Mechanism and kinetics of emulsion copolymerization of vinylidene chloride—Critical conversion at the end of interval 2 and rate of polymerization

1993 ◽  
Vol 30 (4) ◽  
pp. 441-444 ◽  
Author(s):  
Zaizhang Yu ◽  
Hongbing Jia ◽  
Bogeng Li ◽  
Baofang Li
Keyword(s):  
Emulsion Copolymerization ◽  
Vinylidene Chloride ◽  
Rate Of Polymerization ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Critical Conversion

The mechanism and kinetics of the heterogeneous polymerization of vinyl monomers II. The benzoyl peroxide catalyzed polymerization of vinylidene chloride

1953 ◽  
Vol 218 (1133) ◽  
pp. 149-154 ◽  
Keyword(s):  
Benzoyl Peroxide ◽  
Reaction Rate ◽  
Transfer Reactions ◽  
Vinyl Monomers ◽  
Vinylidene Chloride ◽  
Heterogeneous Polymerization ◽  
Rate Of Polymerization ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Active Centres

The polymerization of vinylidene chloride initiated with from 0.02 to 1.0 mol. % benzoyl peroxide has been studied at temperatures from 47 to 75° C. In all cases the rate of polymerization was found to increase throughout the first 30% polymerization. The reaction rate when compared at equal extents of conversion was found to vary as the square root of the benzoyl peroxide concentration. In the presence of tetrahydrofuran the rate of polymerization remained constant during the early stages of the reaction. These results can be explained by the mechanism put forward in part I, namely, that active centres undergo transfer reactions with ‘dead’ polymer resulting in the formation of immobile polymer centres which continue to grow and are finally terminated by chain transfer reactions with monomer.

Kinetics of Inverse Emulsion Copolymerization of Dimethyl Diallyl Ammonium Chloride and Acrylamide

2014 ◽  
Vol 989-994 ◽  
pp. 348-351 ◽  
Author(s):  
Xiao Na Wang ◽  
Ren Zhi Zhang ◽  
Ni Sha Jin
Keyword(s):  
Activation Energy ◽  
Intrinsic Viscosity ◽  
Initial Temperature ◽  
Tween 80 ◽  
Polymerization Rate ◽  
Emulsion Copolymerization ◽  
Inverse Emulsion ◽  
Rate Of Polymerization ◽  
Span 80 ◽  
Kinetics Of

Inverse emulsion copolymerization of DMDAAC with AM has been investigated by the dilatometer technique using the mixture of Span-80 and Tween-80 as the composite emulsifier and 2,2’-azobis (2-methylpropionconidine) dihydro chloride as the initiator. In inverse emulsion copolymerization, the influences of the concentrations of monomers, emulsifier and initiator and initial temperature on polymerization rate and the intrinsic viscosity of polymer have been examined. Its kinetics can be expressed as,. The overall activation energy for the rate of polymerization was determined with a dilatometer as 20.33 kJ/mol over the temperature range 35-55°C.

The mechanism and kinetics of the heterogeneous polymerization of vinyl monomers III. The benzoyl peroxide catalyzed copolymerization of vinyl and vinylidene chlorides

1953 ◽  
Vol 218 (1133) ◽  
pp. 155-163 ◽  
Keyword(s):  
Benzoyl Peroxide ◽  
Vinyl Chloride ◽  
Vinyl Monomers ◽  
Percentage Increase ◽  
Vinylidene Chloride ◽  
Minimum Value ◽  
Heterogeneous Polymerization ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A study has been made of the copolymerization of vinyl chloride and vinylidene chloride in the presence of 0.75 mol. % Bz 2 O 2 at 47° C. The rate of copolymerization decreases to a minimum value of about one-quarter of the rate for the pure monomers, for a mixture containing about 35 to 40 mol. % vinylidene chloride. Throughout the whole range of monomer compositions the rate increases during the reaction, but the percentage increase in rate varies with the solubility of the copolymer formed. This increase has been ascribed to the precipitation of solid copolymer phase from the reacting system.

Oil extraction from the sunflower seeds, mechanism and kinetics of the process

2020 ◽  
Vol 3 (1) ◽  
pp. 155-160
Author(s):  
Ye. M. Semenyshyn ◽  
◽  
V. M. Atamanyuk ◽  
O. Ya. Dobrovetska ◽  
T. I. Rymar ◽  
...  
Keyword(s):  
Oil Extraction ◽  
Sunflower Seeds ◽  
Mechanism And Kinetics ◽  
Kinetics Of

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

Mechanism and Kinetics of the Hydrogen Failure of Thermoelectric Materials during Water Electrolysis

2020 ◽  
Vol 2020 (10) ◽  
pp. 1102-1115
Author(s):  
M. A. Korzhuev ◽  
I. V. Katin ◽  
M. A. Kretova ◽  
E. S. Avilov
Keyword(s):  
Thermoelectric Materials ◽  
Water Electrolysis ◽  
Mechanism And Kinetics ◽  
Kinetics Of

Spectrocoulometry – a new spectro-electrochemical technique

1987 ◽  
Vol 52 (6) ◽  
pp. 1386-1396 ◽  
Author(s):  
Ján Mocák ◽  
Michal Németh ◽  
Mieczyslaw Lapkowski ◽  
Jerzy W. Strojek
Keyword(s):  
Optical Probe ◽  
Optical Signal ◽  
Open Circuit ◽  
Electrochemical Technique ◽  
Kinetics Of Oxidation ◽  
Hydrolytic Reaction ◽  
Experimental Errors ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A spectrocoulometric macrocell with a direct-view optical probe was designed and constructed, where the optical signal is transferred by light-conducting glass or quartz fibres permitting to work at wavelengths above 410 or 300 nm. The method of measurement on the proposed equipment is described; it was tested in the study of the mechanism and kinetics of oxidation of Fe(bipy)32+ ions (bipy = 2,2'-bipyridyl) with the use of potentiostatic coulometric electrolysis with open-circuit relaxation at a suitable time. The primary product of electrolysis, Fe(bipy)33+, undergoes a follow-up hydrolytic reaction with the formation of a binuclear complex. The rate constant of the reaction of the first order involves the contributions, kBi, from all bases present in solution; the corresponding values for H2O, OH-, bipy, and CH3COO- ions at a ionic strength 0·5 mol dm-3 and 25 °C were determined as kOH = (5·0 ± 0·6) . 105 mol-1 dm3 s-1, kbipy = (1·3 ± 0·2) . 10-1 mol-1 dm3 s-1, kAc = (5·8 ± 1·0) . 10-2 mol-1 dm3 s-1, and kH2O is not significant with respect to experimental errors.

New highly efficient coulometric cell with homogenous potential distribution on the working electrode

1986 ◽  
Vol 51 (3) ◽  
pp. 636-642
Author(s):  
Michal Németh ◽  
Ján Mocák
Keyword(s):  
Chemical Reactions ◽  
Potential Distribution ◽  
Anaerobic Conditions ◽  
Highly Efficient ◽  
Working Electrode ◽  
Constant Potential ◽  
Quantitative Analyses ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A highly efficient coulometric cell was designed and constructed, ensuring a constant potential over the whole surface of the working electrode and suitable for very rapid electrolysis. It consists of concentric cylindrical Teflon parts; also the working and auxiliary electrodes are cylindrical and concentric. Electrolysis can be carried out under anaerobic conditions. Functioning of the cell was tested on the oxidation of hexacyanoferrate(II) and chlorpromazine and reduction of hexacyanoferrate(III). The new cell is suitable for routine quantitative analyses and in studying the mechanism and kinetics of moderately rapid chemical reactions.

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