Synergistic effects of molybdenum disulfide on a novel intumescent flame retardant polyformaldehyde system

Abstract

A novel intumescent flame retardant (IFR) composed of ammonium polyphosphate (APP), benzoxazine containing trialkoxysilane (BA‐a‐Si) and melamine (ME), is compounded with different specifications of MoS2 as synergist to flame retard polyformaldehyde (POM). The flame retardancy and mechanism of the composites are analyzed by limiting oxygen index (LOI), vertical combustion (UL‐94) and cone calorimeter. At the same time, the mechanical properties and lubricating properties are tested by electromechanical testing machine and wear testing machine. The experimental results show that MoS2 has a good synergistic effect with IFR, and the smaller the average particle size of MoS2 is, it seems to be more beneficial to improve the flame retardancy of POM composites. Only a small amount of MoS2 (0.8 wt%) is needed to synergize with IFR, the flame retardant POM composite (FR‐POM) can achieve UL‐94 (3.2 mm) V‐0 rating, LOI of 62.5%, and heat release rate reduction of 25.3%, total smoke release decreased by 29.5%. In addition, from the mechanical properties analysis, it is found that the microscale MoS2(M2) can better improve the bending and tensile properties of the FR‐POM composites, while the nanoscale MoS2(N80) is more helpful to improve the lubricating properties.

Synergistic Flame Retardant Properties of Polyoxymethylene with Surface Modified Intumescent Flame Retardant and Calcium Carbonate

“…It can be seen from Figure 7 that the decomposition trends of FR-POM composites under N 2 and air atmospheres are almost the same, both showing one-step decomposition. However, the N 2 atmosphere seems to be more conducive to the formation of carbon residues, which may be due to the participation of oxygen in the air atmosphere to generate CO 2 , thereby reducing the amount of carbon residues [ 41 ]. In both atmospheres, the initial decomposition temperature T -5% of P0 is around 233 °C, T -10% is around 248 °C, and the fastest decomposition temperature is about 295 °C.…”

“…At this point, the BOZ carbonating agent comes into play. The pyrophosphoric acid and metaphosphate decomposed by APP catalyze the esterification and crosslinking of BOZ, and finally make it become a stable carbon layer with a three-dimensional network structure, which greatly improves the density and strength of the carbon layer, thus blocking the communication channel between the combustible gas in the matrix and the external heat source, and finally interrupts the combustion process [ 41 ]. The addition of calcium carbonate further catalyzes BOZ and plays a stronger catalytic carbonization role in the matrix, thus accelerating the formation of the carbon layer.…”

Recent advances in metal-family flame retardants: a review

“…Yang et al synthesized a new IFR by using APP, benzoxazine of trialkoxysilane (BA-a-Si), melamine (MEL) and MoS 2 as synergists for flame retardant paraformaldehyde (POM). 106 According to experimental findings, MoS 2 and IFR work well together. Only a small amount of MoS 2 (0.8 wt%) is required to synergise with IFR, and flame-retardant POM composites (FR-POM) can achieve UL-94 V-0 rating with LOI of 62.5%, 25.3% reduction in exotherm rate and 29.5% reduction in total smoke emission.…”

Facile Ball Milling Preparation of Flame-Retardant Polymer Materials: An Overview

“…Molybdenum disulfide (MoS 2 ) consists of the elements Mo and S. Mo is a transition metal and demonstrates catalytic ability and smoke suppression performance [ 93 , 94 ]; S is also a flame-retardant element. MoS 2 has a layered structure, and can be exfoliated into nanosheets, the high specific area of which is in favor of improving catalytic performance.…”