Abstract:In this study, the isolation and characterization of nanocellulose from pineapple leaf fibers (PLF) were carried out. Chemical pretreatment included pulping, bleaching, and acid hydrolysis to remove lignin, hemicellulose, and extractive substances were conducted. This was followed by high-shear homogenization and ultrasonication to produce nanocellulose. Morphological changes to the PLF due to treatment were investigated using scanning electron microscopy (SEM). This showed that the PLF had a diameter of 1-10 µm after high-shear homogenizing. Transmission electron microscopy (TEM) indicated that the nanofibers after ultrasonication for 60 min showed 40-70 nm diameters. Particle size analysis (PSA) indicates that the fibers had an average diameter of 68 nm. Crystallinity index was determined by X-ray diffraction (XRD) and had the highest value after acid hydrolysis at 83% but after 60 min ultrasonication, this decreased to 62%. Meanwhile, Fourier transform infrared (FTIR) spectroscopy showed there was no chemical structure change after acid hydrolysis. The most significant finding from thermal gravimetric analysis (TGA) is that the higher degradation temperature of nanofibers indicates superior thermal stability over untreated fiber. These results indicate that PLF waste could become a viable source of commercially valuable nanocellulose.

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Thermoplastic starch (TPS) reinforced by 1 wt % nanofiber cellulose (NFC) reinforcing from water hyacinth was produced. Ultrasonic vibration time (UVT) was applied to bionanocomposites during gelation for 0, 15, 30 and 60 min. Morphology of the NFC was investigated using Transmission Electron Microscopy (TEM). Scanning Electron Microscopy (SEM) and tensile tests were performed to identify the fracture surface and determine the mechanical properties of the bionanocomposites, respectively. The Crystallinity index (CI) of untreated and treated bionanocomposites was measured using X-ray Diffraction (XRD). The average diameter of NFC water hyacinth was 10-20 nm. The maximum tensile strength (TS) and modulus elasticity (ME) of the bionanocomposite was 11.4 MPa and 443 MPa respectively, after 60 min UVT. This result was supported by SEM which indicated good dispersion and compact structure.

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The isolation and characterization of nanocrystalline cellulose (NCC) from water hyacinth (WH) fibers were carried out. There are two treatments to obtain NCC from WH fibers by chemical and mechanical treatments. The chemical treatment involved alkalization with NaOH 25% in a highly-pressured tube, acid hydrolysis with 5M HCl, and bleaching with (NaClO2:CH3COOH) in ratio 5:2. The mechanical treatment was performed by using ultrasonic homogenizing at 12000 Rpm for 2 h. The morphological surface was observed by Transmission Electron Microscopy (TEM). TEM reported that the size of NCC was 10–40 nm. Crystallinity index and functional group analysis of the NCC WH fibers were also examined using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. XRD reported that the crystallinity index increased significantly after chemical and mechanical treatment due to the presents of crystalline area in the WH fibers. The crystallinity index of raw fiber, digester, bleaching, and ultrasonic homogenizing were 7%, 68%, 69%, and 73% respectively. The content cellulose of final product was 68% as measured by the chemical composition test. Meanwhile, FTIR reported that WH fibers after being given chemical treatment lead the functional group change due to removal hemicellulose and lignin. The result of XRD and FTIR were indicated that the sample of NCC WH fibers presents the structure of cellulose crystal type I.

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