scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

Application of an N-Methylol Crosslinking Agent to Cotton from an Emulsion System

1977 ◽  
Vol 47 (5) ◽  
pp. 328-332 ◽  
Author(s):  
S. M. Betrabet ◽  
E. H. Daruwalla ◽  
S. M. Doshi
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Water Content ◽  
Crosslinking Agent ◽  
Cross Linking ◽  
Emulsion System ◽  
Water Emulsion ◽  
Preferential Uptake ◽  
Different Levels

Application of DMDHEU from a kerosene-water emulsion system at different levels of water content in the system has been examined with respect to the extent of crosslinking and mechanical properties of the finished fabrics. As the water content of the treating bath is decreased, both wet and dry wrinkle-recovery angles, bound nitrogen, and bound HCHO in the crosslinked fabric increase, but there is no improvement noticed in the wrinkle-recovery/mechanical properties relationship. The increase in the extent of cross linking during application from the emulsion system appears to be due to preferential uptake of the aqueous solution containing the crosslinking agent from the emulsion system.

Interaction of Surfactants and Reaction Media on Photolysis of Chlorimuron and Metsulfuron

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 620-624 ◽  
Author(s):  
S. Kent Harrison ◽  
Sandra M. Thomas
Keyword(s):  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Water Glass ◽  
Laboratory Experiments ◽  
Nonionic Surfactants ◽  
Aqueous Media ◽  
Glass Slides ◽  
Leaf Residue ◽  
Corn Residue ◽  
Reaction Media

Laboratory experiments were conducted to determine the effects of nonionic surfactants and reaction media (water, glass, and corn leaf residue) on photolysis and subsequent phytotoxicity of chlorimuron and metsulfuron residues. Oxysorbic and octoxynol enhanced rates of chlorimuron and metsulfuron photolysis in aqueous solution and on glass slides compared to controls with no surfactant. Enhanced photolysis of chlorimuron by surfactants was greatest on glass, where 93 and 89% loss occurred after 48 h exposure to ultraviolet light in the presence of oxysorbic and octoxynol, respectively, compared to 38% loss with no surfactant. Similarly, surfactant-enhanced metsulfuron photolysis was greatest on glass with 37 and 67% loss after 48 h exposure in the presence of oxysorbic and octoxynol, respectively, compared to 9% loss with no surfactant. Photolysis of herbicides deposited on corn leaf residue was significantly slower than that on glass or in aqueous media at all exposure times and metsulfuron photolysis on corn residue was enhanced by surfactants only after 144 h exposure. Bioassays confirmed that phytotoxicity of photolyzed herbicide residues was negatively correlated (r=-0.94 for chlorimuron and r=-0.92 for metsulfuron) with loss of parent herbicide as measured by liquid chromatography.

Study of Puffing Cell Walls

2010 ◽  
Vol 113-116 ◽  
pp. 239-242
Author(s):  
Jian Qiu ◽  
Jean Ran Gao ◽  
Mon Lin Kuo ◽  
Jian Li
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Cell Wall ◽  
Nitric Acid ◽  
Cell Walls ◽  
Subsequent Treatment ◽  
Insulating Material ◽  
Trema Orientalis ◽  
Acid Aqueous Solution ◽  
Good Heat

Since wood is porous it also is a good heat and sound insulating material. Puffing the cell wall may lose certain level of mechanical properties but would increase its insulation properties. In this study, Trema orientalis wood was first treated with nitric acid aqueous solution to damage the S3 layer of cell walls, followed by puffing the cell wall inward with saturated urea and ZnCl2 solutions. Results indicated that treating Trema orientalis with 10% nitric acid at 100 oC for 20 minute damaged the S3 layer of cell walls, and the subsequent treatment with urea and ZnCl2 saturated solutions caused the fiber tracheid walls to swell up to 76%. Then, the swollen material was dried with critical CO2 fluid to obtain puffed wood. SEM examinations of nitric acid-treated samples showed that lignin were removed from the S3 layer surfaces and S3 mirofibrils were ruptured causing the entire secondary walls to swell inward.

scholarly journals STRENGTH ENHANCEMENT FROM HETEROGENEOUS NETWORKS OF ETHYLENE–PROPYLENE/ETHYLENE–PROPYLENE–DIENE

2011 ◽  
Vol 84 (4) ◽  
pp. 520-526 ◽  
Author(s):  
G. S. Buckley ◽  
D. Fragiadakis ◽  
C. M. Roland
Keyword(s):  
Mechanical Properties ◽  
Phase Separation ◽  
Chemical Modification ◽  
Random Copolymers ◽  
Cross Linking ◽  
Cross Link ◽  
Trade Off ◽  
Ethylene Propylene ◽  
Strength Enhancement ◽  
Miscible Blend

Abstract Random copolymers of ethylene and propylene are usually miscible with the corresponding unsaturated terpolymer (EPDM). Vulcanization of these blends yields networks in which only the EPDM is cross-linked. Despite chemical modification of the EPDM by its reaction with sulfur, there is no phase-separation evident during curing. The blend exhibits substantially higher strength than the corresponding pure EPDM networks, when compared at equal modulus. Thus, nearly miscible blend networks having a large disparity in component cross-linking can circumvent the usual trade-off between the stiffness and strength of elastomers. This exemplifies a general route to better mechanical properties via blends having a homogeneous phase morphology and whose components have substantially different cross-link densities.

scholarly journals Управление свойствами алмазоподобных кремнийуглеродных пленок

2020 ◽  
Vol 62 (10) ◽  
pp. 1612
Author(s):  
А.И. Попов ◽  
А.Д. Баринов ◽  
В.М. Емец ◽  
Т.С. Чуканова ◽  
М.Л. Шупегин
Keyword(s):  
Mechanical Properties ◽  
Transition Metals ◽  
Chemical Modification ◽  
Physical Properties ◽  
Structural Modification ◽  
Vacuum Chamber ◽  
High Efficiency ◽  
Carbon Films ◽  
Molecular Structures ◽  
Silicon Carbon

The possibilities of controlling the electrophysical and mechanical properties of amorphous diamond-like silicon-carbon films by the methods of structural, chemical and structural-chemical modification are considered. The factors of the structural modification were the bias voltage and its frequency during the synthesis of films, the argon pressure in the vacuum chamber, and precursors with different molecular structures. For chemical and structural-chemical modification, transition metals were introduced into the film with a concentration of up to 30 - 35 at. % The high efficiency of controlling the physical properties of the films by the considered methods is shown.

Selective Co(ii) removal from aqueous media by immobilizing silver nanoparticles within a polymer-matrix through a formaldehyde cross linking agent

RSC Advances ◽  
2015 ◽  
Vol 5 (30) ◽  
pp. 23340-23349 ◽  
Author(s):  
S. Siva ◽  
S. Sudharsan ◽  
R. Sayee Kannan
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Cation Exchange ◽  
Polymer Matrix ◽  
Cation Exchanger ◽  
Exchange Resin ◽  
Phenol Formaldehyde ◽  
Aqueous Media ◽  
Cation Exchange Resin ◽  
Cross Linking

A novel hybrid cation exchange resin was developed by encapsulating AgNPs within a macroporous phenol–formaldehyde cation exchanger for the removal of cobalt from aqueous solution.

Highly efficient and selective photocatalytic CO2 to CO conversion in aqueous solution

2020 ◽  
Vol 56 (27) ◽  
pp. 3851-3854 ◽  
Author(s):  
Xiaomin Chai ◽  
Hai-Hua Huang ◽  
Huiping Liu ◽  
Zhuofeng Ke ◽  
Wen-Wen Yong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Performance ◽  
Aqueous Media ◽  
Highly Efficient ◽  
Co Conversion

A Co-based complex displayed the highest photocatalytic performance for CO2 to CO conversion in aqueous media.

Polylactide-based stent coatings: biodegradable polymeric coatings capable of maintaining sustained release of the thrombolytic enzyme streptokinase

2020 ◽  
Vol 92 (8) ◽  
pp. 1329-1340
Author(s):  
A. G. Kolmakov ◽  
A. S. Baikin ◽  
S. V. Gudkov ◽  
K. N. Belosludtsev ◽  
E. O. Nasakina ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Films ◽  
De Novo ◽  
Membrane Surface ◽  
Aqueous Media ◽  
Polymeric Coatings ◽  
Short Term ◽  
Thrombolytic Activity ◽  
Viable Cells ◽  
Nitinol Stents

AbstractThe paper describes synthesis and testing of novel biodegradable polylactide-based polymer membranes with desired mechanical properties, which are capable of sustained and directed release of biomacromolecules with high molecular weight (in particular, streptokinase; m.w. 47 kDa). Streptokinase is a pharmaceutical agent, possessing a pronounced thrombolytic activity. The membranes synthesized had a percentage elongation of 2–11% and tensile strength of 25–85 MPa. They were biodegradable – yet being stored in aqueous media in the absence of biological objects, would be dissolved by no more than 10% in 6 months. The synthesized membranes were capable of controlled release of streptokinase into the intercellular space, with the enzyme retaining more than 90% of its initial activity. The rate of streptokinase release from the membranes varied from 0.01 to 0.04 mg/day per cm2 of membrane surface. The membrane samples tested in the work did not have any short-term toxic effects on the cells growing de novo on the membrane surface. The mitotic index of those cells was approximately 1.5%, and the number of non-viable cells on the surface of the polymer films did not exceed 3–4% of their total amount. The implantation of the synthesized polymers – as both individual films and coatings of nitinol stents – was not accompanied by any postoperative complications. The subsequent histological examination revealed no abnormalities. Two months after the implantation of polymer films, only traces of polylactide were found in the implant-surrounding tissues. The implantation of stents coated with streptokinase-containing polymers resulted in the formation of a mature and thick connective-tissue capsules. Thus, the polylactide membranes synthesized and tested in this work are biodegradable, possess the necessary mechanical properties and are capable of sustained and directed release of streptokinase macromolecules.

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