scholarly journals Preparation and Properties of Novel Superhydrophobic Cellulose Nanofiber Aerogels

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Guoqing Liu ◽  
Jing Li ◽  
Xiaodong Li ◽  
Xiangjun Pan ◽  
Chao Qian
Keyword(s):  
Thermal Insulation ◽  
Raw Materials ◽  
Sol Gel ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Laser Flash ◽  
Cellulose Nanofiber ◽  
Water Contact ◽  
Before And After

The superhydrophobic cellulose nanofiber aerogels were prepared via sol-gel and subsequent freeze-drying with cellulose nanofibers as raw materials and perfluorohexyl ethyl trimethoxysilane and 3-aminopropyl trimethoxysilane as modifying monomers. The effect of volume ratio and total dosage of the two modifying monomers on the superhydrophobic properties was investigated, and the property variations of the cellulose nanofibers before and after modification were also characterized by FT-IR, XRD, TGA, SEM, XPS, and laser flash diffusivity apparatus. The results showed that the modifying monomers were successfully grafted onto cellulose nanofibers, and the prepared modified cellulose nanofiber aerogels had higher thermal stability. After modification, a micron-level arrayed three-dimensional grid superhydrophobic surface structure was constructed, and the surface energy was reduced. The prepared aerogels exhibited superhydrophobicity with a water contact angle up to 151° and excellent thermal insulation performance with a thermal conductivity of 0.035 W·m−1·K−1, which displayed promising application potential in the field of thermal insulation and waterproof materials.

scholarly journals Construction of the Cellulose Nanofibers (CNFs) Aerogel Loading TiO2 NPs and Its Application in Disposal of Organic Pollutants

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1841
Author(s):  
Kang Li ◽  
Xuejie Zhang ◽  
Yan Qin ◽  
Ying Li
Keyword(s):  
High Efficiency ◽  
Sol Gel ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
Good Mechanical Property ◽  
Polar Groups ◽  
Dimensional Network ◽  
Natural Polysaccharide ◽  
Valuable Method ◽  
Adsorption Capability

Aerogels have been widely used in the adsorption of pollutants because of their large specific surface area. As an environmentally friendly natural polysaccharide, cellulose is a good candidate for the preparation of aerogels due to its wide sources and abundant polar groups. In this paper, an approach to construct cellulose nanofibers aerogels with both the good mechanical property and the high pollutants adsorption capability through chemical crosslinking was explored. On this basis, TiO2 nanoparticles were loaded on the aerogel through the sol-gel method followed by the hydrothermal method, thereby the enriched pollutants in the aerogel could be degraded synchronously. The chemical cross-linker not only helps build the three-dimensional network structure of aerogels, but also provides loading sites for TiO2. The degradation efficiency of pollutants by the TiO2@CNF Aerogel can reach more than 90% after 4 h, and the efficiency is still more than 70% after five cycles. The prepared TiO2@CNF Aerogels have high potential in the field of environmental management, because of the high efficiency of treating organic pollutes and the sustainability of the materials. The work also provides a choice for the functional utilization of cellulose, offering a valuable method to utilize the large amount of cellulose in nature.

scholarly journals Complex Aerogels Generated from Nano-Polysaccharides and Its Derivatives for Oil–Water Separation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1593 ◽  
Author(s):  
Hajo Yagoub ◽  
Liping Zhu ◽  
Mahmoud H. M. A. Shibraen ◽  
Ali A. Altam ◽  
Dafaalla M. D. Babiker ◽  
...  
Keyword(s):  
Guar Gum ◽  
Corn Oil ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

The complex aerogel generated from nano-polysaccharides, chitin nanocrystals (ChiNC) and TEMPO-oxidized cellulose nanofibers (TCNF), and its derivative cationic guar gum (CGG) is successfully prepared via a facile freeze-drying method with glutaraldehyde (GA) as cross-linkers. The complexation of ChiNC, TCNF, and CGG is shown to be helpful in creating a porous structure in the three-dimensional aerogel, which creates within the aerogel with large pore volume and excellent compressive properties. The ChiNC/TCNF/CGG aerogel is then modified with methyltrichlorosilane (MTCS) to obtain superhydrophobicity/superoleophilicity and used for oil–water separation. The successful modification is demonstrated through FTIR, XPS, and surface wettability studies. A water contact angle of 155° on the aerogel surface and 150° on the surface of the inside part of aerogel are obtained for the MTCS-modified ChiNC/TCNF/CGG aerogel, resulting in its effective absorption of corn oil and organic solvents (toluene, n-hexane, and trichloromethane) from both beneath and at the surface of water with excellent absorption capacity (i.e., 21.9 g/g for trichloromethane). More importantly, the modified aerogel can be used to continuously separate oil from water with the assistance of a vacuum setup and maintains a high absorption capacity after being used for 10 cycles. The as-prepared superhydrophobic/superoleophilic ChiNC/TCNF/CGG aerogel can be used as a promising absorbent material for the removal of oil from aqueous media.

Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540025 ◽  
Author(s):  
Hitoshi Takagi ◽  
Antonio N. Nakagaito ◽  
Kazuya Kusaka ◽  
Yuya Muneta
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Mechanical Treatment ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Tensile Tests ◽  
Cellulose Nanofiber ◽  
Paper Sludge ◽  
Reinforcing Effect ◽  
Mechanical And Physical Properties

Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

scholarly journals Natural Polymers for 3D Bioprinting of Organs

2020 ◽  
pp. 30-40
Author(s):  
Galina Sroslova ◽  
Yuliya Zimina ◽  
Elena Nesmeyanova ◽  
Margarita Postnova
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Three Dimensional ◽  
Biologically Active ◽  
Artificial Organs ◽  
Gel Point ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
Natural Polymers ◽  
Biological Origin

Three-dimensional (3D) bioprintingis a well-known promising technology for the production of artificial biological organs providing unprecedented versatility for manipulating cells and other biomaterials with precise control of their location in space. Over the past decade, a number of 3D bioprinting technologies have been developed. Unlike traditional manufacturing technologies, 3D bioprinting allows to produce individual or personalized fabric designs. This helps to deposit cells of the desired type with selected biomaterials and desired biologically active substances. Natural polymers play a leading role in maintaining cellular and biomolecular processes before, during, as well as after three-dimensional bioprinting. Polymers of biological origin can be extracted from natural raw materials by means of physical or chemical methods. These polymers are widely used as effective hydrogels for loading cells to form tissues, build a vascular, nervous, lymphatic network, and also to implement multiple biological, biochemical, physiological, biomedical and other functions. Any natural polymers that have a sol-gel phase transition (i.e., a gel point) under certain conditions can be printed using the automatic layer-by-layer deposition method. In fact, very few of them can be printed under various conditions (low temperature, without the help of physical, chemical, biochemical crosslinking of the incorporated polymer chains). Thus, not all natural polymers can meet all the basic requirements for 3D bioprinting. As a rule, natural polymers as the main component of various inks, which contain cells suspended in a specific medium, must meet several basic requirements for successful 3D bioprinting of organs, as well as clinical applications. These include biocompatibility, that is, non-toxic or without apparent toxicity; biodegradability (unlikenon-biodegradable polymers can be used as auxiliary structures); biostability with sufficiently high mechanical strength both at the time of processing and during operation; bioprinterness (workability). This review is devoted to modern research in the field of natural polymers used to print biological artificial organs.

THE STABILITY OF SUPERHYDROPHOBIC COTTON FABRICS PREPARED BY SOL–GEL COATING OF SiO2 AND TiO2

2013 ◽  
Vol 20 (06) ◽  
pp. 1350064 ◽  
Author(s):  
XUE-WEI WANG ◽  
CUI GUO ◽  
ZHI-HAO YUAN
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Volume Ratio ◽  
Sodium Silicate Solution ◽  
Cotton Fabrics ◽  
Contact Angles ◽  
Light Irradiation ◽  
Water Contact ◽  
Uv Light Irradiation ◽  
Silica And Titania

Superhydrophobic cotton fabrics are prepared using silica and titania hybrid sol and hexadecyltrimethoxysilane. The surface morphology of cotton fabrics is characterized by scanning electron microscopy. The water contact angles on the as-prepared superhydrophobic cotton fabrics is 159° when the volume ratio between sodium silicate solution and titania sol is 1:3, and the corresponding cotton fabrics can keep the contact angle of 152° after 10 cycles of home machine washing. Meanwhile the treated cotton fabrics can also keep superhydrophobicity after 60 min of UV light irradiation. These results indicate that the cotton fabrics treated with silica and titania hybrid sol and modified with hexadecyltrimethoxysilane show excellent superhydrophobic stability under washing and UV light irradiation. This paper provides the new notion and beneficial reference for the application of the superhydrophobic cotton fabrics in the future.

The study of knitted fabric thermal insulation using thermography and finite volume method

2016 ◽  
Vol 87 (6) ◽  
pp. 643-656 ◽  
Author(s):  
Adam K Puszkarz ◽  
Izabella Krucinska
Keyword(s):  
Thermal Insulation ◽  
Thermal Imaging ◽  
Raw Materials ◽  
Three Dimensional ◽  
Temperature Gradients ◽  
Ambient Conditions ◽  
Knitted Fabrics ◽  
Imaging Camera ◽  
Three Dimensional Models ◽  
Volume Method

The article concerns the widespread issue of thermal comfort; investigations into textiles and thermal insulation problems are presented. Materials that were tested include double-layer knitted fabrics with potential application in multi-layer garments addressed to a specific group of users. The investigated materials were constructed with the following raw materials: cotton, polypropylene, polyester, polyamide, bamboo, and viscose. The textiles with a comparable geometric structure and different composition were tested for their thermal insulation. In the experimental section the temperature gradients in specific constant ambient conditions using a thermal imaging camera were obtained. In the simulation section three-dimensional models of actual textiles were designed and the temperature gradients on the basis of performed simulations were calculated. Both measurements and simulations yielded comparable results and showed that the comparatively thick knitted fabrics’ thermal insulation strongly depends on the raw materials from which they were made and less on the parameters of the yarn.

Fabrication and Properties of 3D-Cf/Mullite Composites with SiC Interfacial Coatings

2013 ◽  
Vol 833 ◽  
pp. 150-153 ◽  
Author(s):  
Ke Wei Dai ◽  
Chen Chen Zhang ◽  
Qing Song Ma ◽  
Hai Tao Liu
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Great Improvement ◽  
Carbothermal Reduction ◽  
Raw Materials ◽  
Sol Gel ◽  
Three Dimensional ◽  
Retention Rates ◽  
Sol Gel Process ◽  
Sic Coatings

Three-dimensional carbon fiber reinforced mullite composites (3D-Cf/mullite) were fabricated by sol-gel method with diphasic mullite sol as raw materials. SiC interfacial coatings were deposited by polycarbosilane infiltration and pyrolysis before sol-gel process. The as-fabricated composites showed 285.7MPa in flexural strength, relatively close to 277.6MPa of those without coatings. After treated at 1300°C and 1500°C in Ar atmosphere for 1h, the retention rates of flexural strength were 80.0% and 69.9%, respectively, which showed a great improvement compared to the composites without coatings. This was attributed to the prevention of carbothermal reduction between carbon fiber and matrix by SiC coatings.

scholarly journals Preparation of Silica Aerogels by Ambient Pressure Drying without Causing Equipment Corrosion

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1935 ◽  
Author(s):  
Lixiao Zhu ◽  
Yali Wang ◽  
Suping Cui ◽  
Feihua Yang ◽  
Zuoren Nie ◽  
...  
Keyword(s):  
Pore Structure ◽  
Raw Materials ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Silica Aerogels ◽  
Ambient Pressure Drying ◽  
Molar Ratio ◽  
Insulation Property ◽  
Water Contact ◽  
Thermal Insulation Property

The silica aerogels were prepared via a sol-gel technique and ambient pressure drying by using industrial solid wastes, dislodged sludges, as raw materials. A strategy was put forward to reduce the corrosion of equipment during the drying procedure. The pore structure, hydrophobicity, and thermal insulation property of the obtained samples were investigated in detail. The results show that the corrosion can be effectively avoided by using an equimolar mixture of trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDS) as silylation agents. At a Si:TMCS:HMDS molar ratio of 1:0.375:0.375, the silica aerogels possess a desirable pore structure with a pore volume of 3.3 ± 0.1 cm3/g and a most probable pore size of 18.5 nm, a high hydrophobicity with a water contact angle of 144.2 ± 1.1°, and a low thermal conductivity of 0.031 ± 0.001 W/(m∙K).

Highly Transparent Superhydrophobic Surfaces from Silica Aerogel by Sol-Gel Method

2013 ◽  
Vol 756-759 ◽  
pp. 150-153 ◽  
Author(s):  
Tao Tao Zhang ◽  
Jing Huang ◽  
Rui Zhi Zhang ◽  
Peng Yan Mao ◽  
Pan Fang
Keyword(s):  
Silica Aerogel ◽  
Raw Materials ◽  
Sol Gel ◽  
Hydrophobic Effect ◽  
Three Dimensional ◽  
Dip Coating ◽  
Scanning Electron Micrographs ◽  
High Porosity ◽  
Gel Method ◽  
Sol Gel Method

We study the preparation of thin film on the glass substrate with the method of dip coating, which is based on methanol and MTMS as raw materials, making them form silica aerogel by sol-gel method. Scanning electron micrographs (SEM) show that such a film possesses a porous three-dimensional network structure. The high porosity and low refractive index determine that the transmittance rate can reach 90%. The prepared film also exhibited apparent hydrophobic effect, with the contact angle of 156.3°and rolling angle of less than 10°. The transparency and superhydrophobic of the film make it suitable as multifunctional coatings for many application fields including solar cells, cellphones and a variety of electron device.

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