scholarly journals Effects of Grinding Methods on Physicochemical Properties of Crude Polysaccharides from Phellinus baumii

2019 ◽  
Vol 78 ◽  
pp. 02004
Author(s):  
Tingting Li ◽  
Yan Yang ◽  
Linjun Chen ◽  
Wanling Yang
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Raw264.7 Cells ◽  
Fruiting Bodies ◽  
Phellinus Baumii ◽  
Grinding Technique ◽  
Molecular Weight Fractions

The physicochemical properties of Phellinus baumii polysaccharides extracted from the fruiting bodies by different grinding methods were studied in this paper. Compared with ordinary grinding methods, superfine grinding technology exerts significantly higher yields of crude polysaccharides, polysaccharide contents and β-Glucan contents of six samples. HPSEC-MALLS- RI analysis shows the molecular weight distribution of P.baummii crude polysaccharides, which indicates superfine grinding technique generates higher molecular weight fractions and larger polydispersities. The 6 kinds of crude polysaccharides have obvious effects on NO generation of RAW264.7 cells, which indicated that crude polysaccharides from P.baumii may have some immune-enhancing effects. Meanwhile, CW30 and FP30 show the best immune enhancing effects. However, CW50 and CW70 exert weaker immune-enhancing effects compared with FP50 and FP70.

Characterization of Elution Chromatography Fractions from CIS-Polybutadiene by GPC

1970 ◽  
Vol 43 (6) ◽  
pp. 1439-1450 ◽  
Author(s):  
W. V. Smith ◽  
S. Thiruvengada
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Low Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Log Normal ◽  
Analytical Fractionation ◽  
Molecular Weight Fractions ◽  
Elution Chromatography

Abstract A preparative fractionation of about 23 g of a commercial cis-polybutadiene rubber is described. The method employed was a solvent elution chromatographic method with very little temperature gradient. The molecular weight distributions of the fractions obtained were determined by an analytical fractionation of 20 mg of polymer. The method was similar to the preparative fractionation and involved solvent elution chromatography. The fractions obtained were assayed for quantity, molecular weight, and molecular weight distribution by GPC. The low molecular weight fractions of the preparative fractionation had molecular weight distributions which could be closely approximated by two log normal distributions, the low molecular weight component having the narrower width. The ratio of weight to number average molecular weight was found to be about 1.1 for these samples. The higher molecular weight fractions could also be approximated by two log normal distributions; however, in these fractions the low molecular weight component had a very broad distribution but constituted only a small portion of the sample. The widths of the GPC curves of the fractions correlate satisfactorily with the molecular weight distributions found by the analytical refractionations. The GPC width is a sensitive criterion of the width of the molecular weight distribution even when only two columns are used. It is felt that the analytical fractionation procedure presented gives more detailed information on the molecular weight distribution than is easily obtainable from an ordinary GPC curve.

THE FRACTIONATION OF POLYTHENE

1961 ◽  
Vol 39 (10) ◽  
pp. 1888-1891 ◽  
Author(s):  
W. R. Blackmore ◽  
W. Alexander
Keyword(s):  
Molecular Weight ◽  
Distribution Function ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Negative Binomial ◽  
Average Molecular Weight ◽  
Weight Average Molecular Weight ◽  
Log Normal ◽  
Molecular Weight Fractions ◽  
Good Agreement

An apparatus is described for fractionating large quantities (400 g) of polythene into five roughly equal fractions using a fractional precipitation technique. Application of this method of fractionation to a linear polythene has shown that the width of the molecular-weight distribution of the successive fractions decreases as the fractionation proceeds. Consequently, the initial high-molecular-weight fractions require refractionation to produce equally narrow distributions in them as are found in later fractions. Good agreement is obtained with the experimentally determined values of the number-average and weight-average molecular weight for the parent polymer when the measured values of Mn and Mw for each fraction are used to calculate the values for the parent. The differential molecular-weight distribution function of the parent polymer was calculated on a Bendix G-15 computer from the data for the fractions by using the weight, number-average and weight-average molecular weight, measured for each fraction in conjunction with an assumed log-normal or negative binomial molecular-weight distribution function in each fraction.

Molecular Weight Distribution of Polystyrene and of Butadiene-Styrene Copolymers Prepared in Emulsion Systems

1970 ◽  
Vol 43 (6) ◽  
pp. 1424-1438
Author(s):  
C. A. Uraneck ◽  
J. E. Burleigh
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Homologous Series ◽  
Degree Of Branching ◽  
Styrene Copolymers ◽  
Divinyl Benzene ◽  
Emulsion Systems ◽  
Molecular Weight Fractions ◽  
Butadiene Styrene

Abstract Polystyrene and butadiene—styrene copolymers (SBR) were parepared in emulsion systems with a homologous series of commercial mercaptan modifiers. The molecular weight distribution (MWD) of the sets of polymers changed in a consistant manner when the regulating index of the mercaptan was relatively low. However the shape of the MWD curves appeared distorted in comparison to theoretical curves when the modifier depleted rapidly and when divinyl-benzene was present in the system. The divergence from the theoretical curve is attributed to a higher degree of branching in the high molecular weight fractions. Differences in MWD of SBR made with n- and tert-dodecyl mercaptans was marked. Notable differences were also found for SBR 1500 samples from the industry at random, but only slight differences were seen in a set of SBR 1503 samples. This study shows how the MWD of polymers prepared in emulsions can be varied simply by use of modifiers with different regulating indexes.

Fractionation of woodmeal by prehydrolysis and thermal organosolv. Alkaline depolymerization, chemical functionality, and molecular weight distribution of recovered lignins and their fractions

1993 ◽  
Vol 71 (6) ◽  
pp. 779-789 ◽  
Author(s):  
Ronald W. Thring ◽  
Esteban Chornet ◽  
Ralph P. Overend
Keyword(s):  
Molecular Weight ◽  
Solvent Extraction ◽  
Phenolic Compounds ◽  
Nmr Spectroscopy ◽  
Elemental Composition ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Side Chain ◽  
Molecular Weight Fractions ◽  
C Nmr

Thermal organosolv glycol lignins and their fractions have been characterized by means of elemental composition, molecular weight distribution, and 1H and 13C NMR spectroscopy. Fractionation of each lignin by sequential solvent extraction produced fractions of increasing molecular weight and polydispersity. Structures in the highest molecular weight fractions were found to be linked by a high proportion of β-O-4 type bonds, whilst the lowest molecular weight fractions consisted of a high content of saturated aliphatic side-chain structures. A noticeable difference in the content of carbohydrate contaminants in both starting lignins indicated the formation of relatively stable lignin–carbohydrate complexes, especially in the lignin recovered from pretreated wood. In addition, depolymerization of the lignins and their fractions to monomeric compounds was explored using alkaline hydrolytic and nitrobenzene oxidative routes. The highest molecular weight fractions from each lignin were identified as the best candidates for production of useful monomeric phenolic compounds.

Preparation and Physicochemical Properties of Concrete Slump-Loss Resistance Agent for Small Slump

2010 ◽  
Vol 168-170 ◽  
pp. 2158-2164
Author(s):  
Guo Rong Duan ◽  
Guo Hong Huang ◽  
Xin Wang ◽  
Ying Gong
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Molecular Weight Distribution ◽  
Cement Paste ◽  
Weight Distribution ◽  
Synthesis Method ◽  
Retention Performance ◽  
Wide Range ◽  
Loss Resistance ◽  
Gel Permeation

By the application of esterification-polymerization two-step synthesis method, comb-shaped polycarboxylate slump-loss resistance agent XBT for small slump concrete is prepared by controlling ester ratio. The experimental results of concrete and fresh cement paste indicate that XBT has excellent function of plasticity retention in small slump concrete. The experiment of gel permeation liquid chromatogram shows that XBT has wide range of molecular weight distribution, which may be the source of fine plasticity retention performance in the small slump concrete. The combined experiment between ultraviolet and conductivity indicates that there is strong adsorptive action between XBT and Ca2+, and their adsorptive characteristics may be closely related to the plasticity retention properties.

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)

2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe
Keyword(s):  
Molecular Weight ◽  
Protein Content ◽  
Ammonium Sulfate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Protease Activity ◽  
Protein Concentration ◽  
Temperature Stability ◽  
Partial Purification ◽  
Ammonium Sulfate Precipitation

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 

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