A novel intumescent flame‐retardant system for flame‐retarded LLDPE/EVA composites

Abstract

A new intumescent flame retardant (IFR) system consisting of ammonium polyphosphate (APP) and charing-foaming agent (CFA) and a little organic montmorillonite (OMMT) was used in low-density polyethylene (LLDPE)/ethylene-vinyl acetate (EVA) composite. According to limiting oxygen index (LOI) value and UL-94 rating obtained from this work, the reasonable mass ratio of APP to CFA was 3 : 1, and OMMT could obviously enhance the flame retardancy of the composites. Cone calorimeter (CONE) and thermogravimetric analysis (TGA) were applied to evaluate the burning behavior and thermal stability of IFR-LLDPE/EVA (LLDPE/EVA) composites. The results of cone calorimeter showed that heat release rate peak (HRR-peak) and smoke production rate peak (SPR-peak) and time to ignition (TTI) of IFR-LLDPE/EVA composites decreased clearly compared with the pure blend. TGA data showed that IFR could enhance the thermal stability of the composites at high temperature and effectively increase the char residue. The morphological structures of the composites observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) demonstrated that OMMT could well disperse in the composites without exfoliation, and obviously improve the compatibility of components of IFR in LLDPE/EVA blend. The morphological structures of char layer obtained from Cone indicated that OMMT make the char layer structure be more homogenous and more stable.

Flame Retardance and Smoke Suppression of CFA/APP/LDHs/EVA Composite

“…It is used both as a charring agent and as a foaming agent in intumescent flame retardants (IFR) due to its excellent flame retardant properties and water resistance. To improve the flame retardance and thermal stability of polymer (polypropylene, EVA, polyethylene), CFA and ammonium polyphosphate (APP), systems with different synergistic agents (such as zinc borate, zeolites, organic montmorillonite) have been investigated in the previous report [17][18][19][20][21][22]. However, the research on the combination of LDHs and CFA/APP as synergistic flame retardants in EVA composites has never been reported.…”

Effect of a novel phosphorus‐containing compound on the flame retardancy and thermal degradation of intumescent flame retardant polypropylene

“…5,6 Among organic flame retardants, intumescent flame retardants (IFRs) are well known as a new generation of flame retardants due to their merits, such as low smoke emission and toxic gases produced during burning, and antidripping property. [6][7][8][9] IFRs consist of three components: acid source [e.g., ammonium polyphosphate (APP)], carbonization source (e.g., pentaerythritol), and blowing agent (e.g., melamine). Besides, the synergistic agents (e.g., zeolite) have been used to enhance the flame retardancy of IFRs, and only the ''components'' reasonable match can promote the IFR systems to form a stable swell char layer.…”

Study on the flame retardancy of EVM/magnesium hydroxide composites optimized with a flame retardant containing phosphorus and silicon

“…Commonly, intumescent flame retardants could generate a swollen multicellular thermally stable char on heating which insulated the underlying material from the flame action and resulted in the extinguishment of combustion. 37,38 Moreover, compared with EVM/SPDV composite without MDH, the dispersed MDH in EVM matrix provided a mechanical strength to the whole compounds, and the increase of viscosity for the optimized EVM/MDH composites can better maintain the original shape without seepage of the melted polymer in combustion and improve the stability of the char layer, which was beneficial to reduce the transfer rate of volatile and play a more effective flame retardant effect for SPDV in solid state.…”