نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکتری صنایع سلولزی، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
2 دانشآموخته دکتری تکنولوژی و مهندسی چوب، ،دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
3 استاد،گروه تکنولوژی و مهندسی چوب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.
4 دانشیار، گروه تکنولوژی و مهندسی چوب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Abstract
Background and objectives: Cellulose nanofibers (CNF) possess remarkable properties, including high mechanical strength, a vast specific surface area, and inherent characteristics of being bio-based, biocompatible, and biodegradable. These attributes position CNF as a material with significant potential for widespread application across diverse industries. These sectors span from construction, automotive, and electronics to air, water, and gas filtration, paper and packaging, textiles, sporting goods, medicine and biomedical engineering, the food industry, paints and coatings, aerospace, and beyond. However, existing production methods for this valuable nanomaterial have traditionally been wet-based. This results in the initial nanomaterial being produced and supplied with a very high water content, often as much as 98%. The conventional supply of CNF as a low-concentration aqueous suspension or gel presents considerable logistical challenges. These include significantly high transportation and storage costs, as well as the inherent risk of microbial degradation during storage. Consequently, drying emerges as an ideal solution to overcome these practical hurdles. Nevertheless, conventional and typical thermal drying processes often lead to an irreversible phenomenon known as hornification. This process involves the formation of permanent hydrogen bonds between the cellulose nanofibers, resulting in a loss of their redispersibility in water. To address and overcome this critical limitation, this research was undertaken with the specific aim of developing a dry, redispersible form of nanocellulose through the strategic addition of carboxymethyl cellulose (CMC).
Materials and Methods: The materials used in this research included cellulose nanofiber gel supplied by NanoNovin Polymer (knowledge-based company, Iran) and carboxymethyl cellulose (CMC) obtained from Dr. Mojalli Co. The CNF suspension or gel was mixed with varying amounts of CMC (1%, 2%, 3%, 5%, 10%, and 15%), and the mixtures were dried in a conventional oven at 70 °C. The redispersibility of the dried CNF powders in water and the physicochemical properties of the reconstituted gels were evaluated and compared with those of the never-dried CNF (control sample) through rheological measurements, FTIR spectroscopy, XRD analysis, FE-SEM imaging, and tensile testing.
Results: The results demonstrated that the presence of CMC effectively prevented irreversible hornification and enabled complete redispersion of CNFs in water. The sample containing 2% CMC (CNF2%) was identified as the optimal formulation, as its viscosity and tensile strength showed no statistically significant difference from the control sample, while FE-SEM images confirmed a uniform distribution with minimal fiber aggregation. FTIR and XRD analyses further indicated no undesirable chemical modifications or degradation of cellulose crystallinity. This research presents a practical, cost-effective, and scalable approach for producing dry cellulose nanofibers, offering a promising route to mitigate logistical challenges and facilitate the industrial utilization of this valuable nanomaterial.
Keywords: Cellulose nanofibers (CNF); Carboxymethyl cellulose (CMC); Thermal drying; Redispersion
کلیدواژهها [English]
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