Preparation and Characterization of Cellulose Acetate Film Reinforced with Cellulose Nanofibril

In this study, cellulose acetate (CA)/cellulose nanofibril (CNF) film was prepared via solvent casting. CNF was used as reinforcement to increase tensile properties of CA film. CNF ratio was varied into 3, 5, and 10 phr (parts per hundred rubbers). Triacetin (TA) and triethyl citrate (TC) were used as two different eco-friendly plasticizers. Two different types of solvent, which are acetone and N-methyl-2-pyrrolidone (NMP), were also used. CA/CNF film was prepared by mixing CA and CNF in acetone or NMP with 10% concentration and stirred for 24 h. Then, the solution was cast in a polytetrafluoroethylene (PTFE) dish followed by solvent evaporation for 12 h at room temperature for acetone and 24 h at 80 °C in an oven dryer for NMP. The effect of solvent type, plasticizers type, and CNF amount on film properties was studied. Good dispersion in NMP was evident from the morphological study of fractured surface and visible light transmittance. The results showed that CNF has a better dispersion in NMP which leads to a significant increase in tensile strength and elastic modulus up to 38% and 65%, respectively, compared with those of neat CA. CNF addition up to 5 phr loading increased the mechanical properties of the film composites.

Improvement of stability for cellulose polymer by calcium oxide for application to porous materials

In this study, calcium oxide (CaO) was used as an additive to form pores in a cellulose acetate (CA) membrane and at the same time improve the thermal stability of the cellulose acetate membrane. When the CA/CaO membrane was exposed to water pressure, the solvent was removed from the CA matrix area plasticized by the CaO particle size and water channels were formed. In addition, the high melting point of CaO and its bonding with the carbonyl group of CA caused a crosslinking effect. We succeeded in membrane synthesis with a high porosity of 73.1% and flux data of 95.25 L/m2h at 8 bar, which was enhanced thermally with an increased decomposition temperature of 50°C on thermogravimetric analysis (TGA). The pores generated in the cellulose acetate film were confirmed using a scanning electron microscope machine (SEM) and mercury porosimeter. Thermal stability and interactions in materials were measured using TGA and Fourier transform infrared (FT-IR).

One-Step Synthesis of Eu3+-Modified Cellulose Acetate Film and Light Conversion Mechanism

A CA-Eu(III) complex was synthesized by the coordination reaction of cellulose acetate (CA) and Eu3+ to obtain a CA-Eu light conversion film. This product was then doped with Tb(III) to sensitize the luminescence of Eu3+, which could functionalize the CA film. FTIR and XPS showed that the oxygen atoms in C=O, C–O (O=C–O), and O–H were involved in the complexation with Eu3+ and formed a Eu–O bond. SEM revealed that Eu3+ filled in the pores of the CA film. By changing the experimental conditions, the best fluorescence performance was obtained at the CA: Eu3+ ratio of 3:1 with a reaction time of 65 min. The energy transfer between Tb3+–Eu3+ could be realized by doping Tb3+ to enhance the luminescence of Eu3+. The best fluorescence performance of the CA-Eu-Tb light conversion film was at a Eu3+:Tb3+ ratio of 3:1. Compared with the CA film, the light conversion film has high transparency, high tensile strength, and good flexibility. It can convert the ultraviolet light harmful to plants into red light that is beneficial to photosynthesis. This offers high efficiency and environmental protection in the field of agricultural films.

Effect of water compounds on photo-disinfection efficacy of TiO2 NP-embedded cellulose acetate film in natural water

Photocatalysis disinfection has great potential for irrigation water disinfection to improve fresh produce safety. Titanium dioxide (TiO2) nanoparticle (NP)-embedded cellulose acetate (CA) film has shown effectiveness against Escherichia coli (E. coli) O157:H7 in water. The current study evaluated the effect of natural water compounds on the photo-disinfection efficacy of TiO2 NP-embedded CA film. Humic acid, calcium carbonate (CaCO3), and kaolin clay solutions were prepared at four concentrations, respectively. When concentration increased from 0 to 20 ml/L, inactivation of E. coli O157:H7 in humic acid, CaCO3, and kaolin clay solutions decreased from 6 log to 5, 4, and 2 log CFU/ml, respectively after 3 h treatment. Turbidity, UVT-254, water hardness, total suspended solids (TSS), and total organic carbon (TOC) of the solutions were measured. UVT-254 and turbidity had the highest correlation with the inhibition effect of water compounds on photo-disinfection efficacy. A prediction equation was developed with UVT-254 and water hardness as independent variables to predict photo-disinfection efficacy in natural water. E. coli O157:H7 decreased by 1 and 2.5 log CFU/ml in unfiltered and filtered natural creek water samples after treatment. The results from this study showed promise in the use of TiO2 NP-embedded CA film to inactivate pathogens in natural water.