Aromatic-Aliphatic Poly(butylene adipate-co-terephthalate) Bionanocomposite: Influence of Organic Modification on Structure and Properties

Bionanocomposite hybrids based on poly(butylene adipate-co-terephthalate) (PBAT) and layered silicates were prepared by melt interaction technique using corotating twin screw extruder having a blown film unit. Sodium montmorillonite (Na+MMT) along with three different commercially available nanoclays i.e., Cloisite30B (C30B), Cloisite20A (C20A), Bentonite (B109) have been used as a reinforcing agent. Wide angle X-ray diffraction (WAXD) studies indicated an increase in d spacing of the nanoclays in the bionanocomposite hybrids revealing formation of intercalated morphology. Morphological studies using transmission electron microscopy also confirmed that nanoclays were finely dispersed in the PBAT matrix and there was presence of partially exfoliated clay galleries along with intercalated structures in the bionanocomposite hybrids. Mechanical tests showed that the bionanocomposite hybrids prepared using B109 nanoclay exhibited higher tensile modulus. Functionalization of PBAT matrix upon grafting with maleic anhydride (MA) resulted in further improvement in mechanical properties. The existence of interfacial bonds in grafted bionanocomposite hybrids are substantiated using fourier transformation infrared spectroscopy. Thermal properties of bionanocomposite hybrids employing DSC, TGA also revealed improved T-g, T-c and thermal stability over the virgin polymer. Dynamic mechanical analysis indicated an increase of storage modulus (E') of PBAT biopolymer with incorporation of nanofiller. The biodegradability of PBAT bionanocomposite hybrids showed an increase in the rate of biodegradability with addition of Na+MMT due to hydrophilic nature of the nanoclay. POLYM. COMPOS., 31:1194-1204,2010. (C) 2009 Society of Plastics Engineers