RESUMEN
Hemp fiber (Cannabis sativa) is being widely used to produce carboxymethyl cellulose (CMC). This study focused on synthesizing carboxymethyl cellulose from bleached hemp fiber to investigate the impact of different factors, i.e., chemical concentration and synthesis time, on its characteristics. The fiber morphology analysis revealed desirable properties, which are essential for high-quality CMC production. Optimal condition for CMC synthesis were investigated, which involved using 20 % NaOH (w/v), the shortest total synthesis time (2.30h), and using 0.9 g MCA (w/w). This resulted in a non-significantly high DS (0.80) in both nonspray-dried and spray-dried hemp carboxymethyl cellulose, representing a high CMC content around 96 %. Moreover, the use of ultrasonic assistance and spray drying techniques significantly improved the hemp carboxymethyl cellulose properties, indicating a decreased molecular weight (2.65 × 104 g/mol) and a decreased particle size (7.82 µm). Thermal analysis revealed that spray-dried hemp carboxymethyl cellulose had lower thermal stability than hemp fiber and nonspray-dried hemp carboxymethyl cellulose. FTIR and 13C NMR analyses confirmed the successful CMC synthesis. Additionally, XRD and SEM analyses demonstrated changes in the crystalline structure and hemp carboxymethyl cellulose surface morphology. This revealed advanced techniques that could enhance hemp carboxymethyl cellulose quality and properties, making it suitable for various industrial applications.
RESUMEN
The objective of this study was to investigate the morphological and chemical properties of hemp bast RPF1 variety fiber to be used as a potential raw material for filter paper production. Experimental handsheet samples with basis weight of 20 g/m2 were manufactured using mixture of hemp and softwood pulp at various beating levels. The average fiber length and width of hemp bast fiber were determined as 5.76 mm and 32.53 µm, respectively. It was also found that the hemp bast fiber had rigid thick cell wall with small size of lumen. The overall chemical properties of hemp bast were similar to those fibers from other bast sources as well as softwood fibers. It seems that hemp bast was easily pulped under various soda process conditions yielding pulp ranging from 51.36 % to 52.56 % and Kappa numbers ranging from 2.89 to 8.18. Based on the findings in this study hemp bast fiber could be considered as a potential to manufacture filter paper with accepted characteristics.
RESUMEN
Bacterial cellulose (BC), prepared from two recently developed thermotolerant bacterial strains (Komagataeibacter xylinus C30 and Komagataeibacter oboediens R37-9), were used as a raw material to synthesize nanofibril films. Field-emission scanning electron microscope (FE-SEM) observations confirmed the ultrafine nano-structure of BC pellicle (BCP) with average fibril widths between 50 and 60 nm. The BC was directly oxidized in a TEMPO/NaBr/NaClO system at pH of 10 for 2 h. TEMPO-oxidized bacterial cellulose nanofibrils (TOBCN) were obtained by a mild mechanical treatment and the TOBCN films were prepared through heat-drying. The oxidation yielded a recovery ratio between 70 and 80% by weight with an increase in the carboxylate content of 0.9-1.0 mmol g -1. Nanofibrillation yields were more than 90% and the resulting high aspect ratio TOBCNs were ~6 nm in average width with >800 nm in lengths, when observed under transmission electron microscope (TEM). TOBCN film of K. xylinus C30 exhibited high transparency (79%), tensile strength (142 MPa), Young's modulus (7.13 GPa), elongation around failure (3.89%), and work of fracture (2.29 MJ m-3), when compared to the TOBCN films of K. oboediens R37-9 at 23 °C and 50% RH. Coefficients of thermal expansion of both the TOBCN films were low at around 6 ppm K-1.
