Catalyzing carbonization function of ferric chloride based on acrylonitrile-butadiene-styrene copolymer/organophilic montmorillonite nanocomposites

A study on the Lewis acids-type transition metal chloride (FeCl3) catalyzing carbonization based on acrylonitrile-butadiene-styrene copolymer (ABS)/organophilic montmorillonite (OMT) nanocomposites has been achieved. The results of XRD, TEM and HREM experiments show the formation of intercalated structure. The thermal stability of the nanocomposites slightly decreases, but the char residue remarkably increases compared with pure ABS. Meanwhile, it is found that the loading of FeCl3 leads to crosslinking of ABS, promotes the charred residue yield and catalytic graphitization effect. The structure and morphology (XRD, HREM, SAED and LSR) of the purified char residue approve further the presence of graphite sheets. The possible catalyzing carbonization mechanism is composed of three prominent aspects. The first is the catalyzing effect of FeCl3 promoting the crosslinking of polymer. The second is the Hofmann degradation of OMT, whose degraded products have opposite role in promoting crosslinking reactions and the last is the nano-dispersed clay layers. The gas barrier properties of clay stop or reduce the release of the pyrolytic products, which have been dehydrogenated for more time and aromatized to form char. (c) 2006 Elsevier Ltd. All rights reserved.