Exploring the thermomechanical properties of peroxide/co‐agent assisted thermoplastic vulcanizates through temperature scanning stress relaxation measurements

2021 ◽  
Author(s):  
Asit Baran Bhattacharya ◽  
Anagha M. Gopalan ◽  
Tuhin Chatterjee ◽  
Norbert Vennemann ◽  
Kinsuk Naskar
Keyword(s):  
Stress Relaxation ◽  
Thermomechanical Properties ◽  
Relaxation Measurements ◽  
Thermoplastic Vulcanizates ◽  
Temperature Scanning

Investigation of Un-Vulcanized Natural Rubber by Means of Temperature Scanning Stress Relaxation Measurements

2013 ◽  
Vol 718-720 ◽  
pp. 117-123 ◽  
Author(s):  
Miao Wu ◽  
Michael Heinz ◽  
Norbert Vennemann
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
Branch Points ◽  
Relaxation Spectra ◽  
Green Strength ◽  
Testing Method ◽  
Relaxation Measurements ◽  
Different Types ◽  
Temperature Scanning

Two different types of un-vulcanized natural rubber, air dried sheets (ADS) and SVR-3L block rubber, were investigated by a new testing method and the results are compared with other mechanical properties. It was found that green strength is strongly reduced if the sample is ther­mal­ly treated before testing. Presumably, the decrease of strength is caused by a decrease of branch points, mainly composed of phospholipids, which are linked to the a - terminal groups of the rubber molecules. The existence of two different types of branch points is indicated by relaxation spectra, obtained from temperature scanning stress relaxation (TSSR) measurements.

Investigation of modified SEBS-based thermoplastic elastomers by temperature scanning stress relaxation measurements

2005 ◽  
Vol 45 (11) ◽  
pp. 1498-1507 ◽  
Author(s):  
Aron Barbe ◽  
Klaus Bökamp ◽  
Claudia Kummerlöwe ◽  
Henner Sollmann ◽  
Norbert Vennemann ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Thermoplastic Elastomers ◽  
Relaxation Measurements ◽  
Temperature Scanning

scholarly journals Appraisal of the current standards for stress relaxation measurements in compression for rubbers

1986 ◽  
Vol 6 (2) ◽  
pp. 85-105 ◽  
Author(s):  
Arthur W. Birley ◽  
Kamal P. Fernando ◽  
Mohammed Tahir
Keyword(s):  
Stress Relaxation ◽  
Relaxation Measurements ◽  
Current Standards

Accelerated Heat-Aging Studies on Fluorosilicone Rubber

1975 ◽  
Vol 48 (5) ◽  
pp. 944-952 ◽  
Author(s):  
S. H. Kalfayan ◽  
R. H. Silver ◽  
A. A. Mazzeo
Keyword(s):  
Weight Loss ◽  
Stress Relaxation ◽  
Repeat Unit ◽  
Accelerated Aging ◽  
Basic Mechanism ◽  
Inert Atmosphere ◽  
Polymer Backbone ◽  
Aging Studies ◽  
Relaxation Measurements ◽  
Fluorosilicone Rubber

Abstract The accelerated aging of a vulcanizate of fluorosilicone rubber was studied by four methods: infrared spectroscopy, GPC, weight loss, and stress relaxation, with the object of gathering information pertinent to understanding the basic mechanism of its aging. No changes were observed in infrared spectra of the rubber aged in air up to 315°C although severe degradation took place, as evidenced by high weight loss and drastic change in the physical condition of the test samples. It was concluded that although the polymer degrades, there is no change detectable within the precision of the analytical methods in the structure of the repeat unit of the elastomer. The gel-permeation chromatogram of unheated rubber showed peaks at MW 450 000 (95%) and 630 (5%). The low-molecular-weight component is very likely the cyclic tetramer of λ,λ′,λ″-trifluoropropylmethylsiloxane, the principal monomer of the FVMQ used. Heat aging increased the concentration of the 630 MW component, but rate studies were prevented by complications resulting from solvent-induced rubber degradation. Rapid decrease in the MW of FVMQ, as found by GPC, indicated random scission in the polymer backbone, as opposed to ordered unzipping of the repeat unit. The same conclusion was reached from the effects of crosslink density on stress relaxation. Activation energies obtained from weight-loss measurements (104 kJ/mol) were lower than those obtained from stress-relaxation measurements, (150–155 kJ/mol), suggesting that the processes being measured in each case may not be the same. Chemical stress relaxation takes place more rapidly in the presence of air than in an inert atmosphere, and intermittent stress-relaxation measurements indicate that crosslinks form during thermal aging in air, their rate first increasing and then decreasing.

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