The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Junkyo Suh - One of the best experts on this subject based on the ideXlab platform.
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gag augmented polysaccharide hydrogel a novel biocompatible and biodegradable material to support chondrogenesis
Journal of Biomedical Materials Research, 2000Co-Authors: Franklin V Sechriest, Yi Jian Miao, Christopher Niyibizi, Andrea Westerhausenlarson, Howard W T Matthew, Christopher H Evans, Junkyo SuhAbstract:The quality of articular cartilage engineered using a cell–polymer construct depends, in part, on the chemical composition of the biomaterial and whether that biomaterial can support the chondrocytic phenotype. Acknowledging the supportive influence of tissue-specific matrix molecules on the chondrocytic phenotype, we have combined chondroitin sulfate-A (CSA) and chitosan, a glycosaminoglycan (GAG) analog, to develop a novel biomaterial to support chondrogenesis. Chitosan is a polycatIonic repeating monosaccharide of β-1,4-linked glucosamine monomers with randomly located N-acetyl glucosamine units. Chitosan may be combined with the polyanIonic CSA such that Ionic Crosslinking results in hydrogel formation. Bovine primary articular chondrocytes, when seeded onto a thin layer of CSA–chitosan, form discrete, focal adhesions to the material and maintain many characteristics of the differentiated chondrocytic phenotype, including round morphology, limited mitosis, collagen type II, and proteoglycan production. Our findings suggest CSA–chitosan may be well suited as a carrier material for the transplant of autologous chondrocytes or as a scaffold for the tissue engineering of cartilage-like tissue. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 49, 534–541, 2000.
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gag augmented polysaccharide hydrogel a novel biocompatible and biodegradable material to support chondrogenesis
Journal of Biomedical Materials Research, 2000Co-Authors: Franklin V Sechriest, Yi Jian Miao, Christopher Niyibizi, Andrea Westerhausenlarson, Howard W T Matthew, Christopher H Evans, Junkyo SuhAbstract:The quality of articular cartilage engineered using a cell-polymer construct depends, in part, on the chemical composition of the biomaterial and whether that biomaterial can support the chondrocytic phenotype. Acknowledging the supportive influence of tissue-specific matrix molecules on the chondrocytic phenotype, we have combined chondroitin sulfate-A (CSA) and chitosan, a glycosaminoglycan (GAG) analog, to develop a novel biomaterial to support chondrogenesis. Chitosan is a polycatIonic repeating monosaccharide of beta-1,4-linked glucosamine monomers with randomly located N-acetyl glucosamine units. Chitosan may be combined with the polyanIonic CSA such that Ionic Crosslinking results in hydrogel formation. Bovine primary articular chondrocytes, when seeded onto a thin layer of CSA-chitosan, form discrete, focal adhesions to the material and maintain many characteristics of the differentiated chondrocytic phenotype, including round morphology, limited mitosis, collagen type II, and proteoglycan production. Our findings suggest CSA-chitosan may be well suited as a carrier material for the transplant of autologous chondrocytes or as a scaffold for the tissue engineering of cartilage-like tissue.
Zun Yuan - One of the best experts on this subject based on the ideXlab platform.
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facile construction of enhanced multiple interfacial interactions in epdm zinc dimethacrylate zdma rubber composites highly reinforcing effect and improvement mechanism of sealing resilience
Composites Part A-applied Science and Manufacturing, 2019Co-Authors: Zun YuanAbstract:Abstract Based on Zn2+-carboxyl coordination strategy, EPDM-g-Glu/ZDMA composite was prepared by grafting of maleic anhydride (MAH)/glutamic acid (Glu) onto EPDM chains via reactive melting process and in situ formation of zinc dimethacrylate (ZDMA) through convenient two-roll milling/hot-pressing process. Zn2+-carboxyl coordination was proved to be formed, and ZDMA uniformly dispersed in matrix and rapidly polymerized to form single rod-shaped PZDMA containing Zn2+-based Ionic multiplet during vulcanization, which was tightly embedded in matrix with strong interfacial interaction. Compared with EPDM/ZDMA composite, higher polymerization degree of ZDMA and thicker immobilized EPDM layer were achieved with reducing size of PZDMA clusters for EPDM-g-Glu/ZDMA composite. In addition, multiple interactions with higher covalent ( V e 1 ) and Ionic Crosslinking density formed. Moreover, higher retention of V e 1 after ageing was obtained, while thermo-oxidative ageing process was retarded with prolonged oxidation induction time. Thus simultaneously remarkable enhancement of energy dissipation, mechanical and durable sealing resilience performance were achieved for EPDM rubber.
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construction of multiple Crosslinking networks in epdm rubber synergistic reinforcing effect of graphene zinc dimethacrylate on epdm and improvement mechanism of sealing resilience
Composites Part A-applied Science and Manufacturing, 2019Co-Authors: Zun YuanAbstract:Abstract EPDM/Graphene (GN) - Zinc dimethacrylate (ZDMA) nano-composite was prepared by in situ formation of ZDMA in GN layers. Both EPDM and ZDMA molecules were confirmed to intercalate into GN layers with strong interfacial interactions and high efficiency. Compared with neat EPDM, addition of GN-ZDMA resulted in 291% increase of tensile strength and 48% increase of elongation at break, superior to that of EPDN/GN and EPDM/ZDMA. Furthermore, the increase in compression set and decrease in contact stress relaxation coefficient can be retarded during aging, resulting in enhancing durable sealing resilience. GN sheets were homogeneously embedded in matrix, which helped uniform distribution of ZDMA itself. During vulcanization process, multiple Crosslinking networks was constructed, including covalent Crosslinking from EPDM, ZDMA and aid of GN, and Ionic Crosslinking from poly-ZDMA, resulting in significant increase in Crosslinking density and retention ratio during aging, and thus exhibiting synergistic reinforcing and stabilizing effect of GN-ZDMA on EPDM.
Cai Wen - One of the best experts on this subject based on the ideXlab platform.
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an interpenetrating network biohydrogel of gelatin and gellan gum by using a combination of enzymatic and Ionic Crosslinking approaches
Polymer International, 2014Co-Authors: Cai WenAbstract:Gelatin is a popular substrate for cell culture applications due to its biocompatibility and biodegradability. However, the mechanical property of gelatin is not satisfactory in certain tissue engineering areas where tunable and higher mechanical strengths are required. To achieve this purpose without exposure of materials to cytotoxic chemicals or procedures, a new biohydrogel of gelatin and gellan gum with an interpenetrating network (IPN) structure was prepared using a combination of enzymatic and Ionic Crosslinking approaches. The gelation procedure and thermal stability of the IPN structure were demonstrated in detail by a rheological study. The resulting IPN biohydrogel exhibited significantly increased and tunable mechanical strength, decreased swelling ratios and lower degradation rate compared with pure gelatin gel. The composite biohydrogels supported the attachment and proliferation of L929 fibroblasts as shown in vitro. These results indicate that this mechanically robust biohydrogel has the promising potential for serving as a cell support in the field of tissue engineering. © 2013 Society of Chemical Industry
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mechanically robust gelatin alginate ipn hydrogels by a combination of enzymatic and Ionic Crosslinking approaches
Macromolecular Materials and Engineering, 2014Co-Authors: Cai WenAbstract:In this report, novel biopolymer hydrogels composed of gelatin and alginate with an interpenetrating polymer network (IPN) structure were prepared by a combination of enzymatic and Ionic Crosslinking approaches. The gelation processes of the IPN hydrogels were monitored using rheological techniques. The data confirmed the formation of dual networks: one gelatin network crosslinked by transglutaminase (TG) and another alginate network crosslinked by calcium ions. The results of mechanical testing revealed that the tensile and compressive strength of the hydrogels crosslinked in the presence of both TG and calcium ions were significantly improved. Preliminary studies have also shown that the hydrogels can support cell adhesion and spreading. These mechanically robust biopolymer hydrogels prepared by such biocompatible approaches are promising for the development of tissue engineering scaffolds.
Mohamed Hashem - One of the best experts on this subject based on the ideXlab platform.
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improving easy care properties of cotton fabric via dual effect of ester and Ionic Crosslinking
Carbohydrate Polymers, 2011Co-Authors: Mohamed Hashem, M H Elshakankery, S Abd M Elaziz, Moustafa M G Fouda, H M FahmyAbstract:Abstract To enhance the easy care finishing properties of cotton fabric along with maintaining its mechanical properties, a new route based on Ionic Crosslinking was employed. In this research work, pre-cationized cotton fabric was crosslinked using ammonium citrate in presence of sodium hypophosphite at 180 °C for 90 s. The effect of cationization level and ammonium citrate as well as silicon micro-emulsion softener concentrations on the performance properties of cotton fabric was determined. Results obtained show that the pre-cationization of cotton fabric having 0.09% nitrogen followed by Crosslinking with 6% ammonium citrate brings about an enhancement in both dry and wet recovery angles along with a slight improvement in TS. Furthermore, the pre-cationized sample having the nitrogen content of 0.09% was characterized before and after ester Crosslinking with 6% ammonium citrate (compared with an untreated sample) using thermo gravimetric analysis and Scanning Electron Microscope.
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enhancement of wrinkle free properties of carboxymethylated cotton fabric via Ionic Crosslinking with poly vinylpyrrolidone
Journal of Industrial Textiles, 2009Co-Authors: Mohamed Hashem, Brent Smith, Rakia Refaie, Kiral Goli, Peter J HauserAbstract:Incorporation of poly(vinylpyrrolidone) (PVP) in the structure of cotton, carboxymethylated cotton (CMC) or Ionically crosslinked cotton fabric induces besides ether Crosslinking of cotton cellulose, strong columbic forces and weaker forces such as dipole—dipole, hydrogen bonds, van der Waals, or hydrophobic interactions. The ether bonds are formed in the dry state (i.e., un-swelled state), whereas, the other interactions are formed in wet state (i.e., swelled state) of cotton fabrics. Both interactions greatly enhance wet and dry wrinkle recovery angle of cotton fabric without strength loss. Fixation of PVP onto cotton or CMC fabric was achieved thermally by curing the treated fabric at 140°C for 5 minutes. Higher wet and dry wrinkle recovery angles (WRA and DRA) were obtained with lower molecular weight PVP (3000 Da) compared with higher molecular weight one (8000 Da). The results obtained also show that a balance between WRA, DRA as high as 228° and 225°, respectively, could be obtained without loss in...
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Crosslinking of partially carboxymethylated cotton fabric via cationization
Journal of Cleaner Production, 2005Co-Authors: Mohamed Hashem, Rakia Refaie, A HebeishAbstract:Abstract A novel method for non-formaldehyde easy care finishing of cotton fabric based on Ionic Crosslinking has been examined. Accordingly, the cotton fabric was first partially carboxymethylated to impart to it the anIonic character through its reaction with monochloroacetic acid in alkaline medium. Application of reactive catIonic agent in alkaline medium affects Crosslinking of the resulting anIonic cotton in a second step. The reactive catIonic agent used was 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (Quat-188). Factors affecting the quaternization reaction of partially carboxymethylated cotton fabric (PCMC) have been studied. These factors include NaOH concentration, reaction time and temperature, quaternizing agent concentration as well as material to liquor ratio and method used for quaternization. The latter includes two methods, namely, the exhaustion method and the cold pad-batch method. Correlations between the degree of Crosslinking (expressed as nitrogen and carboxyl content) of quaternized PCMC fabric and the easy care properties were also made. Easy care properties include wet and dry crease recovery angles as well as tensile strength and elongation at break. Results obtained signify that: (a) optimum conditions for cationization of PCMC fabric are obtained when the Quat-188/sodium hydroxide molar ratio is 1/2 using the cold pad-batch method for 24 h; (b) the extent of cationization reaction, expressed as percent nitrogen, increases as the carboxyl content of the PCMC fabric increases, and (c) both wet and dry crease recovery angles of PCMC samples exhibit much higher values compared with that of untreated samples while both tensile strength and elongation at break display marginal improvements. These improvements depend mainly on the degree of Ionic Crosslinking.
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Ionic Crosslinking of cotton
Autex Research Journal, 2004Co-Authors: Peter J Hauser, Brent C Smith, Mohamed HashemAbstract:Cellulose Crosslinking is a very important textile chemical process, and is the basis for a vast array of durable press- and crease-resistant finished textile products. N-methylol crosslinkers containing formaldehyde give fabrics desirable properties of mechanical stability (e.g. crease resistance, anti-curl, shrinkage resistance, durable press), but also impart strength loss and the potential to release formaldehyde, a known human carcinogen. Other systems, e.g. polycarboxylic acids, have been tested with varying degrees of success. We have developed methods of forming Ionic crosslinks that provide outstanding crease-angle recovery performance, as well as complete strength retention in treated goods, without the potential for releasing any low-molecular weight reactive materials, such as formaldehyde. Our work is based on reactions of cellulose with materials that impart an Ionic character to the cellulose, e.g. chloroacetic acid for negative charges or 3-chloro-2-hydroxypropyl trimethyl ammonium chloride for positive charges. These reactions produce Ionic celluloses that can then sorb a polyIonic material of opposite charge to form crosslinks. Cellulose treated with cationized chitosan after carboxymethylation showed significant increases in crease recovery angles without strength loss.
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wrinkle recovery for cellulosic fabric by means of Ionic Crosslinking
Textile Research Journal, 2003Co-Authors: Mohamed Hashem, Peter J Hauser, Brent SmithAbstract:Methods are developed for imparting crease angle recovery performance to cellulosic fabrics based on durable Ionic crosslinks. These methods, which avoid the formaldehyde release of conventional finishes, include treating cellulose with chloroacetic acid (or an other reactive anion) and cationized chitosan (or another polycation). Alternative methods include treating cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride or another cationization reagent) and a polyanion, or with chloroacetic acid and 3-chloro- 2-hydroxypropyl trimethyl ammonium chloride. A method for producing highly catIonic chitosan is also presented. Crease angle recovery and strength data are correlated to the amount of polyelectrolyte add-on.
Zhan Lin - One of the best experts on this subject based on the ideXlab platform.
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a robust network binder with dual functions of cu2 ions as Ionic Crosslinking and chemical binding agents for highly stable li s batteries
Journal of Materials Chemistry, 2018Co-Authors: Yanxiong Fang, Feifei Dong, Minghao Sun, Zhan Lin, Payam Kaghazchi, Shanqing Zhang, Qian Bo-zhang, Jie LiuAbstract:Binders play a crucial role in improving the electrochemical performance of batteries. The major challenges associated with the sulfur cathode in lithium-sulfur (Li–S) batteries are up to 76% volume change during cycling from sulfur (S) to lithium sulfide (Li2S) and the shuttle effect of polysulfide anions, resulting in poor cycling performance. Herein, we design a network binder through the Crosslinking effect of sodium alginate (SA) and Cu2+ ions (named the SA–Cu binder), in which Cu2+ ions work not only as an Ionic Crosslinking agent for a robust network structure, but also as a chemical binding agent for polysulfide anions. The robust network binder buffers large volume variations during cycling, while electropositive Cu2+ ions immobilize polysulfide anions through strong chemical binding. The resulting sulfur electrode delivers a capacity of 925 mA h g−1 after 100 cycles at 0.2C, which is much higher than those of sulfur electrodes with only SA and PVDF binders. Due to the robust mechanical properties of the SA–Cu binder, a high-loading and crack-free sulfur electrode, i.e., a sulfur loading up to 8.05 mg cm−2, is also achieved and delivers a high areal capacity up to 9.5 mA h cm−2. This study paves a new way to immobilize polysulfide anions using the dual functions of Cu2+ ions as both the Ionic Crosslinking and chemical binding agents, which could open up a new direction for advanced binders for Li–S batteries in the near future.
