Shunxi Song

A promising transparent and UV-shielding composite film prepared by aramid nanofibers and nanofibrillated cellulose

An aramid nanofibers (ANFs)-functionalized nanofibrillated cellulose (NFC) composite film is effectively fabricated by the incorporation of ANFs into nanocellulose matrix. The fabrication of the composite film imitates the traditional paper-making process after homogenous mixing. The as-prepared composite film shows excellent UV-shielding performance due to the incorporation of ANFs. Thus the effect of ANFs contents is evaluated in aspects of the surface morphology, physicochemical properties including crystallinity, chemical structure and photothermal stability of composite film. Results show that the composite film with 2 wt.% of ANFs has improved mechanical properties, surface wettability compared to pure NFC film, and presents excellent UV-shielding performance ranging up to 400 nm while still retaining its high transparency. Moreover, the composite film shows high photostability even after continuous UV irradiation (365 nm) for over 12 h. The findings in the present work indicate that the ANFs-functionalized NFC composite films are promising as UV-shielding and transparent materials.

Design of double-component metal–organic framework air filters with PM2.5 capture, gas adsorption and antibacterial capacities

A biodegradable cellulose-based air filter (Ag-MOFs@CNF@ZIF-8) with multi-layer structure was fabricated by in situ generation of double-component metal-organic frameworks (MOFs) and reinforcement of cellulose nanofiber (CNF). It exhibits good filtration performance, gas adsorption, antibacterial activity and mechanical property. The presence of MOFs could enhance the interaction between the filter and particulate matter (PM) and significantly improve the specific surface area of the composite filter. Thus, the filtration efficiency of the composite filter could reach 94.3% for PM2.5 and the nitrogen adsorption capacity increased to 109 cm3 g-1. Furthermore, the Ag-MOFs@CNF@ZIF-8 filter exhibited excellent antibacterial activity against Escherichia coli with an inhibition zone diameter of 18.1 mm. The compressive strength of the composite filter could be up to 501 kPa, approximately 3.8 times higher than that of pure cellulose filter. Herein, this composite filter has a great application potential in PM2.5 removal, toxic gas adsorption and healthcare fields.

Engineered porous calcium silicate as paper filler: effect of filler morphology on paper properties

Abstract Developing engineered filler with special morphology to increase filler content and deliver paper desirable properties has been deserved much concern. In this work, two engineered calcium silicate fillers with different morphology, namely fly ash based calcium silicate (FACS), fibrous calcium silicate (FCS) were adopted to investigate the effect of filler morphology on paper properties, and natural wollastonite was used for comparison. It is found that FACS exhibits a wrinkled, porous surface while FCS reveals spherical agglomerates composed of needle-like particles. Physical tests demonstrated that in comparison with natural wollastonite with discrete shape, the aggregated porous structure of FACS and FCS showed noticeable improvement in bulk and opacity due to their high specific surface area (112 m2/g v.s 29 m2/g). At around 40 % filler content, the bulk of FACS and FCS filled handsheets increased 59.6 % and 43.8 %, respectively. The findings suggested that the engineered porous calcium silicate can be potentially used as paper filler in light weighted paper.

Highly improved mechanical and dielectric properties of paper-based composites with polyimide chopped fiber functionalized by ethylenediamine

In this study, polyimide (PI) chopped fibers were modified by ethylenediamine, and PI paper-based composites were fabricated using the as-modified PI chopped fibers and para-aramid fibrids which served as raw materials through the wet-forming process. The influence of different alkali treatment durations on the properties of PI fibers and composites was investigated. In sharp contrast with the pristine PI fibers, there was a satisfying difference in modified PI fibers including rougher surfaces and improved wettability due to the introduction of hydrophilic groups as confirmed by scanning electron microscope and Fourier transform infrared spectrometer. With increase in the modification time, the tensile index, the tearing index, and the internal bond strength of the composites were improved by 40.6, 27.0, and 103.57%, respectively, due to the hydrogen bonds. Meanwhile, the dielectric strength of the composites increased by 77.2% compared with the unmodified ones. These remarkable changes were mainly attributed to the enhanced interfacial bonding of the composites and decreased porosity in the three-dimensional network structure of the paper. Moreover, thermal stability was kept preferably within a certain range in spite of slight decrease.