Influence of steam explosion on chemical, mechanical, and thermal characterization of himalayan sisal fiber

Abstract

The present work focuses on the investigation of the chemical morphology, mechanical, and thermal properties of Himalayan sisal fiber (HSF) by using raw, alkaline-treated (NaOH), and steam explosion along with acid-treated HSF. Chemical compositions such as cellulose, hemicellulose, lignin, wax, and ash were examined in the current study. Alkaline-treated HSF showed the highest cellulosic constituent (85.04 wt.%) as compared to others. Mechanical (tensile force and tenacity) and thermal (TGA) studies depict that NaOH treated fiber is more efficient and more thermally stable as compared to untreated and acid treated HSF. The tensile force of 5 % NaOH-treated himalayan sisal fiber increased by 50.7 % and 35.29 %, respectively, as compared to raw and acid-treated fiber. Raw and treated HSF was subjected to thermogravimetric analysis (TGA). The most significant breakdown temperature arises from 355 °C for raw, 365 °C and 390 °C for acid and alkaline treatment. The thermal stability of alkaline-treated sisal fiber has been found to be higher as compared to raw and acid-treated sisal fiber. Fourier transfer-infrared (FTIR) spectroscopy study revealed that the change in peaks and intensity during the treatment can bring about change in the structure and potential improvements to the fiber. Crystallinity of HSF was investigated by X-ray diffraction (XRD). Alkaline-treated fiber showed the highest percentage crystallinity (Cr %), i.e., 63.18, as compared to raw (58.92 %) and acid-treated-steam exploded sisal fiber (62.90 %). The scanning electron microscope (SEM) investigation showed the sisal fiber's fracture, fiber pull-out and fiber breakage. In conclusion, Himalayan sisal fiber can be utilized to strengthen bio-composites in place of synthetic fibers for environmental sustainability.