Effect of Alkaline Treatment and Graphene Oxide Coating on Thermal and Chemical Properties of Hemp (<i>Cannabis Sativa L</i>.) Fibers
Pedro Henrique Poubel Mendonça da Silveira, Matheus Pereira Ribeiro, Thuane Teixeira da Silva, Andreza Menezes Lima, Maurício Ferrapontoff Lemos, Anthony Garotinho Barros Assed Matheus de Oliveira, Lúcio Fábio Cassiano Nascimento, Alaelson Vieira Gomes, Sérgio Neves Monteiro
Abstract
The constant concern about environmental issues has led to the growth of researches about eco-friendly materials. Among them, the natural lignocellulosic fibers have already presented their potential in place of petroleum-based synthetics. However, a relevant number of studies still have to deal with their disadvantages, such as the weak bond on the matrices for a composite performance and limited thermal performance. Thus, the present study analyzes a combination of alkaline treatment and graphene oxide coating in hemp fibers, an NLF applied in several products but with few investigations in engineering applications. The hemp fibers were thermally characterized with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The GO-coating was evidenced by the Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Changes in crystallinity were presented by X-ray diffraction (XRD). It was observed an increase of about 4% to 11% of the crystallinity after the alkaline treatment. The thermal stability rose about 13°C in the 10 wt% NaOH-treated and GO-coated fibers, and a change of about 3.5°C was detected for the glass transition temperature. The GO-coating effect was also evidenced by changes in Raman spectra and FTIR curves and was visually detected in the scanning electron microscope (SEM).