Upon the Weissenberg Effect of Cellulose Acetate Solution.

Gelatin in fibers form can be used for tissue engineering, wound dressing, or drug carrier. However, it is easily damaged if exposed to water. Thus, it was blended with cellulose acetate. Acetic acid was used as a solvent because it is less toxic. The mass ratios of gelatin to cellulose acetate of 10:0, 8:2, and 6:4 were as precursor solutions. Simple electrospinning was employed to produce gelatin/cellulose acetate fibers. From SEM images, it was shown that the average diameters of gelatin/cellulose acetate fibers from the precursor solutions of 10:0, 8:2, and 6:4 were 534, 649, and 765 nm, respectively. The addition of cellulose acetate increased the viscosity of gelatin/cellulose acetate solution. Moreover, gelatin mass reduction caused a decrease in conductivity of gelatin/cellulose acetate solution. Therefore, increasing in the viscosity or reducing in the conductivity of the precursor solution increased the average diameter of the gelatin/cellulose acetate fibers. The analysis of FTIR spectra showed that the structural changes of gelatin and cellulose acetate occurred after being transformed into gelatin/cellulose acetate nanofibers.

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Comparison of Rosin and Propolis Antimicrobials in Cellulose Acetate Fibers Against Staphylococcus aureus

BioResources ◽

10.15376/biores.15.2.3756-3773 ◽

2020 ◽

Vol 15 (2) ◽

pp. 3756-3773

Keyword(s):

Staphylococcus Aureus ◽

Cellulose Acetate ◽

Dermal Fibroblast ◽

Quantitative Difference ◽

Antibacterial Properties ◽

Acetate Solution ◽

Solvent Type ◽

Colony Forming Units ◽

High Concentrations ◽

The Fourier Transform

The quantitative difference in the antibacterial response was measured for pine rosin and propolis against Staphylococcus aureus ATCC 12598. The activity was studied for fibrous networks that form entirely bio-based cellulose-acetate (CA) materials. The analysis considers the effects of bacterial input, additive dosage, solvent type, variation in preparation, as well as the effect of storage time. Based on the results, the electrospun network structure is dependent on the solvent and the concentration of rosin and propolis. Both rosin and propolis improved the cellulose acetate solution processability, yet they formed beads at high concentrations. Rosin and propolis created strong antibacterial properties when these material systems were immersed in the liquid for 24 h at room temperature. The response remained visible for a minimum of two months. The electrospun networks of water and DMAc solvent systems with 1 to 5 wt% rosin content were clearly more efficient (i.e., decrease of 4 to 6 logs in colony forming units per mL) than the propolis networks, even after two months. This efficiency is likely due to the high content of abietic acids present in the rosin, which is based on the Fourier transform infrared spectra. The results of the additional analysis and cell cultivation with dermal fibroblast cells indicated an impairing effect on skin tissue by the rosin at a 1 wt% concentration compared to the pure CA fibers.

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Filtration Performance of Ultrathin Electrospun Cellulose Acetate Filters Doped with TiO2 and Activated Charcoal

Buildings ◽

10.3390/buildings11110557 ◽

2021 ◽

Vol 11 (11) ◽

pp. 557

Author(s):

Roberta Orlando ◽

Yilun Gao ◽

Peter Fojan ◽

Jinhan Mo ◽

Alireza Afshari

Keyword(s):

Pressure Drop ◽

Cellulose Acetate ◽

Removal Efficiency ◽

Activated Charcoal ◽

Charged Particles ◽

Particle Sizes ◽

Acetate Solution ◽

Electrospun Fibre ◽

Filtration Performance ◽

Composite Filter

Air filters are crucial components of a building ventilation system that contribute to improving indoor air quality, but they are typically associated with relatively high pressure drops. The purpose of the study is to evaluate the effect of additives on ultrathin electrospun filters, the pressure drop, and the particle removal efficiency of uniformly charged particles. The fibres were electrospun under optimised conditions that resulted in a fast-fabricating process due to the properties of the cellulose acetate solution. Different ultrathin electrospun fibre filters based on cellulose acetate (CA) were fabricated: a pure CA electrospun fibre filter, two filters based on CA fibres separately doped with activated charcoal (AC) and titanium dioxide (TiO2), respectively, and a composite filter where the two additives, AC and TiO2, were embedded between two CA fibres layers. The ultrathin filters exhibited a low pressure drop of between 63.0 and 63.8 Pa at a face velocity of 0.8 m s−1. The filtration performance of uniformly charged particles showed a removal efficiency above 70% for particle sizes between 0.3 and 0.5 μm for all filters, rising above 90% for larger particles between 1 and 10 μm, which translates to the average sizes of pollens and other allergenic contaminant particles. Due to the positive impact on the fibre morphology caused by the additives, the composite filter showed the highest filtration performance among the produced filters, reaching 82.3% removal efficiency towards smaller particles and a removal of up to 100% for particle sizes between 5 and 10 μm. Furthermore, cellulose acetate itself is not a source of microparticles and is fully biodegradable compared to other polymers commonly used for filters. These ultrathin electrospun filters are expected to be practical in applications for better building environments.

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Uranium Carbide Fibers with Nano-Grains as Starting Materials for ISOL Targets

Nanomaterials ◽

10.3390/nano10122458 ◽

2020 ◽

Vol 10 (12) ◽

pp. 2458

Author(s):

Sanjib Chowdhury ◽

Leonor Maria ◽

Adelaide Cruz ◽

Dario Manara ◽

Olivier Dieste-Blanco ◽

...

Keyword(s):

Cellulose Acetate ◽

Uranyl Acetate ◽

Slow Heating ◽

Acetate Solution ◽

Fiber Morphology ◽

Uranium Carbide ◽

C Fibers ◽

Effective Contact ◽

Viscous Solutions ◽

Nano Grains

This paper presents an experimental study about the preparation, by electrospinning, of uranium carbide fibers with nanometric grain size. Viscous solutions of cellulose acetate and uranyl salts (acetate, acetylacetonate, and formate) on acetic acid and 2,4-pentanedione, adjusted to three different polymer concentrations, 10, 12.5, and 15 weight %, were used for electrospinning. Good quality precursor fibers were obtained from solutions with a 15% cellulose acetate concentration, the best ones being produced from the uranyl acetate solution. As-spun precursor fibers were then decomposed by slow heating until 823 K under argon, resulting in a mixture of nano-grained UO2 and C fibers. A last carboreduction was then carried out under vacuum at 2073 K for 2 h. The final material displayed UC2−y as the major phase, with grain sizes in the 4 nm–10 nm range. UO2+x was still present in moderate concentrations (~30 vol.%). This is due to uncomplete carboreduction that can be explained by the fiber morphology, limiting the effective contact between C and UO2 grains.

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