Flame retardancy and thermal degradation of intumescent flame retardant polypropylene material

Influence of ammonium octamolybdate on flame retardancy and smoke suppression of PVC matrix flame retardant composites

In order to improve the flame retardancy and smoke suppression of polyvinyl chloride (PVC), ammonium octamolybdate (AOM)/nano-antimony trioxide (nano-Sb2O3)/dioctyl Phthalate (DOP)/PVC composites were prepared by high energy ball milling and melt blending methods using AOM as the smoke suppressant. The effects of AOM on the flame retardancy and smoke suppression of the PVC composites were studied by means of vertical burning tests (UL-94), limiting oxygen index (LOI), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and cone calorimetry (CCT). The results showed that the flame retardancy of PVC composites containing AOM was improved, namely the UL-94 grade of the composites reached the V-0 grade and the LOI increased from 22.3% to 30.6%, whilst the heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSR) and smoke factor (SF) decreased significantly. In addition, AOM could promote the dehydrochlorination reaction of the PVC composites at lower temperature, resulting in more compact and continuous char residues. Therefore, AOM is an effective smoke suppressant and has a good synergistic flame retardant effect with nano-Sb2O3 in flame retardant PVC matrix composites.

Flame Retardant Polypropylenes: A Review

Polypropylene (PP) is a commodity plastic known for high rigidity and crystallinity, which is suitable for a wide range of applications. However, high flammability of PP has always been noticed by users as a constraint; therefore, a variety of additives has been examined to make PP flame-retardant. In this work, research papers on the flame retardancy of PP have been comprehensively reviewed, classified in terms of flame retardancy, and evaluated based on the universal dimensionless criterion of Flame Retardancy Index (FRI). The classification of additives of well-known families, i.e., phosphorus-based, nitrogen-based, mineral, carbon-based, bio-based, and hybrid flame retardants composed of two or more additives, was reflected in FRI mirror calculated from cone calorimetry data, whatever heat flux and sample thickness in a given series of samples. PP composites were categorized in terms of flame retardancy performance as Poor, Good, or Excellent cases. It also attempted to correlate other criteria like UL-94 and limiting oxygen index (LOI) with FRI values, giving a broad view of flame retardancy performance of PP composites. The collected data and the conclusions presented in this survey should help researchers working in the field to select the best additives among possibilities for making the PP sufficiently flame-retardant for advanced applications.

Smoke suppression properties of ferrite yellow on flame retardant thermoplastic polyurethane based on ammonium polyphosphate

This article mainly studies smoke suppression properties and synergistic flame retardant effect of ferrite yellow (FeOOH) on flame retardant thermoplastic polyurethane (TPU) composites using ammonium polyphosphate (APP) as a flame retardant agent. Smoke suppression properties and synergistic flame retardant effect of FeOOH on flame retardant TPU composites were intensively investigated by smoke density test (SDT), cone calorimeter test (CCT), scanning electron microscopy (SEM), and thermal-gravimetric analysis (TGA). Remarkably, the SDT results show that FeOOH can effectively decrease the amount of smoke production with or without flame. On the other hand, the CCT data reveal that the addition of FeOOH can apparently reduce heat release rate (HRR), total heat release (THR), and total smoke release (TSR), etc. Here, FeOOH is considered to be an effective smoke suppression agent and a good synergism with APP in flame retardant TPU composites, which can greatly improve the structure of char residue realized by TGA and SEM results.