Facile Synthesis of Reduced-Graphene-Oxide-Modified Ammonium Polyphosphate to Enhance the Flame Retardancy, Smoke Release Suppression, and Mechanical Properties of Epoxy Resin

Abstract

A unique hybridized intumescent flame retardant named reduced-graphene-oxide-modified ammonium polyphosphate (RGO-APP) was successfully synthesized via the simple hydrothermal method and reduced process. Then, the obtained RGO-APP was applied in epoxy resin (EP) for flame retardancy reinforcement. The addition of RGO-APP results in a significant reduction in heat release and smoke production from the EP, which is attributed to EP/RGO-APP producing a more compact and intumescent char against the heat transfer and combustible decomposition, thus enhancing the fire safety of EP, as confirmed by char residue analysis. Especially, the EP containing 15 wt% RGO-APP acquires a limiting oxygen index (LOI) value of 35.8% and shows a 83.6% reduction in peak heat release rate and a 74.3% reduction in peak smoke production rate compared with those of pure EP. The tensile test exhibits that the presence of RGO-APP favors the enhancement in tensile strength and elastic modulus of EP due to the good compatibility between flame retardant and epoxy matrix, as supported by differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analyses. This work provides a new strategy for the modification of APP, thus facilitating a promising application in polymeric materials.

A systematic investigation of the transfer of polyphosphate/inorganic silicate flame retardants from epoxy resins to layered glass fiber‐reinforced composites and their post‐furnace flexural properties

“…proposed improved processability of SiAPP in epoxy resins in literature, 41 this does not reflect upon transfer to the composites. This phenomenon possibly results from interactions with the commercial sizing on the glass fibers.…”

N‐methylmorpholine‐N‐oxide molecules coated ammonium polyphosphates for dope spinning of flame‐retardant lyocell fiber

“…Additionally, the char residue value increases as the temperature rises to 600 C. This behavior is similar to flame-retardant epoxy resin when blended with reduced-graphene-oxide-modified APP. 35 This can be explained by the breakdown of APP into polyphosphoric acid during the heating process. The presence of polyphosphoric acid reduces the stability of cellulose, resulting in a lower smaller T onset .…”

Preparation and application of rosin@apatite hybrid material with new natural surfactants based on in-situ reaction by sol-gel method

“…The relevant studies on the use of hybrid materials as drug carriers and the related laws of the influence of the growth of AP materials on the charged micellar and the negatively charged dehydroabietic acid groups produced by electrostatic adsorption and hydrolysis were put forward [18,19]. Although hydrothermal method has the advantages of short reaction time [20,21], easy control of conditions and can regulate the interaction between solid and solvent, thus regulating nucleation and growth [22]. But the temperature in hydrothermal method is too high to retain organic matter so that the hybrid materials are mainly inorganic substances, and the organic substances are only templates.…”