Cellulose nanocrystals (CNCs) are charged nanoparticles with a high aspect ratio derived from the most common biological polymer, cellulose. Acid hydrolysis is one of the most common methods for CNC production. Whatman #1 filter paper was hydrolyzed by sulfuric acid and characterized by AFM in this research to examine the morphology and size distribution of CNCs. One drop of CNC suspension was air-dried on microscope cover glass to be analyzed by AFM with non-contact mode. The CNC dimensions were determined by measuring individual and isolated particles (n=88) via Nanosurf Easyscan2 software. The measurement data was analyzed by Excel statistically. Synthesized CNCs were ellipsoidal with the length, height, and aspect ratio of 219.87 ± 42.12, 6.25 ± 2.27, and 41.17 ± 21.70 nm, respectively. Although the length and height of the produced CNCs were in acceptable range, but the width of CNCs was an overestimation and it was not reliable, mostly due to AFM tip broadening effect. Particle size measurement of CNCs is a challenging process because of their rapid aggregation and rod shape. Although hydrolysis parameters are influential on the final shape and size of CNCs, but it is necessary to optimize and maximize the quality of sample preparation and AFM adjustment to obtain the size of CNCs with the most accuracy and reliability. The CNC dimensions were determined by AFM are slightly different in the literature but height (thickness) is the most reliable one based on this experiment. Further studies are required to standardize CNC size measurement by AFM.

In this study, the synergic effects of cellulose nanocrystal and nanoclay on the biodegradation and migration behavior of composite films based on polylactic acid (PLA) were investigated. PLA and PLA-based nanocomposite films containing different loads of cellulose nanocrystal and nanoclay (0, 3 and 5 wt % each) were fabricated using a solvent casting method. In order to improve the compatibility and miscibility of the whole system with respect to PLA matrix, cellulose nanocrystal was treated with oleic acid. For evaluating the biodegradation and migration behavior of films, the enzymatic degradation, biodegradation, buried in soil and compost; and overall migration were tested. The results indicated that the biodegradability of the composites increased with the increase of nanoparticles in the enzymatic, soil and compost media. Besides, with the addition of cellulose nanocrystal and nanoclay to the polymer matrix, the overall migration of composites decreased. This could be due to a better adhesion of the nanoparticles to the polymer matrix, and the tortuousity of their path.

Cellulose nanocrystal is a functional material because of its properties like high specific surface ratio, high crystallinity, and good mechanical and optical properties. It has emerged as a new material class for advanced military products such as bulletproof vests, fire-resistant materials, propellants, and electronic products. In this study, high purity cellulose was extracted from sugar beet pulp by soda-anthraquinone pulping method and bleached to remove maximum hemicellulose and lignin. Then cellulose nanocrystal was produced from extracted cellulose with 64% sulfuric acid. The resulting crystalline nanocellulose was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA). Transmission electron microscopy analysis confirmed the presence of cellulose nanocrystal. Hydrolysis with concentrated sulfuric acid increased the crystallization of bleached cellulose and reduced its size to the nanoscale. The diameter of cellulose nanocrystal was less than 20 nm, the length was in the 200-400 nm range, and the production yield was 53%, which is comparable to cellulose nanocrystal from wood and other biomass sources. This product can be used in various military applications, including durable and lightweight composites, surfaces with anti-corrosion properties, and bandages.

In the present study, preparation of cotton stalk (Sahel variety) as one of the common agricultural residues was studied through three stages as Soda-AQ chemical pulping, delignification and alkaline treatment, aiming for the production of cellulose nanocrystal. In order to identify the optimum condition for the preparation of cellulose nanocrystal, acidic hydrolysis of the produced alpha-cellulose was done using 64% sulfuric acid, 25, 35 and 45 minute as time and at 35, 45 and 55oC as temperature. Atomic Force Microscopy (AFM), XRay Diffraction, and Dynamic Light Scattering (DLS) were used to identify the quantitative and qualitative properties of cellulose nanocrystals. AFM micrographs showed that more severe condition of the treatments decreased the thickness of the cellulose nanocrystals. XRD results also demonstrated that the preparation stages of alpha-cellulose as well as acidic hydrolysis treatments much effectively increased the degree of crystallinity. DLS results indicated that 98.7 percent of the produced nanocrystals under the condition of 55oC and 45 minute were in the range of 18-95 mm., whose highest abundance was in the range of 18-39 mm. Thus, the mentioned condition were determined as the best and optimum condition for the production of cellulose nanocrystal from cotton stalk cellulose.

Petroleum effluent treatment uses ultrafiltration nanocomposite membrane made of polysulfone and cellulose nanocrystal. In this study, nanocomposite membranes were synthesized by adding different amounts of cellulose nanocrystals (CNCs) to polysulfone membrane (PSF) in order to enhance the membrane's anti-fouling properties against the accumulation of oil particles and then synthesize the membrane properties by spectral analysis. Scanning electron microscopy (SEM), infrared spectroscopy FTIR and contact angle test (CA) were applied to investigate membrane morphology. The results showed that the porosity and hydrophilicity of PSF/NC composite membrane were significantly improved. Experiments related to the performance of the petroleum effluent ultrafiltration system have shown that nanocomposite membranes with 1% cellulose nanocrystals (CNCs) increase the water flux by 60%, excreting about 100% of the petroleum compounds, and optimally recovering the water flow to 94. 4%. The findings suggest that the newly developed nanocomposite membrane is an optimal choice for treatment of low concentrated oily wastewater.