Effect on thermal behaviour of polyamide 66/clay nanocomposites with inorganic flame retardant additives

摘要

Polyamide 66 (PA66)/clay nanocomposites have been prepared with inorganic additives by melt blending method using an extruder. Inorganic additives such as potassium nitrate, zinc borate and magnesium hydroxide along with organic phosphinate have been used to study their effect on thermal behaviour of PA66/clay nanocomposites. The nanocomposites have been characterized by XRD which confirms the formation of intercalated and/or exfoliated nanocomposites. The thermal degradation behaviour of nanocomposites has been studied by TG, DTA, DSC and FTIR. PA66/30B nanocomposite is thermally stable in the higher temperature range beyond 450 °C with increase in char yield due to formation of nanocomposite and hindered diffusion of volatile products. DSC curve of PA66/30B shows an endothermic peak at 452 °C with higher heat of absorption (378 J/g) during the decomposition stage due to intercalation of PA66 between the 30B interlayers. The presence of a band in the FTIR spectrum in the range 2224-2245 cm~(-1) in all PA66 nanocomposites char residue samples at 400 °C indicates the presence of nitrile group in the degradation products of PA66. The addition of zinc borate along with organic phosphinate induces a change in path of decomposition of polymer, leading to higher char formation which may protect the polymer from burning.