Modified Carboxymethyl Cellulose/Halloysite Nanotube (CMC/HNT) Using Sodium Dodecyl Sulfate (SDS)

Abstract

In this research, the carboxymethyl cellulose (CMC)/halloysite nanotube (HNT) bio-nanocomposite films were prepared via the solvent casting method. The HNT content in the CMC/HNT bio-nanocomposite films was varied at 5%, 10%, 15% and 20% by weight, respectively. The effects of HNT content and chemical modification using sodium dodecyl sulfate (SDS) on the tensile properties, morphology, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopic analysis (FTIR), moisture content and X-ray diffraction analysis (XRD) of CMC/HNT bio-nanocomposite films were investigated. The results showed that the CMC films containing 10 wt% of HNT content possessed the highest tensile strength. The modulus of elasticity and elongation at break were increased with increasing HNT content for both untreated and treated systems. The field emission scanning electron microscopic analysis (FESEM) reveals that the poor interfacial interaction between CMC matrix and HNT nanofiller at high HNT content has led to poor HNT dispersion in untreated CMC/HNT bio-nanocomposites. Also, the thermal stability of untreated CMC/HNT bio-nanocomposites increased with increasing HNT content. The addition of HNT nanofiller also decreased the moisture content and decreased further with increasing HNT content. The XRD results also indicated that the peak's intensity correlated with crystallinity and basal spacing increased and achieved a higher value at 10 wt% of HNT content for both the untreated and treated systems. The treated CMC/HNT bio-nanocomposite films possessed higher mechanical and thermal properties compared with untreated CMC/HNT bio-nanocomposites. The FTIR spectra exhibited the formation of new peaks due to the changes in functional groups of treated CMC/HNT bio-nanocomposites. The improvement of dispersion and interfacial interaction between treated HNT nanofiller and CMC matrix were observed in FESEM images. The treated bio-nanocomposite films exhibited higher Tdmax and better thermal stability compared with untreated bio-nanocomposites. Furthermore, the chemical modifications also decreased the moisture content and enhanced the barrier properties of the treated CMC/HNT bio-nanocomposite films. The FTIR analysis showed the chemical modifications of HNT nanofiller significantly reduced the absorption peak on the hydroxyl group band. Moreover, the treated CMC/HNT bio-nanocomposite films further increased the peak's intensity and the basal spacing compared with untreated bio-nanocomposites in XRD analysis.