The Heat Aging of Natural Rubber Vulcanized with Tetramethylthiuram Disulfide

1958 ◽  
Vol 31 (2) ◽  
pp. 327-328 ◽  
Author(s):  
W. P. Fletcher ◽  
S. G. Fogg
Keyword(s):  
Natural Rubber ◽  
Heat Resistance ◽  
Major Part ◽  
Aging Behavior ◽  
Tetramethylthiuram Disulfide ◽  
Acetone Extraction ◽  
Aging Resistance

Abstract Acetone extraction of the TMTD stock, which is known to remove the ZnDMDC formed during vulcanization, also leads to a reduction in heat aging resistance. Addition to the extracted vulcanizate of the appropriate quantity of ZnDMDC from a solution improves the aging behavior although not to the level of the untreated vulcanizate. This failure to restore in full the aging resistance of the initial stock by swelling in the appropriate quantity of ZnDMDC is hardly surprising since it is likely that the ZnDMDC will be present in the original and in the dosed vulcanizate in somewhat different physical forms and distributions. The results demonstrate that the dithiocarbamate formed in situ during TMTD vulcanization plays a major part in conferring heat resistance to such vulcanizates.

Aging of GR-S Vulcanizates. IV. Influence of the Vulcanizing Ingredients, Antioxidant, and Softener

1950 ◽  
Vol 23 (2) ◽  
pp. 397-403 ◽  
Author(s):  
J. R. Scott
Keyword(s):  
Tensile Strength ◽  
Aging Behavior ◽  
Tetramethylthiuram Disulfide ◽  
Oxygen Bomb ◽  
Acetone Extraction ◽  
Low Sulfur ◽  
Tension Strength

Abstract The results of air aging at temperatures from 25° to 100° C and of oxygen-bomb aging are discussed in relation to the composition of the mix; notes are given also on the relation of composition to the properties before aging. The main conclusions are: (1) a low proportion of sulfur or (still better) vulcanization by tetramethylthiuram disulfide (TMT) improves the maintenance of tensile strength and elongation under all conditions examined; a low-sulfur mix containing selenium gives results intermediate between the normal low-sulfur and TMT-vulcanized mixes; (2) when judged by the stiffening and hardening during aging, the relative merits of these alternative vulcanizing agents are different, age-stiffening being generally least with low sulfur plus selenium and greatest with TMT vulcanization; (3) on the whole, mercapto-benzothiazole (MBT) gave better results than TMT as an accelerator in mixes with the same proportion of sulfur; (4) acetone extraction of raw GR-S did not lead to the bad aging expected from the removal of antioxidant, but this point needs further study in view of contrary conclusions by other workers; (5) a large proportion of softener somewhat improves maintenance of strength but increases age-stiffening; (6) in general the formulation giving the best maintenance of tension strength and elongation does not give the least age-stiffening, and vice-versa; for the former, TMT vulcanization (possibly plus softener) appears best; for the latter an MBT-accelerated low-sulfur mix, possibly plus selenium, and (7) the 100° C air and the oxygen-bomb aging tests may give misleading indications of aging behavior in air at lower temperatures.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

Reinforcing efficiency and compatibilizing effect of sol–gel derived in situ silica for natural rubber/chloroprene rubber blends

RSC Advances ◽  
2014 ◽  
Vol 4 (102) ◽  
pp. 58816-58825 ◽  
Author(s):  
Bharat P. Kapgate ◽  
Chayan Das
Keyword(s):  
Natural Rubber ◽  
Sol Gel ◽  
Rubber Blends ◽  
In Situ Silica ◽  
Chloroprene Rubber ◽  
Compatibilizing Effect

The strong CR/in situ silica interaction causes filler accumulation at the interphase and enhances the compatibility and reinforcement in the NR/CR blend.

scholarly journals Study on the Aging Behavior of Natural Rubber/Butadiene Rubber (NR/BR) Blends Using a Parallel Spring Model

Polymers ◽  
2018 ◽  
Vol 10 (6) ◽  
pp. 658 ◽  
Author(s):  
Byungwoo Moon ◽  
Jongmin Lee ◽  
Soo Park ◽  
Chang-Sung Seok
Keyword(s):  
Natural Rubber ◽  
Butadiene Rubber ◽  
Spring Model ◽  
Aging Behavior

scholarly journals Microstructure and Properties of SCE-Al2O3/PES-MBAE Composite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yufei Chen ◽  
Qiwang Dai ◽  
Xiwang Zhang ◽  
Tao Feng
Keyword(s):  
Dielectric Properties ◽  
Bisphenol A ◽  
Heat Resistance ◽  
Bending Strength ◽  
Sol Gel ◽  
Harmful Effect ◽  
Decomposition Temperature ◽  
Two Phase ◽  
Allyl Compound

SCE-Al2O3was the nano-Al2O3modified by supercritical ethanol and the surface of SCE-Al2O3was coated with active group. 4,4′-diaminodiphenylmethane bismaleimide (MBMI) was used as matrix; 3,3′-diallyl bisphenol A (BBA) and bisphenol-A diallyl ether (BBE) were used as reactive diluent, polyethersulfone (PES) as toughening agent, and SCE-Al2O3as modifier; SCE-Al2O3/PES-MBAE nanocomposite was prepared through in situ sol-gel method. The mechanism of composite toughened by PES was observed and analyzed. FTIR indicated that the reaction between MBMI and allyl compound occurred and SCE-Al2O3had doped into the polymer matrix. SEM showed that PES particle was inlaid in matrix and presented as a two-phase structure in matrix. The heat resistance, dielectric properties, and mechanical properties of SCE-Al2O3/PES-MBAE nanocomposites were evaluated. The results showed that with the incorporation of PES, although the toughness of the material improved, the heat resistance and dielectric properties of material declined, meanwhile. The adulteration of SCE-Al2O3could remedy the harmful effect caused by PES, while the content of SCE-Al2O3was reasonable. The decomposition temperature, dielectric constant, and dielectric loss of composite were 441.23°C, 3.63 (100 Hz), and 1.52 × 10−3(100 Hz); the bending strength and impact strength were 129.22 MPa and 13.19 kJ/mm2, respectively, when the content of SCE-Al2O3was 3 wt% and PES was 5 wt%.

Reinforcement of Natural Rubber: The Use of in Situ Regenerated Cellulose from Alkaline–Urea–Aqueous System

2017 ◽  
Vol 50 (18) ◽  
pp. 7211-7221 ◽  
Author(s):  
Peng Yu ◽  
Hui He ◽  
Yuanfang Luo ◽  
Demin Jia ◽  
Alain Dufresne
Keyword(s):  
Natural Rubber ◽  
Aqueous System ◽  
Regenerated Cellulose
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