Polyvinyl Alcohol Fuller’s Earth Clay Nanocomposite Films Pratibha Pandey, 1 Arup Ranjan Bhattacharyya, 2 Pranav Kumar Gutch, 1 Ram Singh Chauhan, 1 Satish Chandra Pant 1 1 Defence R&D Establishment, Jhansi Road, Gwalior, India 2 Department of Metallurgical Engineering and Material Science, Indian Institute of Technology Bombay, Mumbai, India Received 30 October 2007; accepted 22 October 2008 DOI 10.1002/app.31399 Published online 30 October 2009 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: Nano fuller’s earth was prepared by milling and subsequent sonication of clay. The polyvinyl alcohol (PVA) and PVA -Nano clay composite films were prepared by solution casting method. The films were characterized for their structural, mechanical, and thermal properties using electron microscopes (SEM, TEM), Tensile Tester, dynamic mechanical analyzer (DMA), thermo gravimetric analyzer (TGA), and Raman spec- troscopy. The nanocomposite films showed improvement in me- chanical properties, viscoelastic behavior as well as resistance towards thermal degradation. Uniform distribution of clay due to intimate interaction between clay and polymer appears to be the cause for improved properties. V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 3005–3012, 2010 Key words: polyvinyl alcohol; Fuller’s earth clay; nanocomposite; films; mechanical properties INTRODUCTION Considerable efforts are being directed to evolve newer materials using nanoparticles for preparation of polymer inorganic hybrids, both with the aim of property enhancement and development of applica- tions. 1,2 Polymer nanocomposites have been shown to provide unique combinations of mechanical and thermal properties often at very low filler weight fraction. The improved properties of nanocomposits over conventional composite have been attributed to the intimate mixing of material at nanometer domain and the large surface area of filled particles. It is also reported that polymer crystallization near an inorganic surface produces nucleating or epitaxial effect. The behavior is known to promote growth of a different crystal phase and stabilizes the bulk crys- tal phase in certain cases. 3–8 Interactions both at the macro and nano level lead to property enhancement of the composites. Sumita et al. reported dramatic improvement in the yield stress (30%) and Youngs modulus (170%) in nano clay filled polypropylene compared to mi- crometer clay filled polypropylene. 9 Various other combinations of polymer-clay nanocomposite have been reported in the literature with improved me- chanical and thermal properties with 2–10 wt % add–on of nanoparticle filler. 6,7,10,11 Notwithstanding to the susceptibility of polyvinyl alcohol (PVA) towards water and moisture, it is attracting a great deal of attention. Recently a method developed in France to disperse carbon nanotubes in PVA water solution and spinning fibers from it. 12–15 Baughman et al. 16 showed that high nanotube contening PVA fibers had a tensile strength half that of Kevlar V R and toughness 17 times that of Kevlar V R and three times that of spider silk. The resulting toughness of the fiber arises from chain extension in amorphous regions of PVA sup- ported by rigid nanotubes functioning as crystalline blocks. Slippage between individual nanotubes within bundles might also contribute to toughness. Recently Podsiadlo 17 et al. have reported layer by layer (LBL) assembly of PVA and montmorillonite clay resulting in multilayer nanocomposite films. The amount of clay was determine to be  70 wt % by TGA. The nanocmopsite displayed  4 times higher strength and nearly one order of magnitude higher modulus than pure PVA polymer. Studies on excellent mechanical properties of PVA nano-composite films/fibers motivated our work on fuller’s earth (FE) PVA nanocomposite. The aim of present study is to explore the possibility of synthe- sizing environment friendly biodegradable high strength cost effective nanocomposite films based on low cost commercially available FE clay and PVA. Such plastics are needed for environmental friendly applications like packaging materials (trash bags, Correspondence to: P. Pandey (rkpratibha@yahoo.com). Journal of Applied Polymer Science, Vol. 115, 3005–3012 (2010) V C 2009 Wiley Periodicals, Inc.