The Effect of Halloysite Nanotubes on the Fire Retardancy Properties of Partially Biobased Polyamide 610

Abstract

The main objective of the work reported here was the analysis and evaluation of halloysite nanotubes (HNTs) as natural flame retardancy filler in partially biobased polyamide 610 (PA610), with 63% of carbon from natural sources. HNTs are naturally occurring clays with a nanotube-like shape. PA610 compounds containing 10%, 20%, and 30% HNT were obtained in a twin-screw co-rotating extruder. The resulting blends were injection molded to create standard samples for fire testing. The incorporation of the HNTs in the PA610 matrix leads to a reduction both in the optical density and a significant reduction in the number of toxic gases emitted during combustion. This improvement in fire properties is relevant in applications where fire safety is required. With regard to calorimetric cone results, the incorporation of 30% HNTs achieved a significant reduction in terms of the peak values obtained of the heat released rate (HRR), changing from 743 kW/m2 to about 580 kW/m2 and directly modifying the shape of the characteristic curve. This improvement in the heat released has produced a delay in the mass transfer of the volatile decomposition products, which are entrapped inside the HNTs’ lumen, making it difficult for the sample to burn. However, in relation to the ignition time of the samples (TTI), the incorporation of HNTs reduces the ignition start time about 20 s. The results indicate that it is possible to obtain polymer formulations with a high renewable content such as PA610, and a natural occurring inorganic filler in the form of a nanotube, i.e., HNTs, with good flame retardancy properties in terms of toxicity, optical density and UL94 test.

Improvement the Flame Retardancy and Thermal Conductivity of Epoxy Composites via Melamine Polyphosphate-Modified Carbon Nanotubes

“…Therefore, after 200 s, the output of harmful gas CO of the composites EP/CNTs-M10 was higher than that of pure epoxy resin. This observation is often common for flame retarded polymer composites, which arises from decreased combustion efficiency leading to non-complete burning of the organic materials [ 33 , 34 , 35 , 36 ]. The peak value of CO gas produced by EP/CNTs-M10 composite was 0.018 g/s, which was lower than the peak value of CO gas produced by pure EP (0.02 g/s).…”

Investigation of the Fire Performance of Polyamide 6-Based Composites with Halogen-free Flame Retardants and Synergistic Materials

“…The flammability parameters include the time to ignition (TTI), peak heat release rate (PHRR), total smoke rate (TSR), total heat release (THR), time of peak heat release rate (tPHRR), fire growth rate (FIGRA), effective heat combustion (EHC), and maximum average rate of heat emission (MAHRE). Another important parameter during combustion produced by fire is the amount of CO and CO 2 released from the burned products due to the fact that a great release could cause anoxia conditions . It is known that death in a fire disaster is mainly owing to the production of CO .…”

Flame Retardant Coatings: Additives, Binders, and Fillers

“…One of the typical polyamides used in many industrial applications is polyamide-6,6 with many amide bonds in the main chain, allowing it to have good processing properties, low melt viscosity, excellent thermal and mechanical, strong chemical and electrical resistance, as well as fatigue and abrasion resistance [ 210 , 211 ]. However, polyamide-6,6 exhibits flammability and smoke-emitting issues, endangering people and the environment, thus limiting its widespread use in high-temperature fields [ 212 ].…”