PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 4, Number 2, 2018
immobilized cellulase exhibited broader temperature stability than in the free form. Additionally, immobilized cellulase gel disks can be easily separated and reused with great reusability capacity of about 85% of the initial activity after six cycles. Immobilized cellulase was capable to disintegrate cellulose fibres providing nanofibres with diameter of 15 –35 nm and several micrometres long. Overall, enhanced thermal stability and reusability of immobilized cellulase pave the way for its use in industrial production of CNF that can be applicable for biomedical and food packaging applications. Preparation and properties of microfibrillated cellulose with different carboxyethyl content, Jing-Huan Chen et al, Carbohydrate Polymers, Vol.206. Carboxyethyl reaction was used as a pretreatment method before grinding and homogenization to prepare microfibrillated cellulose (MFC). The effect of carboxyethylation on the properties of cellulose materials and prepared MFC samples were investigated. Results showed that cellulose materials with different carboxyethyl content were obtained by controlling the chemical dosage. This reaction increased the water retention value, decreased the degree of polymerization and crystallinity, and changed the crystalline structure of cellulose. This study provides a comprehensive understanding of carboxyethyl pretreatment for the preparation of MFC, which may help to enrich and promote the preparation and application of MFC. Nanoparticles capture on cellulose nanofiber depth filters, Houssine Sehaqui et al, Carbohydrate Polymers , online. A self-standing filter with a porosity of 80% is prepared from naturally abundant cellulose biopolymer in its native state by water-based cationization and freeze-drying processes. The positive surface charge of the filter in a wide pH range favours its interaction with various nanoparticles (NPs), while its tortuous sheet structure builds a contact between cellulose nanofibres (CNF) and the NPs, and hinders them to pass through the filter. Unlike membranes used for the retention of NPs and viruses, the separation in the CNF filter is not only limited to its surface but occurs also in its interior even when the NPs are orders of magnitude smaller than the filter pores. The present filter concept may not only address shortcomings of the current membrane systems, but could offer a disruptive technology for the sustainable and universal water purification. Eco-friendly Modification of a Regenerated Cellulose Based Film by Silicon, Carbon and N-doped Carbon Quantum Dots, Cuevas, B.B. et al, Carbohydrate Polymers , online. Modification of a regenerated cellulose thin film by inclusion of different non-toxic nanodots (silicon-dots (SiDs), carbon-dots (CDs) or nitrogen-doped carbon dots (N-CDs)) by aqueous nanodots solution immersion was performed. Our results reveal that the inclusion of the different nanodots in the cellulosic support increases, in different percentages, the mechanical resistance and electrical conductivity, but they hardly affect the transmittance of the original film. In fact, the non-toxic character of both support film and nanodots, endorses the use the use of these new nano-engineering films in biomedical applications. Recyclable deep eutectic solvent for the production of cationic nanocelluloses, Panpan Li et al, Carbohydrate Polymers , online. Deep eutectic solvents (DESs) are potential green systems that can be used as reagents, extraction agents and reaction media. DESs are often biodegradable, easy to prepare and have low toxicity. In this work, a recyclable DES formed from aminoguanidine hydrochloride and glycerol (AhG) was used as a reaction medium and reagent (aminoguanidine hydrochloride) for the production of cationic nanocelluloses.
Technical Abstracts
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