Physical, mechanical, and viscoelastic properties of natural rubber vulcanizates cured with new binary accelerator system

2003 ◽  
Vol 87 (14) ◽  
pp. 2193-2203 ◽  
Author(s):  
Abi Santhosh Aprem ◽  
Kuruvilla Joseph ◽  
R. Laxminarayanan ◽  
Sabu Thomas
Keyword(s):  
Natural Rubber ◽  
Viscoelastic Properties ◽  
Natural Rubber Vulcanizates ◽  
Accelerator System

Kinetics of Crosslinking and Network Changes in Natural Rubber Vulcanizates with a Dithiodimorpholine Based Accelerator System

1980 ◽  
Vol 53 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
A. K. Bhowmick ◽  
S. K. De
Keyword(s):  
Natural Rubber ◽  
Rate Constants ◽  
Crosslink Density ◽  
Curing Temperature ◽  
Side Reactions ◽  
Filler Surface ◽  
Natural Rubber Vulcanizates ◽  
Kinetics Of ◽  
Accelerator System

Abstract Kinetics of crosslinking and network changes in unfilled and filled natural rubber vulcanizates with a dithiodimorpholine based accelerator system have been studied at 150° and 180°C. Results show that addition of HAF black enhances the polysulfidic crosslinks as well as the total crosslinks. This has been explained with the help of Coran's model wherein HAK black increases the rate constants. It is likely that the filler surface prevents desulfuration and undesirable side reactions involving the crosslink precursors. Increase of curing temperature by 30°C lowers the total crosslink density and increases the sulfur inefficiency.

HXNBR Coating for Improving Aging Resistance of Natural Rubber Products

2006 ◽  
Vol 79 (4) ◽  
pp. 553-560 ◽  
Author(s):  
Rani Joseph
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Room Temperature ◽  
Oxidative Degradation ◽  
Thin Coating ◽  
Oil Resistance ◽  
Aging Resistance ◽  
Natural Rubber Vulcanizates ◽  
Good Heat ◽  
Accelerator System

Abstract HXNBR (Hydrogenated Carboxylated Nitrile Rubber) has very good heat ageing resistance and oil resistance. A novel accelerator system is designed to bring about the vulcanization of HXNBR at room temperature. The room temperature cured samples showed good mechanical properties equivalent to those of high (150 °C) temperature cured samples. Natural rubber vulcanizates are highly prone to oxidative and ozone degradation. The oil resistance of natural rubber vulcanizates is also very low. The oil resistance, ozone and oxidative degradation resistance of natural rubber vulcanizates are considerably improved by placing a thin coating of HXNBR over it.

Effect of Filler Networking on Viscoelastic Properties and Reinforcement of Natural Rubber Vulcanizates

2010 ◽  
Vol 49 (3) ◽  
pp. 429-439 ◽  
Author(s):  
Jingjie Han ◽  
Ning Shi ◽  
Linsheng Xie ◽  
Yulu Ma ◽  
Chifei Wu
Keyword(s):  
Natural Rubber ◽  
Viscoelastic Properties ◽  
Natural Rubber Vulcanizates

Mechanical and Swelling Behavior of Double Networked Natural Rubber Cured Using a New Binary Accelerator System

2007 ◽  
Vol 80 (5) ◽  
pp. 809-819 ◽  
Author(s):  
C. V. Marykutty ◽  
G. Mathew ◽  
Sabu Thomas
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Transverse Direction ◽  
Tensile Elongation ◽  
Longitudinal Direction ◽  
Chain Orientation ◽  
Swelling Studies ◽  
Natural Rubber Vulcanizates ◽  
Double Networks ◽  
Accelerator System

Abstract The concept of double networks, which impart chain orientation to elastomers, is a rather new idea. Double networks were induced in natural rubber vulcanizates cured with different accelerator systems. Double networked natural rubber with different extensions cured with N-cyclohexyl benzothiazyl sulphenamide (CBS) and 1-phenyl 5-ortho -tolyl 2,4 dithiobiuret was studied and the effect of extension on the mechanical properties and swelling was analyzed. The extent of chain orientation was analyzed through anisotropic swelling studies. The modulus, tensile strength and tear strength showed an increase with increased residual extension ratio. The effect was more predominant in the longitudinal direction than in the transverse direction. The ultimate tensile elongation showed a slight deterioration. It was revealed that the formation of double networks with higher residual extension ratios restricted the entry of the solvent. Based on the studies it was concluded that residual extension has a profound effect in determining the final properties of vulcanizates.

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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