Zr(IV)-Crosslinked Polyacrylamide/Polyanionic Cellulose Composite Hydrogels with High Strength and Unique Acid Resistance

2019 ◽  
Vol 57 (15) ◽  
pp. 981-991 ◽  
Author(s):  
Xiaofu Dai ◽  
Jianquan Wang ◽  
Fei Teng ◽  
Ziqiang Shao ◽  
Xiaonan Huang
Keyword(s):  
Acid Resistance ◽  
High Strength ◽  
Composite Hydrogels ◽  
Cellulose Composite

scholarly journals Preparation and Swelling Behaviors of High-Strength Hemicellulose-g-Polydopamine Composite Hydrogels

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 186
Author(s):  
Jiayan Ge ◽  
Kaiqi Gu ◽  
Kewen Sun ◽  
Xinyue Wang ◽  
Shuangquan Yao ◽  
...  
Keyword(s):  
Water Retention ◽  
High Strength ◽  
Release Behavior ◽  
Ph Responsive ◽  
Composite Hydrogels ◽  
Hydrogel Network ◽  
Microsphere Size ◽  
Chemical Cross Linking ◽  
Swelling Behaviors ◽  
Good Water Retention

Hemicellulose-based composite hydrogels were successfully prepared by adding polydopamine (PDA) microspheres as reinforcing agents. The effects of PDA microsphere size, dosage, and nitrogen content in hydrogel on the mechanical and rheological properties was studied. The compressive strength of hydrogel was increased from 0.11 to 0.30 MPa. The storage modulus G’ was increased from 7.9 to 22.0 KPa. The gaps in the hemicellulose network are filled with PDA microspheres. There is also chemical cross-linking between them. These gaps increased the density of the hydrogel network structure. It also has good water retention and pH sensitivity. The maximum cumulative release rate of methylene blue was 62.82%. The results showed that the release behavior of hydrogel was pH-responsive, which was beneficial to realizing targeted and controlling drug release.

scholarly journals High strength and low swelling composite hydrogels from gelatin and delignified wood

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shennan Wang ◽  
Kai Li ◽  
Qi Zhou
Keyword(s):  
Mechanical Strength ◽  
High Strength ◽  
Honeycomb Structure ◽  
Composite Hydrogel ◽  
High Porosity ◽  
High Mechanical Strength ◽  
Composite Hydrogels ◽  
Freeze Dried ◽  
Strength And Stiffness ◽  
Phosphate Buffered Saline

Abstract A delignified wood template with hydrophilic characteristics and high porosity was obtained by removal of lignin. Gelatin was infiltrated into the delignified wood and further crosslinked with a natural crosslinker genipin to form hydrogels. The composite hydrogels showed high mechanical strength under compression and low swelling in physiological condition. The effect of genipin concentrations (1, 50 and 100 mM) on structure and properties of the composite hydrogels were studied. A porous honeycomb structure with tunable pore size and porosity was observed in the freeze-dried composite hydrogels. High elastic modulus of 11.82 ± 1.51 MPa and high compressive yield stress of 689.3 ± 34.9 kPa were achieved for the composite hydrogel with a water content as high as 81%. The equilibrium water uptake of the freeze-dried hydrogel in phosphate buffered saline at 37 °C was as low as 407.5%. These enables the delignified wood structure an excellent template in composite hydrogel preparation by using infiltration and in-situ synthesis, particularly when high mechanical strength and stiffness are desired.

scholarly journals Crush and Acid Resistance of Microsphere Narrow Fractions from Fly Ash as the Basis of Composite Materials

2020 ◽  
pp. 189-200
Author(s):  
Galina V. Akimochkina ◽  
Elena S. Rogovenko ◽  
Elena V. Fomenko
Keyword(s):  
Weight Loss ◽  
Composite Materials ◽  
Fly Ash ◽  
Raw Materials ◽  
Compressive Loading ◽  
Acid Resistance ◽  
High Strength ◽  
Average Diameter ◽  
Narrow Fraction ◽  
Pulverized Combustion

The crush test and acid resistance of microsphere narrow fractions with average diameter dav of 5, 8 and 25 μm of the SiO2–Al2O3–FeO system and with dav of 4 and 10 μm the CaO–SiO2–Al2O3– FeO system separated from fly ash from pulverized combustion of Ekibastuz and Irsha-Borodinsky coals were studied. It has been established that all investigated ash fractions of both raw materials are characterized by high strength: microspheres of a larger narrow fraction with dav = 25 μ m a re not destroyed by compressive loading at pressures up to 51.7 MPa, dispersed narrow fractions of microspheres with dav ≤ 10 μm – up to 68.9 MPa. Microsphere narrow fractions with aluminosilicate composition have satisfactory acid resistance; the weight loss after treatment with 15 % hydrochloric acid at 65 °C for 30 minutes was 10–15 wt. %

Geopolymer Sourced with Fly Ash and Industrial Aluminum Waste for Sustainable Materials

2020 ◽  
pp. 676-696
Author(s):  
Sujitra Onutai ◽  
Sirithan Jiemsirilers ◽  
Takaomi Kobayashi
Keyword(s):  
Fly Ash ◽  
Industrial Waste ◽  
Raw Materials ◽  
Acid Resistance ◽  
High Strength ◽  
Microwave Oven ◽  
Silicate Material ◽  
High Acid ◽  
Alumino Silicate ◽  
Geopolymer Cement

Geopolymer is alumino-silicate material which can apply for many applications due to that geopolymers have several attractive properties of high strength, low permeability, high acid resistance, hazardous materials, and immobilization of toxic materials. This chapter presents synthesis of the dense and the porous structures of geopolymer by using fly ash and industrial waste as the raw materials. Aluminum hydroxide waste (Al-waste) and fly ash (FA) were used to synthesis the dense geopolymers for cement materials. The Al-waste based geopolymer influenced the geopolymer strength, when sodium hydroxide (NaOH) concentration was changed at different curing temperatures. As preliminary microwave oven was exposed in the lower NaOH paste of geopolymer, the successful synthesis of geopolymer cement was obtained. In addition, porous fly ash geopolymers was achieved using a household microwave oven. The geopolymer paste was cured within 1 min by using a microwave oven at different output power. Porous geopolymers were formed immediately as ued at 850 W power of the microwave oven.

Multi-scale characterisation of deuterated cellulose composite hydrogels reveals evidence for different interaction mechanisms with arabinoxylan, mixed-linkage glucan and xyloglucan

Polymer ◽  
2017 ◽  
Vol 124 ◽  
pp. 1-11 ◽  
Author(s):  
Marta Martínez-Sanz ◽  
Deirdre Mikkelsen ◽  
Bernadine M. Flanagan ◽  
Michael J. Gidley ◽  
Elliot P. Gilbert
Keyword(s):  
Interaction Mechanisms ◽  
Composite Hydrogels ◽  
Multi Scale ◽  
Cellulose Composite

Osmotic squat actuation in stiffness adjustable bacterial cellulose composite hydrogels

2020 ◽  
Vol 8 (12) ◽  
pp. 2400-2409
Author(s):  
Chen Qian ◽  
Taka-Aki Asoh ◽  
Hiroshi Uyama
Keyword(s):  
Osmotic Pressure ◽  
Bacterial Cellulose ◽  
Stimuli Responsive ◽  
Composite Hydrogels ◽  
Pressure Changes ◽  
Cellulose Composite

Stimuli-responsive stiffness change and squat actuation were realized in bacterial cellulose hydrogels by utilizing internal osmotic pressure changes.

scholarly journals Hydrophobic modification of nanocellulose and all-cellulose composite films using deep eutectic solvent as a reaction medium

Cellulose ◽  
2021 ◽  
Author(s):  
Matias Lakovaara ◽  
Juho Antti Sirviö ◽  
Mostafa Y. Ismail ◽  
Henrikki Liimatainen ◽  
Rafal Sliz
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Composite Films ◽  
Deep Eutectic Solvent ◽  
Reaction Medium ◽  
High Strength ◽  
Contact Angles ◽  
Angle Measurements ◽  
Diffuse Reflectance Infrared ◽  
Cellulose Composite

Abstract In this work, deep eutectic solvent (DES) based on imidazole and triethylmethylammonium chloride was used as a reaction medium for the esterification of cellulose nanofiber (CNF) and all-cellulose composite (ACC) films with n-octylsuccinic anhydride (OSA) to obtain high strength and sustainable films with increased hydrophobicity. Diffuse reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy were used to prove the success of the modification. The mechanical strength of the modified films was analyzed in dry, humid, and wet conditions, and the hydrophobicity of the films was indicated in terms of contact angle measurements. In addition, water absorption and transparency of the films were characterized. The modification was proven to be simple and fast, and mild conditions of 80 °C reaction temperature and 1 h reaction time were used. DES/OSA- modified CNF film exhibited better mechanical properties in dry, humid, and wet conditions compared to reference CNF film, and DES/OSA-modified ACC film displayed notable higher mechanical properties in wet state compared to that of reference CNF film (31 MPa tensile strength and 6.1% strain at break vs. 18 MPa and 2.2%, respectively). These improvements were partly attributed to higher contact angles of modified films (ACC-DES/OSA 60° and CNF-DES/OSA 51°) compared to CNF film (37°). Graphic abstract

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