Intumescent flame retardant polyurethane/reduced graphene oxide composites with improved mechanical, thermal, and barrier properties

Abstract

Intumescent flame retardant polyurethane (IF-RPU) composites were prepared in the presence of reduced graphene oxide (rGO) as synergism, melamine, and microencapsulated ammonium polyphosphate. The composites were examined in terms of thermal stability (both under nitrogen and air), electrical conductivity, gas barrier, flammability, mechanical, and rheological properties. Wide-angle X-ray scattering and scanning electron microscopy indicated that rGO are well-dispersed and exfoliated in the IFRPU composites. The limiting oxygen index values increased from 22.0 to 34.0 with the addition of 18 wt% IFR along with 2 wt% rGO. Moreover, the incorporation of rGO into IFRPU composites exhibited excellent antidripping properties as well as UL-94 V0 rating. The thermal stability of the composites enhanced. This was attributed to high surface area and good dispersion of rGO sheets induced by strong interactions between PU and rGO. The oxygen permeability, electrical, and viscoelasticity measurements, respectively, demonstrated that rGO lead to much more reduction in the gas permeability (by *90 %), high electrical conductivity, and higher storage modulus of IFRPU composites. The tensile strength, modulus, and shore A remarkably improved by the incorporation of 2.0 wt% of rGO as well.

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

“…21 The second degradation stage at 400-800 C is primarily the degradation of substituted urea resulting from the reaction of carbodiimide with alcohol or water. 22 In the presence of EG, both the T 5% and the T max1 of the PU/EG composites are shied to a lower value compared with pure PU and decrease with increasing EG loading.…”

Graphene-based flame retardants: a review

“…To solve the abovementioned problems, many researchers have made significant efforts to use graphene as an adjuvant in combination with other conventional flame retardants such as intumescent flame retardants and aluminium hydroxide [46][47][48][49][50][51], melamine polyphosphate [52], carbon black [53], layered double hydroxides (LDHs) [54], brominated polystyrene and antimony trioxide (Sb 2 O 3 ) [55], and aluminium hypophosphite [56]. As shown in Fig.…”

“…The PHRRs are reduced dramatically as compared with pure polymer matrix, which means that polymer composites are more secure in case of fire. For example, Gavgani et al [46] reported that the intumescent flame retardant polyurethane (IFRPU) prepared with rGO (dosage: 0.2 %), melamine and microencapsulated ammonium polyphosphate exhibits not only compensated thermal stability and mechanical properties but also improved antidripping properties (indicated by a UL-94 V0 rating and self-extinguishing) as well as increased storage modulus, char yield and thermal stability. The reason lies in that rGO is well dispersed with little agglomeration (Fig.…”

Intumescing multilayer thin film deposited on clay-based nanobrick wall to produce self-extinguishing flame retardant polyurethane

“…A common technique for retarding the flammability of PUF is to introduce bromine-based molecules that scavenge (H • and OH • ) radicals in the gas phase [5,6], but these halogenated additives are undergoing worldwide scrutiny for the toxic smoke they release and their potential to leach into the environment [7][8][9]. Platelet-based and intumescent nanocoatings have been developed in recent years to address these issues [10][11][12][13][14][15][16][17][18][19][20].…”