scholarly journals Study on the Preparation of Cellulose Acetate Separation Membrane and New Adjusting Method of Pore Size

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 9
Author(s):  
Jianming Wang ◽  
Hongchen Song ◽  
Longfei Ren ◽  
Md Eman Talukder ◽  
Shunquan Chen ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Pore Size ◽  
Cellulose Acetate ◽  
Great Influence ◽  
Solid Content ◽  
Membrane Preparation ◽  
Solvent Ratio ◽  
Evaporation Time ◽  
Preparation Conditions ◽  
Separation Membrane

As a kind of eco-friendly (biodegradable) material and with a natural anti-fouling ability, cellulose acetate (CA) is more suitable for single-use membrane (especially in bioprocess). In this study, the method for preparing CA membrane by Vapor-assisted Nonsolvent Induced Phase Separation (VNIPS) was studied. The influences of ratio compositions (solid content, acetone/N,N-Dimethylacetamide ratio, glycerol/CA ratio) and membrane preparation conditions (evaporation time, evaporation temperature and humidity) on the microstructure and other properties were systematically evaluated. Results indicated that acetone/N,N-Dimethylacetamide ratio and glycerol/CA ratio had great influence on the cross-section structure of membranes. Additionally, the membrane with homogeneous sponge-like porous structure could be prepared stably within certain limits of ratios. Under the premise of keeping the content of other components fixed, the separation membrane with a full sponge pore structure can be obtained when the ratio of glycerol/CA is ≥2.5 or the acetone/solvent ratio is between 0.25 and 0.5. Evaporation time and temperature, humidity and other membrane preparation conditions mainly affected the surface morphology and the pore size. This kind of high-performance membrane with homogeneous sponge-like pore and controllable surface morphology could be potentially used for bioseparation processes.

Atomic Oxygen Resistant Polysiloxane Coatings for Low Earth Orbit Space Structures

2015 ◽  
Vol 830-831 ◽  
pp. 699-702 ◽  
Author(s):  
G.N. Arjun ◽  
T.L. Lincy ◽  
T.S. Sajitha ◽  
S. Bhuvaneshwari ◽  
Thomas Deepthi ◽  
...  
Keyword(s):  
Reaction Time ◽  
Surface Morphology ◽  
Mass Loss ◽  
Atomic Oxygen ◽  
Thermo Gravimetric Analysis ◽  
Orbit Space ◽  
Solid Content ◽  
Low Earth Orbit ◽  
Gravimetric Analysis ◽  
Coating Materials

Polysiloxane resin copolymer was synthesized through acid catalyzed hydrolysis of methyl triethoxysilane (MTEOS) and diethoxytetramethyldisiloxane (DEOTMDS). The effect of reaction time on the properties of the polymer was studied and this copolymer was characterized by GPC, 29Si NMR, IR, TGA, viscosity, refractive index, specific gravity and solid content. 29Si NMR and IR showed characteristic signals of Si-O-Si linkage which confirmed the formation of the polymer. GPC and solid content analysis showed an increasing trend in molecular weight with reaction time. Thermo gravimetric analysis showed that the polymer was thermally stable upto ≈ 260°C and all the polymers gave a ceramic residue in the range of 77-80% at 900°C. Siloxane prepared inhouse and methyl phenyl silsequioxane (control) were used as coating materials and atomic oxygen (AO) resistance was evaluated on Al-Kapton, carbon polyimide composite and glass polyimide composite. The mass loss and surface morphology of the coated samples were measured at different time intervals. It is observed that mass loss of polysiloxane coated samples was very less, compared to coated control samples. The morphology of all the samples were studied using FESEM. Erosion kinetics and surface morphology investigation indicate that the polysiloxane coating possesses excellent AO resistance, and displays better cracking resistance on AO exposure.

scholarly journals Do ZnO and Al2O3 Nanoparticles Improve the Anti-Bacterial Properties of Cellulose Acetate-Chitosan Membrane?

2018 ◽  
Vol 156 ◽  
pp. 08009 ◽  
Author(s):  
Titik Istirokhatun ◽  
Ulva Yuni ◽  
Pertiwi Andarani ◽  
Heru Susanto
Keyword(s):  
Antimicrobial Activity ◽  
Phase Separation ◽  
Surface Morphology ◽  
Cellulose Acetate ◽  
Water Permeability ◽  
Al2o3 Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Chitosan Membrane ◽  
Chitosan Membranes

Biofouling, due to the existence of bacteria in water, becomes one of the barriers in cellulose acetate (CA) membrane applications. Although chitosan has been incorporated into CA membranes, its antimicrobial activity has not been improved significantly yet. In this study, cellulose acetate-chitosan membranes were prepared by modification using ZnO and Al2O3 nanoparticles during phase separation method. The membranes were then characterized in term of water permeability, and surface morphology. The anti-bacteria property was examined by using gram-negative bacteria. Modification of cellulose acetate-chitosan membranes with ZnO and Al2O3 nanoparticles have not shown optimal results where no clear zones around the membrane are visible.

Enhancing the electrode performance of Co3O4 through Co3O4@a-TiO2 core–shell microcubes with controllable pore size

RSC Advances ◽  
2015 ◽  
Vol 5 (51) ◽  
pp. 40899-40906 ◽  
Author(s):  
Yanting Chu ◽  
Jinkui Feng ◽  
Yitai Qian ◽  
Shenglin Xiong
Keyword(s):  
Pore Size ◽  
High Capacity ◽  
Electrochemical Activity ◽  
Good Stability ◽  
Core Shell ◽  
Solvent Ratio ◽  
Electrode Performance

Co3O4@a-TiO2 structures have been realized by adjusting the solvent ratio. The excellent electrochemical activity of the composite is due to the good stability of TiO2 shell, high capacity of Co3O4 core, and the optimized porous size.

The Effect Of Weight Fraction And Size On The Properties Of Sago Particles Urea Formaldehyde Particleboard

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Tay Chen Chiang ◽  
Sinin Hamdan ◽  
Mohd Shahril Osman
Keyword(s):  
Urea Formaldehyde ◽  
Great Influence ◽  
Single Layer ◽  
Weight Fraction ◽  
Solid Content ◽  
Wood Products ◽  
Density Level ◽  
Testing Method ◽  
Uf Resin ◽  
Low Emission

We live in a world where wood products are hard to ignore. The sheer flexibility in the number of applications where the wood is used means that it is one of the most sought resources in the world. The wood products industry faces challenges in promoting sustainable management of forest resources. Composite materials have advantage of having an optimized performance, minimized weight and volume, cost effectiveness, chemical resistance and resistance to biodegradation. The research in this paper is focused on sago particles with adhesive of low emission urea formaldehyde (UF) resin 51.6% solid content. The fabrication and testing method are based on JIS A 5908 standard. A single-layer particleboard by using the sago particles has been established at targeted density level 600kg/m3. Particles with weight fractions of 90%, 85%, 80%, 75% and 70% were used in the fabrication of sago composite boards. The results of the test demonstrated that the samples with different weight fraction and size have great influence on the mechanical properties like: MOR, screw test and internal bonding. The findings had demonstrated that the level of weight fraction and size had affects the performance of a board. At the next stage of the research the comparison between sago and wood particleboard will be carried out to identify the feasibility of these materials in the industrial application.

Preparation of Fine Porous Ultrafiltration Membranes from Polyacrylonitrile

2020 ◽  
Vol 869 ◽  
pp. 437-442
Author(s):  
Alexey A. Yushkin ◽  
Alexey V. Balynin ◽  
Mikhail E. Efimov ◽  
Galina Karpacheva ◽  
Alexey V. Volkov
Keyword(s):  
Pore Size ◽  
Polymer Concentration ◽  
Volatile Component ◽  
Membrane Preparation ◽  
Solubility Parameters ◽  
Precipitation Method ◽  
Hansen Solubility Parameters ◽  
Casting Solution ◽  
Filtration Performance ◽  
Hansen Solubility

PAN membranes were prepared from mixture of good and weak solvents by two different methods. Immersion precipitation method with and without volatile component evaporation used for membrane preparation. From analysis of Hansen solubility parameters DMSO chosen as good solvent and acetone chosen as weak solvent. The effect of volatile weak solvent investigated on pore size and filtration performance. By evaporation of acetone, it was possible to increase polymer concentration on casting solution and obtain smaller pore size in comparison to membrane prepared from DMSO. Membranes prepared from DMSO/acetone without solvent evaporation had even lower pore size and higher filtration performances. It was shown, that presence of acetone creates more pronounced effect on pore size than increase of polymer concentration. As a result membranes with pore size 3.7 nm obtained from Acetone/DMSO mixture with composition 50:50 and polymer concentration 50 % by immersion precipitation Resulted membranes have permeance 23 kg/m2·h·bar and retention of Lysozime 99 %.

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