Flame retardancy of epoxy resin nanocomposite with a novel polymeric nanoflame retardant

Abstract

A wrapped nanoflame retardant, designated as polyhedral oligomeric silsesquioxane (POSS)‐poly(4‐bromostyrene) (PBS)‐carbon nanotubes (CNTs), was synthesized via π‐π stacking interactions between the walls of multiwalled carbon nanotubes and the silicon‐bromine containing hybrid copolymer (designated as POSS‐PBS) that was copolymerized by 4‐bromostyrene and acryloyloxyisobutyl polyhedral oligomeric silsesquioxane. The POSS‐PBS‐CNTs exhibited good dispersibility in epoxy resin (EP) without obvious aggregation. Furthermore, the fire behaviors of this flame‐retardant EP (FR‐EP) nanocomposites were examined via limited oxygen index (LOI) and cone calorimeter (CONE) tests. The FR‐EP had an ideal LOI value of 35.3% and its residual char yield obtained from CONE test was significantly enhanced from 5.9% to 15.3% with the incorporation of 4 wt% POSS‐PBS‐CNTs and 1.33 wt% Sb2O3 into EP matrix. Additionally, the addition of 4 wt% POSS‐PBS‐CNTs or POSS‐PBS can efficiently decrease the peak heat release rate (PHRR) of EP matrix by 41.0% or 45.6%, respectively.

A novel multifunctional phosphorous and nitrogenous reactive flame retardant toward epoxy resins by one‐pot method

“…Furthermore, P, O, C, and N were uniformly distributed over the char of EP/4% DB‐DAD, and the P content increased with the increase of DB‐DAD load, thus contributing to the flame retardancy. Besides, the relative content of different elements can also evaluate the flame‐retardant effect, and a higher C/O ratio means a better thermal oxidation resistance 41 . The C/O ratio of neat EP (3.59) was significantly lower than that of EP/4% DB‐DAD (4.49) because the phosphorous groups in DB‐DAD can promote and participate in the formation of carbon layer, thus showing a good condensed phase flame‐retardant effect.…”

Recent Developments in the Flame-Retardant System of Epoxy Resin

“…[133]. The well-known advantages of silicon-based flame retardants, such as halogen-free, low-smoke, low-toxicity characteristics have attracted wide attention from researchers [134,135]. The main flame retardant mechanism of silicon-based flame retardant is to form a cracked carbon layer and improve the oxidation resistance of the carbon layer [136].…”

POSS‐modified ammonium polyphosphate for improving flame retardant of epoxy resins

“…Polyhedral oligomeric silsesquioxanes (POSS) are new hybrid materials with an inorganic Si‐O core and bulky organic substituents on the outer surface, such as aryl, arylene, alkylene, epoxy group, and so on 23–25 . They have been proven to improve the flame retardancy, thermal stability, and mechanical property of polymers 26 . Several different types of POSS have been used in EP to confirm that the incorporation of POSS can noticeably improve composites' thermomechanical properties 27 .…”