Interfacial Interaction Between Polyurethane/Poly(Methacrylateco-Styrene) Coating and the Regenerated Cellulose Film

Water-resistant films were prepared by coating the surface of regenerated cellulose films with castor oil-based polyurethane (PU)/ poly-(methacrylate-co-styrene) [P (MA-St)]. The effects of the ratio of PU to P (MA-St) copolymer on tensile strength (dry and wet states), vapor permeability, size stability, and water resistivity of the coated films were studied. The interfacial interaction between cellulose and the PU/P (MA-St) coating was analyzed using infrared (IR), ultraviolet (UV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal analysis (DTA), and electron probe microanalysis (EPMA). The results indicated that the mechanical properties and water resistivity of the coated films significantly enhanced, and the biodegradability was displayed, when the ratio of PU to P (MA-St) was 8∶2 by weight. The chemical bonds and hydrogen bonds between the cellulose, PU, and the copolymer exist in the coated films. It is regarded that PU/P (MA-St) semi-interpenetrating polymer networks (IPNs) were formed, and a shared network of PU with both the cellulose and the coating in the coated film occurred simultaneously resulting in a strong bonding between the coating layer and the film.

Effect of Thermal Treatment on the Properties of TEMPO Oxidized Cellulose Film for the Flexible Substrate of Solar Cell

The 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)oxidized cellulose film(TOCF)has been attempted to be used as a substrate in electronic and optoelectronic devices,but the changes in the TOCF properties before and after annealing treatment have usually been neglected during device fabrication.In this study,TOCF was treated in different atmospheres(air,vacuum,and N2)and at different temperatures,and the properties were investigated.The results indicate that the optical properties are slightly affected by atmosphere and temperature;only slight transmittance loss and haze increase have been observed when TOCF is exposed to an air atmosphere at temperatures of above 120℃.In contrast to the slight effects on the optical properties,cellulose degradation and a loss of film strength have been observed regardless of the atmosphere used when placed at temperatures of above 100℃.Specifically,TOCF was exposed to air,followed by N2 and vacuum atmospheres.Additional Fourier transform infrared(FT-IR)and nuclear magnetic resonance(NMR)results showed that increasing the temperature had no significant effect on the structure of TOCF.Therefore,the annealing temperature should be controlled at a temperature of lower than 100℃and a vacuum atmosphere is preferred.

STUDIES ON TUNG OIL COATED REGENERATED CELLULOSE FILMS WITH WATERRESISTANCE

Regenerated cellulose films with water-resistance were obtained by an improved method ofpreparing cellulose cuoxam solution from pulps of agricultural wastes (linters, wheat straw, reedand Bamao). Experimental results showed that the mechanical properties of both the dry. and wetfilms were excellent. Data from IR, SEM and tensile strength measurements implied that thesignificant improvement of water-resistance of the films was due to the cohesion between the thinTung oil covers with hydrophobicity and the regenerated cellulose films. The films werecompletely biodegraded after being buried in soil for 100 days. The transmittance of the filmsderived from linter and reed in visible band range were 80-90%.

BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose, glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water. After a month, the films were completely decomposed by fungi in the media at 30 degrees C.

Nanofibrillation of Bacterial Cellulose Using High-Pressure Homogenization and Its Films Characteristics

The microstructure of bacterial cellulose nanofibers(BCNs)film affects its characteristic.One of several means to engineer the microstructure is by changing the BCNs size and fiber distribution through a high-pressure homogenizer(HPH)process.This research aimed to find out the effects of repetition cycles on HPH process towards BCNs film characteristics.To prepare BCNs films,a pellicle from the fermentation of pineapple peels waste with Acetobacter xylinum(A.xylinum)was extracted,followed by crushing the pellicle with a high-speed blender,thereafter,homogenized using HPH at 150 bar pressure with variations of 5,10,15,and 20 cycles.The BCNs films were then formed through the casting process and drying in the oven at 60°C for 8 h followed by structural,morphological,and optical properties investigation using X-ray diffraction(XRD),scanning electron microscopy(SEM)and Fourier transform infrared(FTIR)spectrometer along with BCNs films porosity,tensile and roughness test.The research showed that the effect of HPH cycle on BCNs resulted in the highest film tensile strength by 109.15 MPa with the lowest surface roughness(Ra)of 0.93±0.10μm at 10 cycles.The HPH process is effective in controlling BCNs film porosity level.The HPH cycles influence the crystalline index and crystallite size,slightly.

Preparation and physicochemical/antimicrobial characteristics of asparagus cellulose

Due to the increased potential for application of natural biopolymers in the food industry,the goal of this study was to prospectively produce antimicrobial films using asparagus residue.In this study,cellulose was extracted from asparagus residue,and then 3 cellulose solutions of 0.008,0.01 and 0.025 g/mL were applied to prepare films using a phase inversion process.Films were characterized by Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),thermal gravimetric analysis(TGA)and scanning electron microscopy(SEM).The film produced by 0.01 g/mL asparagus cellulose solution exhibited a swelling ratio of 125.4%and excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus using the disk agar diffusion method.This study presents a promising method for producing antimicrobial films with asparagus residue.

Preparation and characterization of SiO_2/TiO_2/methylcellulose hybrid thick films for optical waveguides

SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 °C for an hour, 2.5-μm crack-free and dense organic-inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.

High Strength Cellulose Composite Films Reinforced with Clay for Applications as Antibacterial Materials

High strength cellulose composite films with antibacterial activities were prepared by dispersing montmorillonites （MMT） into cellulose solution in LiOH/urea aqueous solvent followed by regeneration in ethanol coagulation bath, and then by soaking in 5 wt% hexadecylpyridine bromide ethanol solutions to induce the antibacterial action. The cellulose/MMT composite films were characterized by field emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, FTIR, UV-spectra, wide angle X-ray diffraction and mechanical test. The results revealed that MMT was dispersed well in the cellulose matrix to form layer structure with a thickness of approximately 3 nm. The mechanical properties of the cellulose/MMT composite films were significantly improved to achieve 132 MP for tensile strength as a result of the MMT delamination. The hexadecylpyridine bromide was fixed well in the cellulose/MMT matrix through cation exchange, leading to the excellent antibacterial activities against Staphylococcus aureus and Escherichia coli, which is important in their practical applications.

Preparation and characterization of La_(0.8)Sr_(0.04)Ca_(0.16)Co_(0.6)Fe_(0.4)O_(3-δ)-La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_3 composite cathode thin film for SOFC by slurry spin coating

The La0.8Sr0.04Ca0.16Co0.6Fe0.4O3-δ (LSCCoF) and La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) powders were synthesized by glycine-nitrate combustion process and conventional solid-state reaction method, respectively. The LSCCoF-LSGM composite cathode material was successfully elaborated and deposited on dense pellets of the LSGM electrolyte by means of slurry spin-coating process. The cathode films with the best surface morphology and microstructure were obtained when the operating parameters fixed as follows: the content of ethyl cellulose which acted as pore former and binder is 10 wt.%, the content of terpineol which acted as modifier is 5 wt.%, the speed of rotation rate is 3200 r/min and the best post-deposition sintering temperature is 1000°C.