Thermal, Morphological, and Structural Characterization of Seven-Islands-Sedge (Cyperus malaccensis) Fiber with Graphene Oxide as a Coupling Agent for Future Polymer Composite Reinforcement

Abstract

Natural lignocellulosic fibers (NLFs) are gaining attention for their use as a reinforcement in traditional and biodegradable polymer matrices due to their renewability, eco-friendliness, cost-effectiveness, and low energy processing requirements. On the other hand, their compatibility with the polymer matrix is limited because of the difference in their hydrophilicity and the hydrophobic nature of polymers. Graphene oxide (GO) is a material gaining interest in its use as a coupling agent between the matrix interface of NLF/polymer owing to its amphiphilic nature. Therefore, this study aims to investigate the application of GO coating on the seven-islands sedge (Cyperus malaccensis), sedge fiber for short. The coating was done using 0.1% of the weight of the fiber. A comparison was made between untreated sedge fibers and those treated with a GO coating regarding their thermal behavior, morphological aspect, and structural characterization. Based on the TGA/DTG curves obtained from thermogravimetric analysis, it was observed that the GO coating resulted in better thermal stability properties. The curves obtained from the differential scanning calorimetry indicated the presence of both endothermic and exothermic peaks that correspond to the microstructures of the fiber. The Fourier transform infrared spectrum confirmed the presence of bands associated with the structure of GO. According to the X-ray diffraction data, there was an increase in the size of the crystallites, which enhanced the adhesion interface. Additionally, the scanning electron microscopy images revealed an effective coating of GO on the surface of the natural fiber. The average roughness parameter (Ra) obtained from an analysis carried out using a profilometer, revealed Ra = 4.623 ± 0.753 and 3.767 ± 1.130 for the untreated sedge fiber and GO-treated sedge fiber, respectively.

Keywords

• GO coating
• coupling agent
• sedge fibers
• polymer reinforcement
• thermal behavior
• GO涂层