E-mail: ylhsieh@ucdavis.edu.SynopsisHighly thermal-stable CNFs were defibrillated at high yields with ACC treatment of rice straw and assembled into submicron fibers and translucent films.AbstractRice straw cellulose was completely defibrillated via aqueous counter collision (ACC) at a low energy input of 15 kWh/kg, then fractionated by differential centrifugation into four increasing weight fractions of progressively thinner cellulose nanofibrils (CNFs): 6.9% in 80–200 nm, 14.4% in 20–80 nm, 20.3% in 5–20 nm, and 58.4% in less than 5 nm thickness. The 93.1% less than 80 nm or 78.7% less than 20 nm thick CNFs yields were more than double those from wood pulp by other mechanical means but at a lower energy input. The smallest (3.7 nm thick and 5.5 nm wide) CNFs were only a third or less in lateral dimensions than those obatined through ACC processed from wood pulp, bamboo, and microbial cellulose pellicle. The less than 20 nm thick CNFs could self-assemble into continuous submicron (136 nm) wide fibers by freezing and freeze-drying or semitransparent (13–42% optical transmittance) film by ultrafiltration and air-drying with excellent mechanical properties (164 MPa tensile strength, 4 GPa Young’s modulus, and 16% strain at break).

ACC defibrillated CNFs retained essentially the same chemical and crystalline structures and thermal stability as the original rice straw cellulose and therefore were much more thermally stable than TEMPO oxidized CNFs and sulfuric acid hydrolyzed cellulose nanocrystals from the same rice straw cellulose.Keywords: Aqueous counter collisionCellulose nanofibrilsDifferential centrifugationRice strawSelf-assemblingView: ACS ActiveView PDF | air purifier 600 model # wh10600Collagen, a prominent biopolymer, which is famous for its excellent biological activity, has been used extensively for tissue engineering applications. alen a350 energy star hepa air purifier reviewsIn this study, a novel solvent system for collagen was developed with an ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]), solvent system. honeywell air purifier 18155 manual

A series of sodium salts were introduced into this solvent system to enhance collagen's dissolution procedure. The results show that the solubility of collagen was significantly influenced by the temperature and sodium salts. The solubility reached up to approximately 11% in the [EMIM][Ac]/Na2HPO4 system at 45°C. However, the structure of the regenerated collagen (Col-regenerated) may have been damaged. Hence, we focused on the structural integrity of the collagen regenerated from the [EMIM][Ac] solvent system by the methods of sodium dodecyl sulfate–polyacrylamide gel electrophoresis, Fourier transform infrared spectroscopy, ultrasensitive differential scanning calorimetry, atomic force microscopy, X-ray diffraction, and circular dichroism because its signature biological and physicochemical properties were based on its structural integrity. Meanwhile, a possible dissolution mechanism was proposed. The results show that the triple-helical structure of collagen regenerated from the [EMIM][Ac] solvent system below 35°C was retained to a large extent.