Cellulose surface modification for improved attachment of carbon nanotubes

This paper addresses an important issue related to improving the compatibility of the components when aiming to obtain composite materials with special properties. Thus, we designed and successfully prepared and characterized new materials based on multiwalled carbon nanotubes (MWCNTs) which are more efficiently and stably attached to viscose fibers, materials that may achieve semiconductive properties. The modification of the cellulosic fibers was performed by a selective oxidation reaction with sodium periodate, a process that ensures the formation of aldehyde groups onto the fibers surface, whereas the MWCNTs were modified by a two-step reaction, aiming at obtaining functionalized MWCNTs bearing HN₂ moieties. Meantime, two reference samples were additionally prepared for comparative purposes, combining one non-functionalized component with a functionalized one at a time. All samples were thoroughly characterized by FTIR and Raman spectroscopy, X-ray diffraction spectroscopy, while the morphology of the resulted composites was assessed by scanning electron microscopy (SEM). Thermal properties of the starting materials, functionalized components, and their corresponding hybrid materials were evaluated by thermogravimetric analysis. Electrical behavior of the raw and modified fibers and the both functionalized components was assessed. They exhibited low values of the contact resistance (10⁻⁴ MΏ) over the entire frequency range analyzed, as well as high values of field effect mobility, between 1.01 and 0.14 cm² V⁻¹ s in the frequency range 10⁻¹–10⁶ Hz.