Halloysite modified by melamine cyanurate and its compositions based on PA6

Abstract

The results of the investigation on the synthesis and applications of halogen-free hybrid flame retardants (HFR) are presented. HFR were obtained by in situ modification of halloysite (HNT) with melamine cyanurate (MC). The reactions were conducted with and without the presence of poly(vinyl alcohol) (PVA) as a protective colloid. The modification of HNT was confirmed by using infrared spectroscopy (IR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and transmission electron microscopy (TEM) analyses. The thermal properties of flame retardants were investigated as well. The obtained HFR were introduced into polyamide 6 (PA6). The relationship between a type of HFR and its effectiveness in reducing the flammability as well as in improvement of mechanical properties of polymer composites was investigated. It was found, that depending on the type of applied HFR, the value of the oxygen index (OI) of the obtained composites was within 29-34.5 %. In turn, the use of PVA in the synthesis of HFR increased the flexibility of the compositions containing this type of HFR.

Natural halloysite nanotubes decorated with organophosphorous for highly flame‐resistant epoxy composites

“…32 More importantly, HNTs are structurally stable and do not decompose at high temperatures, they can form a physical barrier to protect the interior of the material. 33 These advantages make HNTs exhibit promising potential in the flame retardancy field. [34][35][36] Even so, it should be noted that it is still very difficult to achieve a high flame resistance of EP composites by incorporating a single kind of HNTs.…”

“…These hydroxyl groups can also be removed to form water to take away some heat at high temperatures 32 . More importantly, HNTs are structurally stable and do not decompose at high temperatures, they can form a physical barrier to protect the interior of the material 33 . These advantages make HNTs exhibit promising potential in the flame retardancy field 34–36 .…”