scholarly journals Getting Graft Cellulose Copolymers and Acrylic Monomers

2019 ◽  
Vol 8 (4) ◽  
pp. 719-723 ◽  
Keyword(s):  
Molecular Weight ◽  
Graft Copolymerization ◽  
Spectroscopic Studies ◽  
Degree Of Polymerization ◽  
Potassium Persulfate ◽  
Water Soluble ◽  
Active Centers ◽  
Solvent Absorption ◽  
Adsorption Interaction ◽  
Acrylic Monomers

Graft copolymers of acrylic monomers with cotton cellulose were obtained. The dependence of the degree and efficiency of grafting of acrylic acid and methyl methacrylate to cellulose on the concentration of monomer and initiator was investigated. Pre-adsorption of the initiator in the macromolecules of cellulose leads to an increase in the efficiency of the grafting. The efficiency of grafting is higher in those systems in which the initiator used is insoluble in the monomer solvent. Absorption of cellulose with an aqueous solution of the initiator - potassium persulfate, followed by removal of water was done. The advantage of using a water-soluble initiator is that during subsequent processing with a solution of monomer in an organic solvent, the desorption of the active centers does not occur. An increase in the concentration of theinitiator leads to an increase in the degree of grafting, a slight increase in the efficiency of the grafting, a significant decrease in the degree of polymerization and the molecular weight of the graft chains. In a heterogeneous process, an increase in the efficiency of grafting with an increase in the concentration of theinitiator is promoted by the additional adsorption interaction of the initiator molecules with the surface of cellulose. With an increase in the concentration of monomers, the overall degree of conversion slightly increases, the efficiency of grafting slightly decreases, the degree of grafting and the molecular weight of the graft chains increase significantly. The mechanism of graft copolymerization was investigated by comparative analysis of the IR and PMR spectra of cellulose, potassium persulfate, acrylic monomers and products of their interaction. Due to the results of spectroscopic studies, a scheme of graft copolymerization reactions has been proposed. The active centers of graft copolymerization are formed as a result of the reductive interaction of potassium persulfate, water and cellulose macromolecules.

Studies on the dehydrogenative polymerizations (DHPs) of monolignol β-glycosides: Part 4. Horseradish peroxidase-catalyzed copolymerization of isoconiferin and isosyringin

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Heterogeneous Reaction ◽  
Reaction System ◽  
Spectroscopic Studies ◽  
Degree Of Polymerization ◽  
Coniferyl Alcohol ◽  
Water Soluble ◽  
Sinapyl Alcohol ◽  
Homogeneous Phase ◽  
Heterogeneous Phase

Abstract Horseradish peroxidase (HRP)-catalyzed dehydrogenative copolymerization of guaiacyl (G)-type monolignol glycoside (isoconiferin, coniferyl alcohol γ-O-β-d-glucopyranoside, iso-G) and syringyl (S)-type monolignol glycoside (isosyringin, sinapyl alcohol γ-O-β-d-glucopyranoside, iso-S) were performed in continuous dehydrogenation mode (end-wise polymerization) to result in the formation of water-soluble lignin-like copolymers (iso-G/S-DHPs) in a homogeneous phase. The yield of iso-G/S-DHP increased with increasing iso-G content in the mixture of monomers from 23% (iso-G/iso-S 0:100) to 81% (iso-G/iso-S 50:50). The degree of polymerization (DP) of the resulting iso-G/S-DHP also increased proportionally from 7 (iso-G/iso-S 0:100) to 27 (iso-G/iso-S 50:50) as the iso-G content increased. It is obvious that iso-G plays an important role in the polymerization of iso-S. A similar tendency was also observed in conventional copolymerization of coniferyl alcohol (G-alc) and sinapyl alcohol (S-alc). The highest DP for DHP obtained in the conventional system was only ∼10 due to the heterogeneous reaction system. As the HRP-catalyzed monomer consumption rate of iso-S was greatly enhanced by addition of iso-G as a co-monomer, radical transfer from iso-G to iso-S seems to be plausible. Conventional copolymerization of G-alc and S-alc also supports this view. Spectroscopic studies and alkaline nitrobenzene oxidation analyses indicated that iso-G/S-DHPs had typical lignin structures composed of both G and S units. It was confirmed that the copolymerization behavior of the glycosides iso-G and iso-S in a homogeneous phase are well reflected by that of the monolignols G-alc and S-alc in a heterogeneous phase. Results also indicated that the presence of G-type co-monomers sensitively affects the polymerization of S-type monomers.

Antimicrobial Activity of a Low-Molecular-Weight Chitosan Obtained from Cellulase Digestion of Chitosan

2004 ◽  
Vol 67 (2) ◽  
pp. 396-398 ◽  
Author(s):  
GUO-JANE TSAI ◽  
SHU-LIN ZHANG ◽  
PEI-LING SHIEH
Keyword(s):  
Molecular Weight ◽  
Antimicrobial Activity ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Strong Activity ◽  
E Coli ◽  
Cellulase Digestion ◽  
Low Molecular Weight Chitosan ◽  
To Come

A water-soluble chitosan hydrolysate with high activity against Escherichia coli was obtained during cellulase digestion of chitosan for 18 h. This 18-h hydrolysate is composed of low-molecular-weight chitosan (LMWC), with a molecular weight of 12.0 kDa, and chitooligosaccharides, which are composed of sugars with a degree of polymerization of 1 to 8. LMWC has a strong activity at 100 ppm against many pathogens and yeast species, including Bacillus cereus, E. coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica serovar Typhi, and Saccharomyces cerevisiae, while the chitooligosaccharides have much weaker antimicrobial activity than does LMWC. Accordingly, the antimicrobial activity against E. coli in the 18-h hydrolysate proved to come mainly from the presence of LMWC.

scholarly journals ISOLATION, PHYSICO-CHEMICAL CHARACTERISTICS OF POLYSACCHARIDE ISOLATED FROM THE FRUIT BODY OF INONOTUS HISPIDUS

2021 ◽  
pp. 99-106
Author(s):  
Gulnoza Abduvahobovna Khalilova ◽  
Abbaskhan Sabirkhanovich Turaev ◽  
Bakhtiyor Ikromovich Muhitdinov ◽  
Al'bina Vasil'yevna Filatova ◽  
Saida Bokizhonovna Haytmetova ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Raw Materials ◽  
Structural Characteristics ◽  
Fruit Body ◽  
Chemical Properties ◽  
Spectroscopic Studies ◽  
Exchange Chromatography ◽  
Water Soluble ◽  
Raw Material ◽  
Size Exclusion

The article is devoted to the study of polysaccharides isolated from the basidiomycete raw material I. hispidus and studying their physical and chemical properties. Water-soluble polysaccharides were isolated from mushroom raw materials by the method of sequential water extraction and the yield was 9.44%. Polysaccharides were separated into neutral fractions by ion exchange chromatography and purified from proteins and peptides. During the separation process, it was determined that the polysaccharide sample consisted of homogeneous polysaccharides, while the carbohydrate content of the purified polysaccharide sample was 99.4%. The carbohydrate composition of polysaccharides was determined, it was found that the polysaccharide consists mainly of glucose residues and contains minor amounts of fructose and rhamnose residues. Molecular weight and molecular weight distribution were determined by size exclusion chromatography. The Mw of the polysaccharide sample obtained was 18.7 kDa, the polydispersity index was 1.3. The results of IR-, 1H- and 13C NMR spectroscopic studies have shown that the polysaccharide, according to its structural characteristics, belongs to the β-glucan type polysaccharide having β-(1,3) and β-(1,6)-glycosidic bounds.

scholarly journals New Method for Determining Total Dietary Fiber by Liquid Chromatography

2000 ◽  
Vol 83 (4) ◽  
pp. 1013-1019 ◽  
Author(s):  
Kazuhiro Ohkuma ◽  
Isao Matsuda ◽  
Yasuo Katta ◽  
Keisuke Tsuji
Keyword(s):  
Molecular Weight ◽  
Liquid Chromatography ◽  
Dietary Fiber ◽  
Internal Standard ◽  
Direct Determination ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Total Dietary Fiber ◽  
Insoluble Dietary Fiber

Abstract The molecular weight limit of water-soluble dietary fiber (SDF) determined by the Prosky method was studied by liquid chromatography (LC). It was confirmed that only SDF with an average degree of polymerization of 12 or higher can be determined by the Prosky method. Total dietary fiber (TDF) was determined by 2 additional methods using LC. In the first method, the total quantity of insoluble dietary fiber (IDF) and high molecular weight SDF (HMSDF) was determined according to the modified Prosky method (MES-TRIS buffer-based). The quantitatively collected final filtrate was analyzed by LC for the quantity of low molecular weight SDF (LMSDF), and the 2 quantities were totaled to obtain TDF. TDF values thus determined for rice, polished or unpolished, soybean flour, and pressed barley were higher than those determined by the Prosky method by approximately 6, 3.5, and 3.5%, respectively. In the second method, direct determination by LC analysis was done on samples after enzymatic treatment according to the Prosky method. Results showed that the determination of LMSDF, in particular, was highly accurate and more effective. In both of these methods, the quantity of LMSDF was determined from its chromatographic peak area ratio to glucose as an internal standard, which was produced by hydrolysis.

Production of hemicellulose oligomers from softwood chips using autohydrolysis followed by an enzymatic post-hydrolysis

Holzforschung ◽  
2017 ◽  
Vol 71 (7-8) ◽  
pp. 575-581 ◽  
Author(s):  
Vivien Deloule ◽  
Christine Chirat ◽  
Claire Boisset ◽  
Bertrand Toussaint ◽  
Jadwiga Chroboczek
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Enzymatic Hydrolysis ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Value Added ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Time Parameters ◽  
Temperature Time

AbstractIn the context of value added valorization of hemicelluloses (HCs), their soft extraction by autohydrolysis (AH) of softwood (SW) chips has been optimized via the temperature/time parameters (170°C/2 h, 170°C/1 h and 150°C/1 h). Two enzyme mixtures containing mainly a glucanase and a mannanase were used to decrease the degree of polymerization (DP) of the extracted HCs. Hydrolysates containing HCs were analyzed in terms of monomers and oligomers, molecular weight distribution (MWD) and chemical composition. The MW was strongly dependent on AH conditions: most of the water-soluble HCs with 1800 Da MW were obtained at 150°C/1 h. The parameters 170°C/2 h gave rise to MWs<1800 Da. Enzymatic hydrolysis (EH) reduced efficiently the DP of HCs, and the glucosidase was more efficient than the mannanase, but the former also hydrolyzed more oligomers into their monomeric components.

ANALISA KANDUNGAN BETA-GLUKAN LARUT AIR DAN LARUT ALKALI DARI TUBUH BUAH JAMUR TIRAM (Pleurotus ostreatus) DAN SHIITAKE (Lentinus edodes)

2013 ◽  
Vol 13 (3) ◽  
Author(s):  
Netty Widyastuti ◽  
Teguh Baruji ◽  
Henky Isnawan ◽  
Priyo Wahyudi ◽  
Donowati Donowati
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Immune System ◽  
Pleurotus Ostreatus ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Lentinus Edodes ◽  
Beta Glucan ◽  
Oyster Mushrooms ◽  
The Difference

Beta glucan is a polysaccharide compound, generally not soluble inwater and resistant to acid. Beta glucan is used as an immunomodulator (enhancing the immune system) in mammals is usually a beta-glucan soluble in water, easily absorbed and has a low molecular weight. Several example of beta-glucan such as cellulose (β-1 ,4-glucan), lentinan (β-1 0.6-glucan) and (β-1 ,3-glucan), pleuran (β-1, 6 and β-1 ,3-glucan) are isolated from species of fungi Basidiomycota include mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes).The purpose of thisresearch activity is to obtain beta-glucan compound that can be dissolved in water and in alkali derived from fungi Basidiomycota, i.e, Oyster mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes). The result of beta-glucan compared to characterize the resulting beta glucan that is molecular structure . The difference of beta glucan extraction is based on the differences in solubility of beta-glucan. Beta glucan could be water soluble and insoluble water.

scholarly journals Wound Healing Promotion by Hyaluronic Acid: Effect of Molecular Weight on Gene Expression and In Vivo Wound Closure

2021 ◽  
Vol 14 (4) ◽  
pp. 301
Author(s):  
Yayoi Kawano ◽  
Viorica Patrulea ◽  
Emmanuelle Sublet ◽  
Gerrit Borchard ◽  
Takuya Iyoda ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Weight ◽  
Wound Healing ◽  
Hyaluronic Acid ◽  
Healing Process ◽  
Dermal Fibroblasts ◽  
Water Soluble ◽  
Wound Healing Process ◽  
And Migration ◽  
Proliferation And Migration

Hyaluronic acid (HA) has been known to play an important role in wound healing process. However, the effect of molecular weight (MW) of exogenously administered HA on the wound healing process has not been fully understood. In this study, we investigated HA with different MWs on wound healing process using human epidermal keratinocytes and dermal fibroblasts. Cell proliferation and migration ability were assessed by water soluble tetrazolium (WST) assay and wound scratch assay. We examined the effect of HA addition in a full-thickness wound model in mice and the gene expression related to wound healing. Proliferation and migration of HaCaT cells increased with the increase of MW and concentration of HA. Interleukin (IL-1β), IL-8 and vascular endothelial growth factor (VEGF) as well as matrix metalloproteinase (MMP)-9 and MMP-13 were significantly upregulated by high molecular weight (HMW) HA in keratinocytes. Together with VEGF upregulation and the observed promotion of HaCaT migration, HA with the MW of 2290 kDa may hold potential to improve re-epithelialization, a critical obstacle to heal chronic wounds.

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

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