Yunhua Zhang

Cellulose nanofibers (CNFs) with high aspect ratio was prepared from wood cellulose using 2,2,6,6-tetramethylpiperidine oxygen radical (TEMPO) oxidation method. By UV, TEM, FT-IR, XRD and TG, the characterizations of CNFs were studied. The results showed that CNFs was a a hydrophilic natural nanomaterials with good suspension stability, high aspect ratio and cellulose I crystal structure. The modified double base propellant with high solid content prepared by calendering process was modified by using CNFs as nano-fillers. The results of tensile test and burning test of propellant showed that the mechanical properties and combustion performances of CNFs modified double base propellant had been improved significantly compared to conventional modified double base propellant. The tensile strength and elongation at break can be increased by nearly 34%, 45%,respectively. The burning rate of propellant can be increased by 27.5% while the pressure coefficient decreased by 20%.

This paper addresses a simple method to prepare antibacterial carboxymethyl cellulose (CMC)/polyoxyethylene(PEO) nanofiber mats containing silver nanoparticles (Ag NPs). The nanofibers are fabricated by electrospinning of CMC/PEO/AgNO₃ blend aqueous solution with an AgNO₃ concentration of 10mmol/L. In electrospinning procedure, Ag NPs with average diameter of 4.5 nm are obtained and separated from each other on the surface of CMC/PEO nanofibers. The nanofibers have smooth surface and narrow size distribution. The CMC/PEO/Ag NPs nanofiber mats show good antimicrobial activity against E. coli and photoluminescent performance, which can be applied in biomedicine such as wound dressings or anti-adhesion membranes.

Nitrocellulose (NC) alcogels were formed in NC/acetone/ethanol ternary system and NC aerogels were prepared from NC alcogels after drying under supercritical CO₂ (scCO2). NC alcogel with lower modulus was formed in the ternary system with a higher ethanol ratio. The densities and porosities of NC aerogels were related directly to the initial ethanol content. The NC aerogels clearly retained the crystalline structure of NC powder. NC aerogels that were formed in the system with higher ethanol content had larger pore size distribution range, larger average pore diameter, and larger mesopore and macropore volume. The thermal decomposition of NC aerogel was more accelerated and more acute compared with NC powders.

Nanoparticles have attracted a great deal of attention because of their broad range of application in biotechnology and nanomedicine. In this paper, magnetic-fluorescent nanoparticles based on iron oxide and biopolymer (chitosan and carboxymethyl cellulose) were fabricated. Using a layer-by-layer approach, two core-shell type architectures could be formed in the nanoparticles: (1) fluorescent groups placed in the outer layer or (2) with-in the layers consisting of cationic poly-electrolyte. Both of these particles showed superparamagnetic and strong fluorescent properties. The nanoparticles had higher encapsulation efficiency and pH-sensitive drug release over a long time.

Nitrate glycerol ether cellulose (NGEC) alcogels are formed in the ternary NGEC/acetone/ethanol system. NGEC aerogels are prepared from NGEC alcogels after solvent exchange and drying under supercritical CO₂ (scCO₂). The aerogels are prepared with various densities and porosities, relating directly to the initial ethanol content. NGEC aerogels had surface areas of up to 183 m² g⁻¹ and large mesopore volumes with a combination of large macropore volumes and a wide range of mesopore sizes. The aerogels with larger pore size distribution range, average pore diameter, and mesopore and macropore volume were obtained from system with higher ethanol content. The aerogels were further characterized by X‐ray diffraction, Brunauer–Emmett–Teller analysis, electron microscopy, and thermogravimetric analysis. The results showed that the NGEC aerogels clearly retained the crystalline structure from NGEC. Compared with NGEC powders, the thermal decomposition of NGEC aerogel is accelerated and this process becomes more acute. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41405.