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 meltblending method using an extruder. Inorganic additives such as potassiumnitrate, zinc borate and magnesium hydroxide along with organic phosphinatehave been used to study their effect on thermal behaviour of PA66/claynanocomposites. The nanocomposites have been characterized by XRD whichconfirms the formation of intercalated and/or exfoliated nanocomposites. Thethermal degradation behaviour of nanocomposites has been studied by TG, DTA,DSC and FTIR. PA66/30B nanocomposite is thermally stable in the highertemperature range beyond 450 °C with increase in char yield due to formation ofnanocomposite and hindered diffusion of volatile products. DSC curve ofPA66/30B shows an endothermic peak at 452 °C with higher heat of absorption(378 J/g) during the decomposition stage due to intercalation of PA66 betweenthe 30B interlayers. The presence of a band in the FTIR spectrum in the range2224?2245 cm-1 in allPA66 nanocomposites char residue samples at 400 °C indicates the presence ofnitrile group in the degradation products of PA66. The addition of zinc boratealong with organic phosphinate induces a change in path of decomposition ofpolymer, leading to higher char formation which may protect the polymer fromburning.