Sepiolite - Chitosan Biocompatible Foams v1

2021 ◽  
Author(s):  
celiamm not provided
Keyword(s):  
Freeze Drying ◽  
Good Option ◽  
Biodegradable Materials ◽  
High Porosity ◽  
Low Resistance ◽  
Macroporous Material

The foams are biohybrid, resistant, biocompatible, biodegradable materials that allow cyanobacteria to survive inside them and produce the desired biofuel. It is a macroporous material with high porosity. Its synthesis is relatively simple, and can be classified into three main steps: formation of the chitosan and sepiolite solutions, freeze-drying them and finally the introduction of the cells inside. This will result in a material with many possibilities, which, despite having some disadvantages such as its low resistance to liquids after synthesis, could be a good option by applying different modifications to suit the needs of the cells.

Controlling porosity and density of nanocellulose aerogels for superhydrophobic light materials

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 145-153 ◽  
Author(s):  
Chengua Yu ◽  
Feng Wang ◽  
Shiyu Fu ◽  
Lucian Lucia
Keyword(s):  
Contact Angle ◽  
Freeze Drying ◽  
Engine Oil ◽  
High Porosity ◽  
Water Mixture ◽  
Waste Engine Oil ◽  
Hydrophobically Modified ◽  
Static Contact ◽  
Oil Water ◽  
Hydrophobic Material

A very low-density oil-absorbing hydrophobic material was fabricated from cellulose nanofiber aerogels–coated silane substances. Nanocellulose aerogels (NCA) superabsorbents were prepared by freeze drying cellulose nanofibril dispersions at 0.2%, 0.5%, 0.8%, 1.0%, and 1.5% w/w. The NCA were hydrophobically modified with methyltrimethoxysilane. The surface morphology and wettability were characterized by scanning electron microscopy and static contact angle. The aerogels displayed an ultralow density (2.0–16.7 mg·cm-3), high porosity (99.9%–98.9%), and superhydrophobicity as evidenced by the contact angle of ~150° that enabled the aerogels to effectively absorb oil from an oil/water mixture. The absorption capacities of hydrophobic nanocellulose aerogels for waste engine oil and olive oil could be up to 140 g·g-1 and 179.1 g·g-1, respectively.

Use of Natural Biopolymers to Create Nanocomposite Materials

2020 ◽  
Vol 299 ◽  
pp. 299-304
Author(s):  
A.O. Makarova ◽  
L.R. Bogdanova ◽  
O.S. Zueva
Keyword(s):  
Carbon Nanotubes ◽  
Composite Materials ◽  
Sodium Alginate ◽  
Freeze Drying ◽  
Nanocomposite Materials ◽  
High Porosity ◽  
Composite Hydrogels ◽  
Xerogel Films

Method of carbon nanotubes disaggregation with the help of protein material, gelatin, has been proposed which facilitate to disperse evenly nanotubes in hydrogels based on gelatin and polysaccharides (sodium alginate or κ-carrageenan). In the obtained composite hydrogels carbon nanotubes are located in the biopolymer matrix, i.e. being in biocompatible form without losing their unique properties. The removal of water from the pores of the hydrogel by means of freeze drying allowed to obtain materials having high porosity and with included carbon nanotubes. The produced hydrogels can be used to create eco-friendly composite materials for biomedical and technical purposes. Depending on the tasks the developed systems can also be used in the forms of xerogel (films), cryogel, aerogel, and even in the form of powder, containing carbon nanotubes.

Freeze-drying preparation of porous diatomite ceramics with high porosity and low thermal conductivity

2020 ◽  
Vol 119 (4) ◽  
pp. 195-203
Author(s):  
Lei Han ◽  
Faliang Li ◽  
Haijun Zhang ◽  
Yuantao Pei ◽  
Longhao Dong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Freeze Drying ◽  
High Porosity ◽  
Low Thermal Conductivity

scholarly journals Anisotropic Cellulose Nanofibers/Polyvinyl Alcohol/Graphene Aerogels Fabricated by Directional Freeze-drying as Effective Oil Adsorbents

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 712 ◽  
Author(s):  
Lijie Zhou ◽  
Shengcheng Zhai ◽  
Yiming Chen ◽  
Zhaoyang Xu
Keyword(s):  
Polyvinyl Alcohol ◽  
Freeze Drying ◽  
High Efficiency ◽  
Cellulose Nanofibers ◽  
High Strength ◽  
Dip Coating ◽  
High Porosity ◽  
Water Contact ◽  
Water Separation ◽  
Composite Aerogel

Under the current situation of frequent oil spills, the development of green and recyclable high-efficiency oil-absorbing aerogel materials has attracted wide attention from researchers. In this study, we report a high-strength, three-dimensional hydrophobic cellulose nanofiber (CNF)/polyvinyl alcohol (PVA)/graphene oxide (GO) composite aerogel with an anisotropic porous structure, which was fabricated by directional freeze-drying technology using anisotropically grown ice crystals as a template, followed by hydrophobic treatment with a simple dip coating process. The prepared composite aerogel presented anisotropic multi-level pore microstructures, low density (17.95 mg/cm3) and high porosity (98.8%), good hydrophobicity (water contact angle of 142°) and great adsorption capacity (oil absorption reaching 96 times its own weight). More importantly, the oriented aerogel had high strength, whose compressive stress at 80% strain reached 0.22 MPa and could bear more than 22,123 times its own weight without deformation. Therefore, the CNF/PVA/GO composite aerogel prepared by a simple and easy-to-operate directional freeze-drying method is a promising absorbent for oil-water separation.

An Environment-Friendly Thermal Insulation Material from Porous Cellulose Aerogel

2013 ◽  
Vol 773 ◽  
pp. 487-491 ◽  
Author(s):  
Jian Jun Shi ◽  
Ling Bin Lu ◽  
Jing Ying Zhang
Keyword(s):  
Freeze Drying ◽  
Solvent System ◽  
Insulation Material ◽  
High Porosity ◽  
Porous Network ◽  
Environment Friendly ◽  
Cellulose Aerogel ◽  
Cellulose Hydrogel ◽  
Drying Technology ◽  
Insulation Performance

Cellulose hydrogel was prepared by using the NaOH/ Thiourea/ H2O as solvent system, cellulose aerogels were obtained by freeze-drying technology. The results showed that cellulose aerogel had porous network structure. Freeze-drying method was an effective way to prepare cellulose aerogel, and the volume shrinkage was 20.41%-28.36%. Bulk cellulose aerogel had low density, high porosity and fine mechanical strength. The density was low to 0.233g/cm3, and the porosity was up to 84.88%. The compressive strength was 5.7-8.2MPa. Cellulose aerogel had good heat insulation performance and thermal conductivity could be as low as 0.029 W/ (m·K). This work provided a foundation for the possibility of applying cellulose aerogels in the insulating material field.

scholarly journals Fabrication Of Carbon Aerogels From Coir For Oil Adsorption

2022 ◽  
Vol 964 (1) ◽  
pp. 012033
Author(s):  
Hieu M Nguyen ◽  
Khoi A Tran ◽  
Tram T N Nguyen ◽  
Nga N H Do ◽  
Kien A Le ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Oil Spills ◽  
Sol Gel ◽  
Urea Solution ◽  
Carbon Aerogels ◽  
Low Density ◽  
High Porosity ◽  
Motor Oil ◽  
Sol Gel Process ◽  
Oil Adsorption

Abstract Coir, known as coconut fibers, are an abundant cellulosic source in Vietnam, which are mostly discarded when copra and coconut water are taken, causing environmental pollution and waste of potential biomass. In this research, carbon aerogels from chemically pretreated coir were successfully synthesized via simple sol-gel process with NaOH-urea solution, economical freeze-drying, and carbonization. The samples, including pretreated coir, coir aerogels, and carbon aerogels, are characterized using FTIR spectroscopy, SEM, XRD spectroscopy, and TGA. The carbon aerogels exhibit low density (0.034–0.047 g/cm3), high porosity (97.63–98.32 %), and comparable motor oil sorption capacity (22.71 g/g). The properties of carbon aerogels are compared with those of coir aerogels, indicating such better values than those of coir aerogels. Coir-derived carbon aerogels is a potential replacement for the hydrophobically-coated cellulose aerogels in term of treating oil spills.

Manufactory and Properties of Poly(p-Phenylenebenzobisoxazole) Aerogels Prepared by a Simple Freeze-Drying Procedure

2020 ◽  
Vol 993 ◽  
pp. 662-668
Author(s):  
Yu Nong Wei ◽  
Guang Li ◽  
Sheng Lin Yang ◽  
Jun Hong Jin
Keyword(s):  
High Performance ◽  
Freeze Drying ◽  
Sol Gel ◽  
Fire Retardant ◽  
Decomposition Temperature ◽  
High Specific Surface Area ◽  
High Porosity ◽  
Cellulose Aerogel ◽  
Small Pore ◽  
Small Pore Diameter

Aerogels based on organic high performance fibers have been attracted great attention due to its excellent thermal and mechanical properties. Here, PBO nanofiber aerogel were prepared from the super-fiber PBO through a top-down process with a sol-gel process and a simple freeze-drying process, followed by thermal cross-linking. The prepared aerogel has a small volume shrinkage, a high specific surface area of 168.9 m2 /g and a small pore diameter of 1.356 nm. Because of its 3D porous structure, it results in a low density of 6 to 30 mg/cm3 and a high porosity (98%). The aerogel retains the molecular structure of PBO at the same time, which gives it initial thermal decomposition temperature up to 500 °C and a superior fire-retardant capability. PBO aerogel possesses good compressive properties with a yield stress of 0.44MPa at 80% strain and an elasticity modulus of 1.98 MPa which is higher than SiO2 and cellulose aerogel reported.

Preparation and Characterization of n-HA/Chitosan Scaffold Prepared by a New Method of Emulsion-Foaming/Freeze-Drying Process

2007 ◽  
Vol 544-545 ◽  
pp. 789-792 ◽  
Author(s):  
Li Zhang ◽  
Yu Bao Li ◽  
Pu Jiang Shi ◽  
Yi Zuo ◽  
Lan Wu
Keyword(s):  
Compressive Strength ◽  
Freeze Drying ◽  
Cell Attachment ◽  
Composite Scaffold ◽  
Testing Machine ◽  
Calculated Data ◽  
Tween 80 ◽  
New Method ◽  
High Porosity ◽  
Drying Process

A novel nano-hydroxyapatite/chitosan (n-HA/CS) composite scaffold with high porosity was developed by a new method of emulsion-foaming/freeze-drying process and was characterized by means of infrared spectroscopy (IR), scanning electronic microscopy (SEM) and universal material testing machine. In addition, the porosity and density of the scaffold were also calculated. IR result shows that the characteristic absorption peaks belonging to both CS and HA are present in their composite, and the slight band-shifts and peak-decrease suggest that some interactions have taken place between the two phases of CS and n-HA in the composite. SEM photo displays that, with the dosage increase of Tween-80, the prepared scaffold shows highly porous and interconnected structure, in which macropores and micropores coexist. The calculated data demonstrate that the porosity of the scaffold is proportional to the content of the emulsifier, while the compressive strength is inversely. When 15wt% emulsifier used, the porosity of the scaffold can be up to 90% and the density is 0.453g/cm3, while the corresponding compressive strength is about 2.4MPa. The newly developed n-HA/CS composite scaffolds may serve as a good 3-D substrate for cell attachment and migration in bone tissue engineering.

scholarly journals Development and Optimization of the Novel Fabrication Method of Highly Macroporous Chitosan/Agarose/Nanohydroxyapatite Bone Scaffold for Potential Regenerative Medicine Applications

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 434 ◽  
Author(s):  
Paulina Kazimierczak ◽  
Krzysztof Palka ◽  
Agata Przekora
Keyword(s):  
Regenerative Medicine ◽  
Compression Test ◽  
Freeze Drying ◽  
High Porosity ◽  
The Novel ◽  
Bone Scaffold ◽  
Simultaneous Application ◽  
Foaming Agent ◽  
Novel Scaffold ◽  
Gas Foaming

Bone scaffolds mimicking the three-dimensional bone structure are of essential importance for bone regeneration. The aim of this study was to develop and optimize the production method of highly macroporous bone scaffold composed of polysaccharide matrix (chitosan–agarose) reinforced with nanohydroxyapatite. The highly macroporous structure was obtained by the simultaneous application of a gas-foaming agent and freeze-drying technique. Fabricated variants of biomaterials (produced using different gas-foaming agent and solvent concentrations) were subjected to porosity evaluation and compression test in order to select the scaffold with the best properties. Then, bioactivity, cytotoxicity, and cell growth on the surface of the selected biomaterial were assessed. The obtained results showed that the simultaneous application of gas-foaming and freeze-drying methods allows for the production of biomaterials characterized by high total and open porosity. It was proved that the best porosity is obtained when solvent (CH3COOH) and foaming agent (NaHCO3) are applied at ratio 1:1. Nevertheless, the high porosity of novel biomaterial decreases its mechanical strength as determined by compression test. Importantly, novel scaffold is non-toxic to osteoblasts and favors cell attachment and growth on its surface. All mentioned properties make the novel biomaterial a promising candidate to be used in regenerative medicine in non-load bearing implantation sites.

scholarly journals RICE STRAW CELLULOSE AEROGELS

2018 ◽  
Vol 56 (2A) ◽  
pp. 118-125 ◽  
Author(s):  
Nguyen Truong Son
Keyword(s):  
Thermal Conductivity ◽  
Rice Straw ◽  
Freeze Drying ◽  
Soxhlet Extraction ◽  
High Porosity ◽  
Specific Density ◽  
Water Contact ◽  
X Ray ◽  
Oil Adsorption ◽  
Scanning Electron

In this study, cellulose was obtained from rice straw by dewaxing with Soxhlet extraction and treating with sodium hydroxide and hydrogen peroxide. The obtained cellulose was used to successfully fabricate cellulose aerogels with a binder by freeze drying technique. The materials were then functionalized with methyltrimethoxysilane (MTMS) to achieve hydrophobicity. The morphology, pore structure and other properties of the aerogels were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetrical analysis (TGA), thermal conductivity and water contact angle (WCA) measurements. The rice straw cellulose aerogels exhibited very low specific density (0.0412-0.0470 g/cm3), high porosity (> 96 %), superhydrophobicity (WCA > 137o) and low thermal conductivity (0.034-0.036 W/(m.K)). The aerogels showed good oil adsorption capacity of 15.66-16.09 g/g. 

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