Investigation of thermal property and flame retardancy of ABS/montmorillonite nanocomposites

Acrylonitrile-butadiene-styrene (ABS)/montmorillonite (MMT) nanocomposite was prepared by melt blending of ABS and organomodified montmorillonite (OMMT). X-ray diffraction, TEM and Fourier transform infrared spectra were used to characterise the morphology and structure of the nanocomposites. Thermal stability and flame retardancy of the nanocomposites were studied by thermogravimetric analysis, cone calorimetry, limit oxygen index and UL94 test. The basal spacing of sodium MMT was found to increase from 1.46 to 2.69 nm after modification by cetyltrimethyl ammonium bromide, and,3.3 nm after melt blending with ABS. Transmission electron microscope observation showed that organo-MMT was intercalated and exfoliated in ABS. The results by cone calorimetry analysis indicated that the reduction of the peak heat release rate of ABS/OMMT nanocomposites (with 5% OMMT loading) and ABS/OMMT/triphenyl phosphate (TPP) nanocomposites (with 4% OMMT and 10% TPP loading) was 47.3 and 57.3% respectively, while the total heat released decreased by about 10 and 17% and the mass loss rate decreased by about 41 and 53% respectively, as compared with pristine ABS. Limit oxygen index value of ABS/OMMT and ABS/OMMT/TPP nanocomposites increased to 22.8 and 28% from 18% of pristine ABS respectively. The vertical burning test (UL-94V) results revealed that the nanocomposites could achieve V-0 grade.