scholarly journals Relationship between stress relaxation behavior and thermal stability of natural rubber vulcanizates

Polímeros ◽  
2020 ◽  
Vol 30 (2) ◽  
Author(s):  
Nabil Hayeemasae ◽  
Abdulhakim Masa
Keyword(s):  
Thermal Stability ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior ◽  
Natural Rubber Vulcanizates ◽  
Thermal Stability Of

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.

Influence of the Type of Alkylamine Organic Modifiers on Thermal Mechanical Behavior and other Related Properties of Natural Rubber/Clay Nanocomposites

2013 ◽  
Vol 844 ◽  
pp. 217-220 ◽  
Author(s):  
Uraiwan Sookyung ◽  
Woothichai Thaijaroen ◽  
Norbert Vennemann ◽  
Charoen Nakason
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
The Other ◽  
Clay Nanocomposites ◽  
Organic Modifier ◽  
Organic Modifiers ◽  
Different Types ◽  
Thermal Stability Of

Sodium-montmorillonite (Na-MMT) nanoclay was modified with different types of alkylamine organic modifier including primary and quaternary alkylamines. Influence types of alkylamine on properties of natural rubber/clay nanocomposites was investigated. It was found that organoclays caused improvement of mechanical properties of natural rubber, and accelerated vulcanization reaction with higher degree of crosslinking. In addition, organoclay modified with quaternary alkylamine showed significance cure reversion phenomenon which caused reduction of thermal stability. On the other hand, primary alkylamine modified nanoclay caused improvement of thermal stability of natural rubber. Moreover, stress relaxation was observed at the melting temperature of the modifying agent.

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

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.

Aging of Natural Rubber Vulcanizates in the Presence of Dithiocarbamates

1959 ◽  
Vol 32 (3) ◽  
pp. 739-747 ◽  
Author(s):  
J. R. Dunn ◽  
J. Scanlan
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Protective Action ◽  
Dicumyl Peroxide ◽  
Vulcanized Rubber ◽  
Aging Properties ◽  
Photochemical Aging ◽  
Natural Rubber Vulcanizates

Abstract The thermal and photochemical aging of extracted dicumyl peroxide-, TMTD (sulfurless)- and santocure-vulcanized rubber, in presence of a number of metal and alkylammonium dithiocarbamates, has been investigated by measurements of stress relaxation. The dithiocarbamates have a considerable protective action upon the degradation of peroxide- and TMTD-vulcanizates, but they accelerate stress decay in santocure-accelerated vulcanizates. The reasons for this behavior are discussed. It is suggested that the excellent aging properties of unextracted TMTD vulcanizates are due to the presence of zinc dimethyldithiocarbamate formed during vulcanization.

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