Aromatic-Aliphatic co-Polyester Poly (butylene adipate-co-terephthalate) Bio-Nanocomposite: Influence of Organic modification on Structure, and Properties.

Author : Sorna Rajendaran ( sorna.rajendran@gmail.com )

Abstract

Bio-nanocomposite hybrids based on poly (butylene adipate-co-terephthalate) (PBAT) and layered silicates were prepared by melt interaction technique using co-rotating twin screw extruder having 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. Wide Angle X-Ray Diffraction (WAXD) studies indicated an increase in d spacing of the nanoclays in the bio-nanocomposite hybrids revealing formation of intercalated morphology. Morphological studies using Transmission Electron Microscopy (TEM) 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 bio-nanocomposite hybrids. Mechanical tests showed that the bio-nanocomposite 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 bio-nanocomposite hybrids are substantiated using FTIR spectroscopy. Thermal properties of bio-nanocomposite hybrids employing DSC, TGA also revealed improved Tg, Tc and thermal stability over the virgin polymer. Dynamic Mechanical Analysis (DMA) indicated an increase of storage modulus (E’) of PBAT biopolymer with incorporation of nanofiller. The Biodegradability of PBAT bio-nanocomposite hybrids showed an increase in the rate of biodegradability with addition of Na⁺MMT due to hydrophilic nature of the nanoclay.

Key words: Poly (butylene adipate-co-terephthalate), TEM, DMA, MA-g-PBAT