Graphene oxide nano-layers functionalized/reduced by L-Citrulline/Pectin bio-molecules for epoxy nanocomposite coating mechanical properties reinforcement

• Published in: Progress in organic coatings 2023-05, Vol.178, p.107493, Article 107493
• Main Authors: Shahmoradi, Ali Reza, Bejandi, Mohsen Saket, Rasanani, Elmira Hadian, Javidparvar, Ali Asghar, Ramezanzadeh, Bahram
• Format: Article
• Language: English
• Subjects: Epoxy-based nanocomposite; Graphene oxide; L-Citrulline; Mechanical properties
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2023.107493

In this work, graphene oxide (GO) was reduced/modified by an eco-friendly route using L-Citrulline molecules extracted from the watermelon rind. Before and after the modification/reduction process, the rGO layers were characterized by different spectroscopy techniques. In addition, the mechanical properties of the epoxy-rGO reinforced coatings were evaluated by tensile and dynamic mechanical thermal analysis (DMTA) tests. The characterization results have demonstrated that the GO nanosheets were successfully reduced/modified by the extracted compounds. DMTA analysis showed that the values of storage modulus at glassy and rubbery regions for the neat epoxy sample incorporated with the rGO nanosheets were increased by about 39 % and 97 %, respectively. Moreover, the glass transition temperature (Tg) was increased from 76.8 °C for the neat epoxy (EP) to 84.0 °C for the EP/modified-reduced GO nanocomposite. Tensile tests showed that the values of tensile strength, maximum strain, elastic modulus, and toughness of the epoxy-based coating were respectively increased by about 142 %, 266 %, 46.7 %, and 388 % after incorporation of the rGO nanosheets compared to the EP sample. [Display omitted] •L-Citrulline molecule extracted from watermelon rind was used as an eco-friendly reducing agent for graphene oxide.•The reduced-surface modified GO nanosheets were used as the reinforcement of an epoxy-based nanocomposite.•Modified GO nanosheets improved the tensile strength and energy at break of epoxy coating about 142% and 388%.•The reduction/modification process led to the improvement of the GO sheets dispersion and interactions in epoxy matrix.