scholarly journals Optimisation of Graft Copolymerisation of Fibres from Banana Trunk

2012 ◽  
Vol 9 (1) ◽  
pp. 373-380 ◽  
Author(s):  
Richard Mpon ◽  
Maurice K. Ndikontar ◽  
Hyppolite N. Ntede ◽  
J. Noah Ngamveng ◽  
Alain Dufresne ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Nitric Acid ◽  
Plant Material ◽  
Average Diameter ◽  
Ethyl Acrylate ◽  
Single Fibre ◽  
Ion Concentration ◽  
Reaction Conditions ◽  
Ceric Ion ◽  
Acid Process

Sheets from banana trunks were opened out and dried for several weeks in air. Pulp was obtained by the nitric acid process with a yield of 37.7% while fibres were obtained according to the modified standard Japanese method for cellulose in wood for pulp (JIS 8007) with a yield of 65% with respect to oven dried plant material. Single fibre obtained by the JIS method had an average diameter of 11.0 μm and Young's modulus, tensile strength and strain at break-off 7.05 GPa, 81.7 MPa and 5.2% respectively. Modification of the fibres was carried out by grafting ethyl acrylate in the presence of ammonium nitrate cerium(IV). Optimisation of the copolymerisation reaction conditions was studied by measuring the rate of conversion, the rate of grafting and the grafting efficiency. The results showed that at low values of ceric ion concentration (0.04 M), at ambient temperature, after three hours and at a concentration of 0.2 M ethyl acrylate, maximum values of the parameters cited were obtained.

Aqueous polymerization of ethyl acrylate initiated by ceric ion-reducing agent systems in nitric acid medium

2001 ◽  
Vol 50 (3) ◽  
pp. 354-359 ◽  
Author(s):  
G?V Ramana Reddy ◽  
A Muthulakshmi ◽  
C Dulcy Evangelin ◽  
P Rajendran
Keyword(s):  
Nitric Acid ◽  
Acid Medium ◽  
Ethyl Acrylate ◽  
Reducing Agent ◽  
Nitric Acid Medium ◽  
Agent Systems ◽  
Aqueous Polymerization ◽  
Ceric Ion

Immobilized Recombinant Chitinase and its Inhibition Effect on Botrytis Cinerea

2014 ◽  
Vol 936 ◽  
pp. 674-680
Author(s):  
Na Zhang ◽  
Rui Xiang Yan ◽  
Wen Qiang Guan
Keyword(s):  
Reduction Method ◽  
Average Diameter ◽  
Thermal Reduction ◽  
Gray Mold ◽  
Magnetic Carrier ◽  
Reaction Conditions ◽  
Recombinant Chitinase ◽  
Crude Enzyme Solution ◽  
Infrared Spectrometer

To isolate recombinant chitinase quickly and boost its anti-fungi activities in vitro, functional magnetic nanometer carrier was used to immobilize recombinant chitinase from the crude enzyme solution and immobilized recombinant chitinase was applied to test whether it would inhibit the growth of gray mold from fruits. In this study, the carboxyl magnetic carrier was produced by solvent thermal reduction method and characterized by scanning electron microscope (SEM) and fourier transform infrared spectrometer (FTIR). Then, the carboxyl magnetic carrier activated by EDC/NHS was applied to immobilize recombinant chitinase and the immobilization efficiency was investigated by quantitative analysis. To obtain the highest immobilization efficiency, reaction conditions were optimized through combining different pH, temperature and reaction period. The results show that the surface of magnetic carrier was successfully carboxyl and the average diameter was 200nm. The immobilization efdiciency could reach the peak 64.43% after 7h reaction at the condition of pH 6 and 25°C. It also shows that immobilized recombinant chitinase can significantly inhibit the growth of gray mold isolated from table grape compared with the enzyme without immobilization with magnetic nanometer carrier.

Effect of Heat Setting Methods on Structures and Properties of High Strength Polyvinyl Alcohol Fibre

2015 ◽  
Vol 815 ◽  
pp. 643-648
Author(s):  
Yin Zhu ◽  
Jiong Xin Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polyvinyl Alcohol ◽  
Setting Time ◽  
High Strength ◽  
Single Fibre ◽  
X Ray Diffraction ◽  
Heat Setting ◽  
Heat Treated ◽  
Setting Process

The effect of heat setting methods on the structures and mechanical properties of high strength polyvinyl alcohol (PVA) fibre is studied in this article. The microstructure and mechanical properties of heat treated PVA fibre is investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and single fibre electronic tensile strength tester. Results show that the heat setting method with constant tension is a good heat setting method which can largely enhance the tensile strength of PVA fibre. During the heat setting process, the mechanical properties of PVA fibre are greatly affected by the temperature, tension and setting time. When the temperature is 220°C, tension is 5cN/dtex and setting time is 90sec, the tensile strength of PVA fibre increases from 12.0cN/dtex to 16.4cN/dtex in compare with the PVA fibre without heat setting

Thin Films Grown on Silicon Surfaces by Excess Nitric Acid Process

1965 ◽  
Vol 112 (12) ◽  
pp. 1251 ◽  
Author(s):  
William B. Glendinning ◽  
Sidney Marshall ◽  
Albert Mark
Keyword(s):  
Thin Films ◽  
Nitric Acid ◽  
Silicon Surfaces ◽  
Acid Process

Minimisation of exergy losses in mono high pressure nitric acid process

2015 ◽  
Vol 17 (2) ◽  
pp. 192 ◽  
Author(s):  
Rajubhai K. Mewada ◽  
Samir C. Nimkar
Keyword(s):  
High Pressure ◽  
Nitric Acid ◽  
Acid Process ◽  
Exergy Losses

The Synthesis of Zinquin Ester and Zinquin Acid, Zinc(II)-Specific Fluorescing Agents for Use in the Study of Biological Zinc(II)

1996 ◽  
Vol 49 (5) ◽  
pp. 561 ◽  
Author(s):  
IB Mahadevan ◽  
MC Kimber ◽  
SF Lincoln ◽  
ERT Tiekink ◽  
AD Ward ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Crystal Structures ◽  
Electrophilic Substitution ◽  
Ethyl Acrylate ◽  
Heck Coupling ◽  
Ethyl Bromoacetate ◽  
Reaction Conditions ◽  
Bromo Derivative ◽  
Boron Tribromide

The syntheses of Zinquin ester [ethyl [2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetate] and the corresponding acid, both of which are zinc(II)-specific fluorophores , are described. 6-Methoxy-2-methyl-8-(p- tolylsulfonylamino ) quinoline (2) can be demethylated , with boron tribromide, to form either the expected phenol or a mixture of the phenol and the corresponding 5-bromo derivative depending upon the reaction conditions. These compounds react with ethyl bromoacetate to give the corresponding esters, as well as the 5-ethoxycarbonyl derivative formed by electrophilic substitution. Halogenation of the sulfonamide (2) occurs readily at the 5-position. The 5-iodo product undergoes a Heck coupling with ethyl acrylate . The crystal structures of ethyl [5-ethoxycarbonylmethyl-2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetate and [5-carboxymethyl-2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetic acid are described.

scholarly journals Characterizing Distributions of Tensile Strength and Crack Precursor Size to Evaluate Filler Dispersion Effects and Reliability of Rubber

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 203 ◽  
Author(s):  
Christopher G. Robertson ◽  
Lewis B. Tunnicliffe ◽  
Lawrence Maciag ◽  
Mark A. Bauman ◽  
Kurt Miller ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Average Diameter ◽  
Strength Distribution ◽  
Glass Beads ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Failure Distribution ◽  
Filler Dispersion ◽  
Control Compound ◽  
Styrene Butadiene

Undispersed filler agglomerates or other substantial inclusions/contaminants in rubber can act as large crack precursors that reduce the strength and fatigue lifetime of the material. To demonstrate this, we use tensile strength (stress at break, σb) data from 50 specimens to characterize the failure distribution behavior of carbon black (CB) reinforced styrene-butadiene rubber (SBR) compounds. Poor mixing was simulated by adding a portion of the CB late in the mixing process, and glass beads (microspheres) with 517 μm average diameter were introduced during milling to reproduce the effects of large inclusions. The σb distribution was well described with a simple unimodal Weibull distribution for the control compound, but the tensile strengths of the poor CB dispersion material and the compounds with the glass beads required bimodal Weibull distributions. For the material with the lowest level of glass beads—corresponding to less than one microsphere per test specimen—the bimodal failure distribution spanned a very large range of σb from 13.7 to 22.7 MPa in contrast to the relatively narrow σb distribution for the control from 18.4 to 23.8 MPa. Crack precursor size (c0) distributions were also inferred from the data, and the glass beads introduced c0 values in the 400 μm range compared to about 180 μm for the control. In contrast to σb, critical tearing energy (tear strength) was unaffected by the presence of the CB agglomerates and glass beads, because the strain energy focuses on the pre-cut macroscopic crack in the sample during tear testing rather than on the microscopic crack precursors within the rubber. The glass beads were not detected by conventional filler dispersion measurements using interferometric microscopy, indicating that tensile strength distribution characterization is an important complementary approach for identifying the presence of minor amounts of large inclusions in rubber.

Rate of Deposition of Latex on Porous Molds

1931 ◽  
Vol 4 (3) ◽  
pp. 437-444
Author(s):  
H. W. Greenup
Keyword(s):  
Tensile Strength ◽  
South America ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Latex Particles

Abstract The effects of pressure, rubber concentration of latex, temperature, and hydrogen-ion concentration upon the rate of deposition of latex on porous molds are described. Pressure, rubber concentration, and temperature were found to be negligible factors in comparison with hydrogen-ion concentration. By adjusting the pH of the latex to 6.1 it was found possible to obtain aggregation of the latex particles and a marked increase in rate of deposition. THE manufacture of rubber articles by dipping porous forms in latex was first described by Condamine (5). He reported to the Paris Academy in 1736 that the natives in South America made such articles as shoes and bottles, using clay molds which, after drying of the deposited layer, were shattered and removed. The idea of making articles by a process of this sort, instead of by coagulating the latex, milling, and then shaping the milled rubber, appeals to the imagination. Increased tensile strength and improved aging have been claimed (10) for articles made directly from latex, and their remarkable resistance to tear, obtained under certain conditions, is well known.

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