Effects of Aging on the Fracture Behavior of Chlorinated Polyethylene and Chlorosulfonated Polyethylene

1994 ◽  
Vol 67 (4) ◽  
pp. 619-628 ◽  
Author(s):  
Mark E. Nichols ◽  
Robert A. Pett
Keyword(s):  
Carbon Black ◽  
Rate Constants ◽  
Arrhenius Behavior ◽  
Chlorinated Polyethylene ◽  
Chlorosulfonated Polyethylene ◽  
Elastomeric Materials ◽  
Tearing Energy ◽  
Aging Rates ◽  
Induction Times ◽  
Effects Of Aging

Abstract The thermoxidative aging behavior of chlorosulfonated polyethylene (CSM) and chlorinated polyethylene (CPE) vulcanizates has been investigated. Aging rates were determined by measuring isothermal oxidative induction times in a differential scanning calorimeter. Aging rates were also determined by measuring the decrease in the critical tearing energy of compounds as a function of aging time and temperature. Rate constants determined from induction time and tearing energy experiments displayed typical Arrhenius behavior. Below 240°C, rate constants from both experiments fell on the same line, suggesting that both experiments probe the same reaction. Activation energies for degradation of CSM and CPE were 88 and 108 kJ/mol respectively. Above 240°C, the mechanism of degradation changes with a corresponding change in activation energy to 190 and 232 kJ/mol for CSM and CPE, respectively. In the unaged state, the critical tearing energy of the carbon black-filled CPE compound is 50% higher than that of the carbon black-filled CSM compound. The rate of aging of CSM compound is approximately twice that of the CPE compound at equal temperatures. Decreases in tearing energy were attributed to additional crosslinking of the elastomer network. Combining oxidative induction times and critical tearing energy measurements may offer significant advantages in streamlining accelerated testing of elastomeric materials.

Development of adhesive ozone-resistant compositions based on chlorosulfonated polyethylene for elastomeric materials

2013 ◽  
Vol 6 (3) ◽  
pp. 207-209
Author(s):  
V. F. Kablov ◽  
N. A. Keibal ◽  
A. V. Bulgakov ◽  
O. V. Gorban’
Keyword(s):  
Chlorosulfonated Polyethylene ◽  
Elastomeric Materials

New, Highly Structured Carbon Black of the OMCARB Series for Reducing the Hysteresis in Rubber. Part 1. Features of the Structure and Properties of Carbon Black

2016 ◽  
Vol 43 (12) ◽  
pp. 17-22
Author(s):  
G.V. Moiseevskaya ◽  
G.I. Razd'yakonova ◽  
A.A. Petin ◽  
E.A. Strizhak
Keyword(s):  
Carbon Black ◽  
Chemical Properties ◽  
Morphological Characteristics ◽  
Structural Data ◽  
Structure And Properties ◽  
Elastomeric Materials ◽  
Rubber Part ◽  
Average Size ◽  
Branched Structure ◽  
And Chemical Properties

The aim of this work was to study the properties of carbon black CH85 of the OMCARB series and to compare them with the properties of standard carbon blacks N339 and N234. The morphological characteristics, the size distribution of the globules and aggregates, the surface area, the proportion of micropore area, the degree of branching of aggregates, and also the mechanical and chemical properties were measured and calculated. The average size of the aggregates of CH85 is greater than that of N339 and N234, and the aggregates have a more open and branched structure. The iodine adsorption by CH85 is practically the same as that by N339 and lower than that by N234. The low-hysteresis index calculated on the basis of structural data is much better for CH85. This opens up the possibility of using this type of carbon black for the development of elastomeric materials with low hysteresis.

scholarly journals “Transitivity”: A Code for Computing Kinetic and Related Parameters in Chemical Transformations and Transport Phenomena

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3478 ◽  
Author(s):  
Hugo G. Machado ◽  
Flávio O. Sanches-Neto ◽  
Nayara D. Coutinho ◽  
Kleber C. Mundim ◽  
Federico Palazzetti ◽  
...  
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
State Theory ◽  
Chemical Transformations ◽  
Graphical Interface ◽  
Arrhenius Behavior ◽  
Reaction Rate Constants ◽  
Kinetic And Thermodynamic Parameters ◽  
Data Documentation

The Transitivity function, defined in terms of the reciprocal of the apparent activation energy, measures the propensity for a reaction to proceed and can provide a tool for implementing phenomenological kinetic models. Applications to systems which deviate from the Arrhenius law at low temperature encouraged the development of a user-friendly graphical interface for estimating the kinetic and thermodynamic parameters of physical and chemical processes. Here, we document the Transitivity code, written in Python, a free open-source code compatible with Windows, Linux and macOS platforms. Procedures are made available to evaluate the phenomenology of the temperature dependence of rate constants for processes from the Arrhenius and Transitivity plots. Reaction rate constants can be calculated by the traditional Transition-State Theory using a set of one-dimensional tunneling corrections (Bell (1935), Bell (1958), Skodje and Truhlar and, in particular, the deformed ( d -TST) approach). To account for the solvent effect on reaction rate constant, implementation is given of the Kramers and of Collins–Kimball formulations. An input file generator is provided to run various molecular dynamics approaches in CPMD code. Examples are worked out and made available for testing. The novelty of this code is its general scope and particular exploit of d -formulations to cope with non-Arrhenius behavior at low temperatures, a topic which is the focus of recent intense investigations. We expect that this code serves as a quick and practical tool for data documentation from electronic structure calculations: It presents a very intuitive graphical interface which we believe to provide an excellent working tool for researchers and as courseware to teach statistical thermodynamics, thermochemistry, kinetics, and related areas.

Vulcanization of Elastomers. 40. Vulcanization of Natural Rubber and Synthetic Rubber with Sulfur in Presence of Sulfenamides. III

1965 ◽  
Vol 38 (1) ◽  
pp. 189-203 ◽  
Author(s):  
W. Scheele ◽  
J. Helberg
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
Rate Constants ◽  
Sulfur Concentration ◽  
Kcal Mole ◽  
Synthetic Rubber ◽  
Chemical Constitution ◽  
Induction Times ◽  
Kinetics Of

Abstract Vulcanization of natural rubber with sulfur was studied in presence of six sulfenamides, to determine the effect of the chemical constitution of the sulfenamide on sulfur decrease and on crosslinking. The results can be condensed as follows: (1) The kinetics of sulfur disappearance is in every respect qualitatively independent of the chemical constitution of the sulfenamide. (2) For the sulfenamides investigated, the smallest and largest rate constants for sulfur decrease differed only by a factor of two. (3) Greater differences are encountered in the induction times for sulfur decrease and for crosslinking. The latter are notably longer than those for sulfur disappearance. (4) The same activation energy, 23 kcal/mole, is derived from the temperature dependence of the induction times for all the sulfenamides. (5) The dissociation of sulfenamides in solution and their reaction with mercaptobenzothiazole were investigated further. The results provide the basis for a proposed reaction mechanism, which is presented in detail and can account for a number of the features typical of sulfenamide-accelerated vulcanization. (6) The drop in sulfur concentration goes at practically the same rate, if one introduces, instead of N, N-dicyclohexyl-2-benzothiazolesulfenamide, the corresponding ammonium mercaptide in equimolar concentration.

Étude théorique des réactions d'abstraction d'hydrogène , avec R, X≡H, CH3, NH2,OH et F

1985 ◽  
Vol 63 (7) ◽  
pp. 1447-1456 ◽  
Author(s):  
Georges Leroy ◽  
Michel Sana ◽  
Anne Tinant
Keyword(s):  
Transition State ◽  
Rate Constants ◽  
Transition State Theory ◽  
Hydrogen Abstraction ◽  
State Theory ◽  
Arrhenius Behavior ◽  
Activation Barriers ◽  
Empirical Procedure ◽  
Semi Empirical ◽  
Theory And Experiment

Hydrogen abstraction reactions [Formula: see text] with R, X≡H, CH3, NH2,OH, and F have been studied at the abinitio 6-31G – UHF level. However, energetic properties were computed at the CI level. Rate constants and Arrhenius parameters have been obtained using the transition state theory formalism with Eckart's tunneling correction. The discrepancy between theoretical and experimental results led us to elaborate a semi-empirical procedure to calculate activation barriers, in which the bonds R—H and X—H are represented by Morse curves. Thus, the agreement between theory and experiment is much better. Moreover, the results obtained by this procedure demonstrate the non-Arrhenius behavior of all the reactions under consideration and allow us to rationalize a large number of experimental facts.

scholarly journals The effect of gamma radiation on the ageing of sulfur cured NR/CSM and NBR/CSM rubber blends reinforced by carbon black

2009 ◽  
Vol 15 (4) ◽  
pp. 291-298 ◽  
Author(s):  
Gordana Markovic ◽  
Milena Marinovic-Cincovic ◽  
Vojislav Jovanovic ◽  
Suzana Samardzija-Jovanovic ◽  
Jaroslava Budinski-Simendic
Keyword(s):  
Carbon Black ◽  
Average Particle Size ◽  
Accelerated Ageing ◽  
Average Particle ◽  
Aromatic Rings ◽  
Rubber Blends ◽  
Rubber Blend ◽  
Infrared Measurements ◽  
Elastomeric Materials ◽  
Elastomeric Composites

In this work the effect of the ?-radiation dose on ageing of carbon black reinforced elastomeric materials was studied. The compounds based on natural rubber/chlorosulfonated rubber blend (NR/CSM) and butadiene acrylonitrile rubber/chlorosulfonated rubber blend (NBR/CSM) (50:50, w/w) with different loadings (0, 20, 40, 50, 60, 80 and 100 phr) of the filler with the average particle size of 40 nm were cured by sulfur. The obtained elastomeric composites were subjected to radiation doses (100, 200, 300 and 400 kGy) in the presence of oxygen. The changes of material mechanical properties were estimated after radiation accelerated ageing. By using Fourier transform infrared measurements (ATR-FTIR) it was assessed that after exposure to doses of 100 kGy alcohols, ethers, lactones, anhydrides, esters and carboxylic acids are formed in materials. The formation of shorter polyene sequences and aromatic rings in aged samples are assumed on the basis of the obtained spectra.

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