ChemInform Abstract: SINGLE MOLECULE GAS-PHASE POLYMERIZATION KINETICS OF VINYL ACETATE. NON-STEADY MEASUREMENTS

1985 ◽  
Vol 16 (18) ◽  
Author(s):  
H. REISS ◽  
M. A. CHOWDHURY
Keyword(s):  
Gas Phase ◽  
Vinyl Acetate ◽  
Single Molecule ◽  
Polymerization Kinetics ◽  
Gas Phase Polymerization ◽  
Kinetics Of

The Effect of Reactor Conditions on High-Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

2018 ◽  
Vol 12 (4) ◽  
pp. 1700063 ◽  
Author(s):  
Aarón J. Cancelas ◽  
Lanti Yang ◽  
Robin Girod ◽  
Jos de Heer ◽  
Ralf Kleppinger ◽  
...  
Keyword(s):  
Gas Phase ◽  
Polymerization Kinetics ◽  
High Impact ◽  
Gas Phase Polymerization

Impact of catalyst injection conditions on the gas phase polymerization of propylene

2017 ◽  
Vol 2 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Aarón J. Cancelas ◽  
Vincent Monteil ◽  
Timothy F. L. McKenna
Keyword(s):  
Gas Phase ◽  
Initial Temperature ◽  
Flow Reactor ◽  
Mineral Oil ◽  
Polymerization Kinetics ◽  
Current Work ◽  
Stopped Flow ◽  
Temperature Profiles ◽  
Polymer Properties ◽  
Gas Phase Polymerization

In the current work, gas phase propylene polymerizations were performed on ZN catalysts in a stopped flow reactor to understand the effect that the injection conditions (dry, as received, or wetted with a commercially available paraffinic mineral oil) have on initial temperature profiles, nascent polymer properties, and polymerization kinetics.

scholarly journals The photochemical polymerization of methyl methacrylate vapour

1937 ◽  
Vol 163 (915) ◽  
pp. 511-542 ◽  
Keyword(s):  
Gas Phase ◽  
Chain Reactions ◽  
The Past ◽  
Whole Process ◽  
Scant Attention ◽  
Initiation Reaction ◽  
Photochemical Polymerization ◽  
Gas Phase Polymerization ◽  
Kinetics Of ◽  
Specific Inhibitors

It is rather a remarkable fact th a t although the study of polymerization reactions has increased enormously within the past few years, gas-phase polymerization has received scant attention. By performing such experiments in the gas phase all the exact technique of gas kinetics is at once available to unravel the complex sequence of collision types which make up a polymeric reaction. Once the essential features of the reaction are discovered, it is in many cases a comparatively simple matter to control these over wide limits. It has long been recognized that polymerization processes are chain reactions. If the reaction is initiated thermally, then the observed kinetics of the overall reaction may become rather complicated, so that it is difficult to calculate the absolute velocities of the reactions comprising the whole process. As in ordinary chain reactions, this difficulty can be overcome by adopting photochemical methods of controlling the initiation reaction. Having started the growth of the polymer the velocity of growth is then dependent primarily on the inherent properties of the molecule but may be modified by altering gas pressure and temperature. The termination reaction may be one of a number of types and hence control may or may not be possible. In certain reactions control can often be exercised in one direction, namely, in limiting the growth of the polymer by the introduction of specific inhibitors.

The mechanism of the anionic coordination polymerization of isoprene

1980 ◽  
Vol 45 (9) ◽  
pp. 2391-2399 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Chromatographic Method ◽  
Initial Period ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Coordination Polymerization ◽  
Initial Concentration ◽  
The Cross ◽  
Gas Chromatographic Method ◽  
Kinetics Of

The polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene with butyllithium as the initiator was investigated by the gas chromatographic method. After completion of the initial period of the reaction, its order with respect to the initial concentration of initiator is negative at the concentrations of the latter between 0.01 and 0.25 mol/l, and positive at higher concentrations. A reaction scheme has been suggested with respect to the "cross" association of butyllithium and of the "living" oligoisoprene.

The effect of electrondonors on the polymerization kinetics of isoprene

1980 ◽  
Vol 45 (12) ◽  
pp. 3338-3346
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Induction Period ◽  
Ethyl Ether ◽  
Reaction Order ◽  
Propagation Rate ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Polymerization Rate ◽  
Constant Concentration ◽  
Initial Concentration ◽  
Kinetics Of

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

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