Preparation Of Cellulose Acetate Research Articles

Preparation and characterization of porous polyethersulfone (PES) membranes with improved biocompatibility by blending sulfonated polyethersulfone (SPES) and cellulose acetate (CA) – A comparative study

The current study focuses on the effective sulfonation of polyethersulfone (PES) polymer to synthesize sulfonated-polyethersulfone (SPES) and blending with PES to prepare SPES/PES blend membranes as well as preparation of cellulose acetate CA/PES blend membranes. FTIR-ATR technique was used to confirm the blending of SPES and CA into PES matrix. Water contact angle studies showed a significant reduction of hydrophobicity in SPES blend membranes (49.55 ± 1.52°) as compared with CA blend membranes (59.42 ± 2.20°) and PES base membranes (67.80 ± 1.48°). The presence of pores were analysed using scanning electron microscopy (SEM) where significant changes in the membrane morphology in the blend membranes were observed. Platelet adhesion, protein adsorption and activated partial thromboplastin time (APTT) studies were used to assess hemocompatibility of the membranes in which SPES/PES membranes exhibited improved characteristics as compared with its counterparts. The cytocompatibility of membranes were evaluated using water soluble tetrazolium (WST) assay which confirmed that both SPES/PES and CA/PES blend membranes exhibit better cytocompatibility than base PES membrane

Preparation and Characterization of Cellulose Acetate from Pineapple (<i>Ananas comosus</i>) Leaves

Pineapple leaves was utilized for the fabrication of cellulose acetate. It underwent a series of process that includes alkaline treatment using sodium hydroxide aqueous solution, bleaching treatment using acetate buffer and aqueous sodium chlorite, and acetylation using acetic anhydride. The preparation of cellulose acetate was done in different acetylation times (8, 16, 24 and 32 hours). The cellulose acetate samples were then characterized using fourier transform infrared spectroscopy (FTIR) to elucidate the vibrational move, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) to investigate the thermal property of the material and scanning electron microscopy (SEM) to examine the surface morphology. FTIR result showed significant decrease in absorption intensity of the O-H stretch after the acetylation which indicates the substitution of hydroxyl group by acetyl group. On the other hand, the emergence of C=O stretch of the ester group and C-O stretch of acetyl group can be observed which indicates the formation of cellulose acetate. TGA and DTA also shows enhanced thermal stability of cellulose acetate prepared in 16 hrs acetylation period. Increasing the reaction time to 24 hrs and 32 hrs resulted to significant decrease in thermal stability. SEM images revealed the deterioration on the physical structure of cellulose after 24 hrs acetylation.

Preparation of TiO<sub>2</sub>/WO<sub>3</sub> Composite Nanofibers by Electrospinning

Preparation of cellulose acetate (CA)/TiO2/WO3 composite nanofibers via sol-gel with electrospinning process for improving the photocatalytic efficiency was conducted. CA was removed from fibers by a heat treatment. Microstructure and elemental composition of TiO2/WO3 nanofibers were evaluated by scanning electron microscope (SEM) and energy dispersive microscopy (EDX), respectively. The results showed that the nanofibers of TiO2 and WO3 were achieved with the average diameter range of ca. 310-701 nm and both TiO2 and WO3 are well dispersed along fiber length, confirmed by an EDX analysis. The results also showed that the smoothness of fiber surface decreased with decreasing WO3 contents. The photocatalytic activity of the materials were also tested for methylene blue degradation. TiO2/WO3 exhibited the highest activity comparing to pure TiO2 and WO3. Moreover, it was found that a TiO2/WO3 specimen possessed the energy storage ability as a result, it showed the photocatalytic activity in the absence of light.

Preparation and Characterization of Coaxial Electrospun Fibers Containing Triclosan for Comparative Study of Release Properties with Amoxicillin and Epicatechin.

The optimal conditions for the fibers preparation of cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP) containing triclosan within the fiber were successfully found; the physicochemical characteristics of these fibrous membranes were corroborated by FTIR spectroscopy, thermal analysis, mechanical tests, SEM , and TEM analysis. The formation of composite fibers of CA and PVP containing triclosan at the core of the fiber was evidenced. A comparative study of the release properties of amoxicillin, epicatechin or triclosan embedded into fibers CA/PVP/CA was performed. As more interactions of the drug with CA or PVP occur, slower release of the drug into the release medium takes place. Regarding the drug delivery system design, it is important to consider the possible molecular interactions between the material components and predict how fast or slow the drug will be delivered into the corresponding medium.

Preparation of Cellulose Acetate Ultra-Fine Fibers Containing Quasi-Spherical Gold Nanoparticles by Electrospinning Method

Quasi-spherical gold nanoparticles(Au NPs) prepared by trisodium citrate reduction of HAuCl4were dispersed into cellulose acetate(CA) ultra-fine fibers by electrospinning. The optical properties of Au NPs before and after electrospinning were measured by UV-vis spectrometer. The morphology and distribution of Au NPs in CA ultra-fine fibers were observed by transmission electron microscopy (TEM). The morphology and diameter of Au NPs/CA fibers were studied by scanning electron microscopy (SEM). The crystallinity change of CA fiber before and after adding Au NPs was characterized by X-ray diffraction (XRD).

Development, characterization and separation performance of organic–inorganic membranes: Part II. Effect of additives

The effects polyethylene glycol 600 (PEG 600) and lithium chloride (LiCl) as additives on the preparation of cellulose acetate (CA) and silica (SiO 2) blend ultrafiltration membranes were investigated in terms of water content, hydraulic membrane resistance, permeation performance, membrane morphology, and mechanical property. The addition of the additives into the casting solution changed the structure of the resultant membranes, which was believed to be associated with the change of the thermodynamic and kinetic properties of the system in the phase inversion technique. The pure water flux (PWF) of the membranes improved from 29.60 to 34.28 l m −2 h −1 when 5 wt.% LiCl and PEG was used as the additives in the pure CA membrane, respectively. The average pore size and porosity of the membranes were revealed by pore statistics and molecular weight cut-off (MWCO) studies using different molecular weight of proteins. Among the two additives, the membrane made from the casting containing PEG possessed the highest average pore size and porosity. The separation of proteins with the membranes was also studied. In particular, it was found that CA/SiO 2 blend membranes with additives exhibit improved permeate flux of proteins. The fouling-resistant ability and the recycling potential of the UF membranes were found using bovine serum albumin (BSA) as model protein and the results are discussed. The results indicated that presence of pore formers (PEG and LiCl) in pure CA and all composition CA/SiO 2 blend membrane, the total fouling resistance decreased resulting in enhanced flux recovery ratio which improved the life time membranes.

Effect of casting solvent and polymer on permeability of propranolol hydrochloride through membrane controlled transdermal drug delivery system

In the present work, cellulose acetate and ethyl cellulose films were prepared and evaluated as rate controlling membrane for transdermal drug delivery systems. In each case films were prepared using solutions of the polymer in various solvents to evaluate the influence of the solvent used on the mechanical and permeability properties of the films. Acetone-methanol (8:2), chloroform-methanol (8:2), dichloromethane-methanol (8:2) and ethyl acetate-methanol (8:2) were used as solvents in the preparation of cellulose acetate and ethyl cellulose films. Dibutyl phthalate or propylene glycol at a concentration of 40% w/w of the polymer was used as a plasticizer in the preparation films. The method of moulding was found to be giving thin uniform films. The dry films were evaluated for physical appearance, thickness uniformity, folding endurance, water vapour transmission, drug diffusion and permeability coefficient. Both water vapour transmission and Drug diffusion rate followed zero order kinetics. The mechanism of drug release was governed by Peppas model. The diffusion exponent of release profiles (slope) has a value of 1.0360-1.3147 (n>1), which indicates non anomalous transport diffusion. The results obtained in the present study thus indicated that the polymers and solvents used in the preparation of films have shown significant influence on the water vapour transmission, drug diffusion and permeability of the films. Area of patches ranging from 1.29- 4.53 cm 2 were found to yield the desired release rate of propranolol hydrochloride. Cellulose acetate films employed with ethyl acetate:methanol in 8:2 ratio as casting solvent yielded low area (1.29 cm 2 ) of patch with desired release rate.

Acetylation of Bacterial Cellulose: Preparation of Cellulose Acetate Having a High Degree of Polymerization.

Cellulose triacetate prepared from bacterial cellulose of Acetobacter xylinum subsp. sucrofermentans BPR3001A showed a higher degree of polymerization and higher mechanical strength than that from the cotton linter. The fine fibrils of bacterial cellulose required only a short time for acetylation which preserved the high degree of polymerization.

Preparation of Cellulose Acetate - Action of Sulfuric Acid

Preparation of Cellulose Acetate - Action of Sulfuric Acid

New Method of Sound Recording

FOR many years past it has been the practice with broadcasting organisations to record sound programmes for reproduction as and when required. In some cases this technique makes use of ordinary gramophone records or of metal disks coated with a preparation of cellulose acetate. In other cases, the sound programme to be recorded is made to influence the longitudinal magnetization of a continuous steel tape which passes under the recording head. This latter process is suitable for long programmes, which can either be reproduced immediately or after an interval, the tape being rewound and passed under a suitable magnetic pick-up. The recording can afterwards be effaced or 'wiped off' the steel tape by a demagnetization or saturation process, and the tape can thus be used many times for different programmes.

醋酸纎維素製造試驗

醋酸纎維素製造試驗