Study of the effect of modified and pristine carbon nanotubes on the properties of poly(vinyl alcohol) nanocomposite films

Nanocomposites of poly(vinyl alcohol) (PVA) and single-walled carbon nanotubes (SWNTs) in pristine form, or modified with poly (sodium 4-styrene sulfonate), were prepared in the form of films. The effect of SWNTs modification on their dispersion in the polymer matrix and on certain properties of the resulting composites, including tensile mechanical and thermal properties and swelling ability upon exposure to various moisture levels was studied. The composite films based on the modified SWNTs: (i) were characterized by a much higher degree of transparency up to 10%w/w loads, due to better dispersion, (ii) presented a higher hydrophilicity, and (iii) tended to promote thermal degradation of PVA to a lesser extent, as compared with the composites based on pristine SWNTs. A reinforcing effect was observed for the dry, 1% and 2.5% w/w modified-SWNTsPVA nanocomposites, without serious detrimental effects on the elongation at break. The effect of moisture on the mechanical properties was more intense in the case of composites based on modified SWNTs, as compared with those based on pristine SWNTs, in line with the observed higher hydrophilicity in the former case. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012