Vulcanization of natural rubber by dicumyl peroxide in the presence of sulphur

1973 ◽  
Vol 38 (2) ◽  
pp. 408-416 ◽  
Author(s):  
B. Bakule ◽  
J. Honskus ◽  
J. Nedbal ◽  
P. Zinburg
Keyword(s):  
Natural Rubber ◽  
Dicumyl Peroxide

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.

scholarly journals Grafting copolymer cylic natural rubber with oleic acid using dicumyl peroxide as initiator

2020 ◽  
Author(s):  
Barita Aritonang ◽  
Tamrin ◽  
Basuki Wirjosentono ◽  
Eddiyanto
Keyword(s):  
Oleic Acid ◽  
Natural Rubber ◽  
Dicumyl Peroxide ◽  
Grafting Copolymer

The Dependence of Dielectric Properties on Crosslink Density of Rubbers

1978 ◽  
Vol 51 (1) ◽  
pp. 72-80 ◽  
Author(s):  
R. Bakule ◽  
A. Havránek
Keyword(s):  
Dielectric Properties ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Unit Volume ◽  
Volume Distribution ◽  
Dicumyl Peroxide ◽  
Frequency Range ◽  
Polar Groups ◽  
Main Transition ◽  
Macroscopic Parameters

Abstract The dielectric properties of natural rubber, synthetic polyisoprene, andpolybutadiene samples crosslinked with sulfur and of natural rubber samplescrosslinked simultaneously with sulfur and dicumyl peroxide were studied. Inthe investigated systems, the number of polar groups in unit volume and thecrosslink density may be changed independently over relatively wide ranges.The measurements were performed in the frequency range from 101 to 105 Hzat various temperatures, and macroscopic parameters describing the dielectricproperties of the samples were evaluated. The position and intensity of thedielectric dispersion peak in the main transition zone is only slightly dependenton the crosslink density of the samples. These two values are mainly influencedby the amount of combined sulfur, or more generally, by the number and thedipole moments of polar groups in the sample. The influence of crosslink densityon the width of the absorption curve is very strong; the width increases withincreasing crosslink density. The possibility of explaining this effect in termsof the dependence of the free volume distribution function on crosslink densityis discussed.

scholarly journals Modulus of Natural Rubber Crosslinked by Dicumyl Peroxide. I. Experimental Observations

1972 ◽  
Vol 45 (5) ◽  
pp. 1388-1402 ◽  
Author(s):  
L. A. Wood ◽  
G. W. Bullman ◽  
G. E. Decker
Keyword(s):  
Glass Transition ◽  
Natural Rubber ◽  
General Relation ◽  
Quantitative Measure ◽  
Cross Linking ◽  
Rigid Sphere ◽  
Dicumyl Peroxide ◽  
Shear Creep ◽  
Rubber Sheet ◽  
Creep Modulus

Abstract Natural rubber mixed with varying amounts of dicumyl peroxide are crosslinked by heating 120 min at 149° C. The quantitative measure of cross- linking was taken as the amount fp of decomposed dicumyl peroxide, the product of p, the number of parts added per hundred of rubber and f the fraction decomposed during the time of cure. The shear creep modulus G was calculated from measurements of the indentation of a flat rubber sheet by a rigid sphere. The glass transition temperature Tg, was raised about 1.2° C for each part of decomposed dicumyl peroxide. Above (Tg+12) the modulustemperature relations were linear with a slope that increased with increasing crosslinking. The creep rate was negligible except near the glass transition and at low values of fp. Values of G, read from these plots at seven temperatures, were plotted as a function of fp. The linearity of the two plots permits the derivation of the general relation: G=S(fp+B)T+H(fp+B)+A where A, B, H, and S are constants. The lines representing G as a function of fp at each temperature all intersected near the point, fp=0.45 phr, G=2.70 Mdyn cm−2(0.270 MN  m−2). . The constants were evaluated as A=2.70 Mdyn cm−2,B=−0.45 phr, S=5.925×10−3 Mdyn cm−2(phr)−1 K−1 and H=0.0684(Mdyn cm−2) (phr)−1. This equation represented satisfactorily all the data obtained at temperatures from —50 to +100° C for values of fp from about 1 to 24 phr.

Effect of Sulfur and Dicumyl Peroxide on Vulcanization of Natural Rubber with Tetramethylthiuram Disulfide and Zinc Oxide

1970 ◽  
Vol 43 (6) ◽  
pp. 1294-1310 ◽  
Author(s):  
S. P. Manik ◽  
S. Banerjee
Keyword(s):  
Zinc Oxide ◽  
Stearic Acid ◽  
Natural Rubber ◽  
Reaction Mechanisms ◽  
Elemental Sulfur ◽  
Initial Rate ◽  
Dicumyl Peroxide ◽  
Tetramethylthiuram Disulfide ◽  
Sulfur Vulcanization ◽  
Salient Features

Abstract The salient features of both non-elemental sulfur vulcanization by TMTD and elemental sulfur vulcanization promoted by TMTD both in presence and absence of ZnO and stearic acid have been studied. TMTD increases the rate of DCP decomposition and lowers the crosslinking maxima due to DCP depending on its concentration. However, with higher amounts of TMTD the initial rate of crosslinking is increased with the increased amount of TMTD, while crosslinking maxima are still lowered due to reversion. ZnO or ZnO-stearic acid, however, seems to alter the entire course of the reaction. Both the crosslink formation and TMTD decomposition are much higher in presence of ZnO or ZnO-stearic acid, but stearic acid seems to have no effect. The reaction mechanisms for TMTD accelerated sulfuration in absence and presence of ZnO have also been studied.

Relative Contributions of Viscoelasticity and Aging to the Relaxation of Rubber Vulcanizates

1963 ◽  
Vol 36 (1) ◽  
pp. 50-58 ◽  
Author(s):  
P. Thirion ◽  
R. Chasset
Keyword(s):  
Quantitative Analysis ◽  
Natural Rubber ◽  
Time Interval ◽  
Dicumyl Peroxide ◽  
Infinite Time ◽  
Negative Power ◽  
Theoretical Assumptions ◽  
The Difference ◽  
Natural Rubber Vulcanizates ◽  
Actual Stress

Abstract Relaxation in relatively stable, gum natural rubber vulcanizates has been studied to determine the effects of viscoelasticity and aging, respectively, using a dark, air-oven. A quantitative analysis of experimental results shows that, in the case of a dicumyl peroxide vulcanizate at 100° C, relaxation is caused by aging, except in its initial stages. Stress decreases as a linear function of time, in agreement with theoretical assumptions. Conversely, at 30° C, the effect of aging is negligible. At this temperature the difference between actual stress and stress extrapolated to infinite time, is proportional to a negative power of time. At intermediate temperatures, both phenomena occur simultaneously over a time interval ranging from. 3 minutes to 150 hours.

scholarly journals Grafting of Oleic Acid On Cyclic Natural Rubber Resiprene-35 Using Dicumyl Peroxide Initiator and Divinylbenzene Compatibilizers For Paint Binder In Polyamide Thermoplastics

2019 ◽  
Vol 35 (1) ◽  
pp. 173-179
Author(s):  
Barita Aritonang ◽  
Tamrin Tamrin ◽  
Basuki Wirjosentono ◽  
Eddiyanto Eddiyanto
Keyword(s):  
Oleic Acid ◽  
Natural Rubber ◽  
Dicumyl Peroxide ◽  
Weak Peak

In this paper, we reported about modifications of Cyclic Natural Rubber (CNR) with Oleic Acid (OA) and divinylbenzene (DVB) and dicumyl peroxide (DCP). The aim of this research isto improve their compatibility as a paint binder in polyamide thermoplastic substrates. The method of this research is grafting method in order to know grafting process of CNR to generate CNR-g-OA, and its compatibility after being blended with Polyamide (PA). Analysis of CNR-g-OA was carried out by using FTIR and SEM. The results showed that the best compositions ratio of CNR-g-OA are CNR (100 phr), OA (6 phr), DCP (0.5 phr); and DVB (0.5 phr). The FTIR data of CNR-g-OA show that there is a sharp and weak peak at 1700 to 1800 cm-1, indicating that is carbonyl (C=O). It is oleic acid. The SEM data of CNR-g-OA is totally difference compare to CNR-g-OA with polyamide after the addition of DVB. It is caused the grafting was succeed to generate CNR-g-AO and compatible with PA.

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