Mechanical and water binding properties of carboxymethyl cellulose/multiwalled carbon nanotube nanocomposites

Carboxymethyl cellulose (CMC) composite films were prepared from CMC solutions (2% w/v) containing multiwalled carbon nanotubes (MWCNT) as nanofiller and glycerol (25% w/w CMC) as plasticizer. Tensile strength, elongation at break (EAB), young's modulus, water solubility, water swelling, water uptake, and water vapor permeability (WVP) for CMC films were 27.5 ± 2.5 MPa, 11.2 ± 0.8%, 198 ± 18 MPa, 57 ± 1.5%, 738 ± 25%, 124 ± 4%, and 0.55 ± 0.036 g.mm/m 2 .kPa.h, respectively. By increasing the relative humidity from 11.4 to 85.5%, the moisture absorption (MA) of CMC films was increased from 4 to 38%. Incorporation of MWCNT into the matrix caused a significant increase in the tensile strength, decrease in EAB, increase in young's modulus, decrease in water solubility, decrease in water swelling, decrease in water uptake, and decrease in MA. CMC/MWCNT films containing 1% MWCNT showed the lowest WVP. Scanning electron microscopy showed a good dispersion of MWCNT in the CMC matrix. CMC/MWCNT films containing >1% MWCNT showed significant antibacterial activities against both Gram‐positive and Gram‐negative bacteria in a dose‐dependent manner. Thus, good mechanical properties and water resistance along with strong antibacterial activities make CMC films grafted with MWCNT as a suitable packaging material. POLYM. COMPOS., 36:145–152, 2015. © 2014 Society of Plastics Engineers