency as the pristine EP, and mechanical properties were also slightly enhanced. The FREPs presented in this work show promising applications in the fields of advanced optical technology.

Improving processability and mechanical properties of epoxy resins with biobased flame retardants

“…Hydantoin EP is widely used in optical components, crafts and other fields due to its high transparency. Therefore, maintaining high transparency is essential for its applications in electronics, automotive coatings, optics and other fields 28 . The visible transmission spectra and transmittance values of the thermoset samples are presented in Fig.…”

“…Therefore, maintaining high transparency is essential for its applications in electronics, automotive coatings, optics and other fields. 28 The visible transmission spectra and transmittance values of the thermoset samples are presented in Fig. 4(a),(b).…”

A nitrogen‐rich DOPO‐based phosphoramide for improving the fire resistance of polycarbonate with comparable mechanical property

“…As a kind of phosphorus‐containing compound, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) has advantages such as high thermal stability, better antioxidant and hydrolysis resistance 26 . Especially, other flame retardant elements can be integrated into its molecular structure due to the high reactivity of the PH bond, many DOPO‐based derivatives containing other flame retardant element were accordingly synthesized and adopted to enhance the flame resistance of different polymer matrices (polyamide, 27,28 epoxy resin, 29,30 PC, 31–33 etc.). Recently, a series of organophosphorous compounds with nitrogen‐containing heterocycles have become great potential flame retardants due to their simple synthesis route, high thermal stability, good char‐formation and free radical quenching capacity 34–36 .…”

A Novel P/N/Si-Containing Vanillin-Based Compound for a Flame-Retardant, Tough Yet Strong Epoxy Thermoset

“…Diglycidyl ether of bisphenol-A (DGEBA) as an epoxide compound prepared from epichlorohydrin and bisphenol A is the most widely used type of EP, accounting for approximately 90% of the world’s total production of EPs [ 5 ]. Unfortunately, the high release of toxic flue gas upon combustion, flammability, and high brittleness greatly limit its further applications in advanced manufacturing fields such as chip encapsulation and smart devices [ 6 , 7 ]. The low impact strength and high brittleness of EPs will tremendously increase the odds of mechanical damage to EP-based electronics, thereby limiting their service life.…”