Stress-relaxation behavior of natural rubber/polystyrene and natural rubber/polystyrene/natural rubber-graft-polystyrene blends

2008 ◽  
Vol 108 (2) ◽  
pp. 904-913 ◽  
Author(s):  
R. Asaletha ◽  
P. Bindu ◽  
Indose Aravind ◽  
A. P. Meera ◽  
S. V. Valsaraj ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior

Effects of accelerator type on stress relaxation behavior and network structure of aged natural rubber/chloroprene rubber vulcanizates

2016 ◽  
Vol 49 (5) ◽  
pp. 381-396 ◽  
Author(s):  
Farzad A Nobari Azar ◽  
Murat Şen
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Network Structure ◽  
Structural Changes ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior ◽  
Rubber Blends ◽  
Chloroprene Rubber ◽  
Weather Changes ◽  
Behavior Network

Natural rubber/chloroprene rubber (NR/CR) blends are among the commonly used rubber blends in industry and continuously are exposed to severe weather changes. To investigate the effects of accelerator type on the network structure and stress relaxation of unaged and aged NR/CE vulcanizates, tetramethyl thiuram disulfide, 2-mercaptobenzothiazole, and diphenyl guanidine accelerators have been chosen to represent fast, moderate, and slow accelerator groups, respectively. Three batches have been prepared with exactly the same components and mixing conditions differing only in accelerator type. Temperatures scanning stress relaxation and pulse nuclear magnetic resonance techniques have been used to reveal the structural changes of differently accelerated rubber blends before and after weathering. Nonoxidative thermal decomposition analyses have been carried out using a thermogravimetric analyzer. Results indicate that there is a strong interdependence between accelerator type and stress relaxation behavior, network structure, cross-linking density, and aging behavior of the blends. Accelerator type also affects decomposition energy of the blends.

The Stress Relaxation of Sulfur Vulcanizates of Natural Rubber

1957 ◽  
Vol 30 (1) ◽  
pp. 42-53
Author(s):  
J. P. Berry
Keyword(s):  
Experimental Study ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
Oxygen Pressure ◽  
Relaxation Behavior ◽  
Two Stage ◽  
Stress Relaxation Behavior ◽  
Stage Process ◽  
Force Time ◽  
Effect Of Oxygen

Abstract An experimental study is reported of the stress relaxation behavior of sulfur vulcanizates of natural rubber maintained at constant extension. Of particular interest is the effect of oxygen pressure on the shape of the force-time curves, and the relaxation proceeding in absence of oxygen. The results are interpreted according to a two-stage process: (1) oxidation at the crosslinks and (2) scission of oxidized crosslinks.

Stress Relaxation of a Twaron®/Natural Rubber Composite

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
N. V. David ◽  
X.-L. Gao ◽  
J. Q. Zheng
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Rheological Model ◽  
Maxwell Model ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior ◽  
Generalized Maxwell Model ◽  
Rubber Composite ◽  
Long Time ◽  
Different Levels

The stress relaxation behavior of a Twaron CT709® fabric/natural rubber composite under a uniaxial constant strain is studied using three viscoelasticity models with different levels of complexity and a newly developed para-rheological model. The three viscoelasticity models employed are a one-term generalized Maxwell model (comprising one Maxwell element and an additional spring in parallel), a two-term generalized Maxwell model (including two Maxwell elements and an additional spring in parallel), and a four-parameter Burgers model. The values of the parameters involved in each model are extracted from the experimental data obtained in this study. The stress relaxation tests reveal that the stress starts to decay exponentially for a short duration and then continues to decrease linearly with time. It is found that the initial relaxation response of the composite is predicted fairly well by all of the four models, while the long-time stress relaxation behavior is more accurately predicted by the para-rheological model. The accuracy of each model in describing the stress relaxation behavior of the composite is quantitatively compared.

scholarly journals Stress-relaxation behavior in gels with ionic and covalent crosslinks

2010 ◽  
Vol 107 (6) ◽  
pp. 063509 ◽  
Author(s):  
Xuanhe Zhao ◽  
Nathaniel Huebsch ◽  
David J. Mooney ◽  
Zhigang Suo
Keyword(s):  
Stress Relaxation ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior ◽  
Covalent Crosslinks
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