Alkylphenol Disulfide Polymer Accelerators and the Vulcanization of Isobutylene Based Elastomers

Brendan Rodgers; Scott Solis; Nitin Tambe; Bharat B. Sharma

doi:10.5254/1.3548222

Alkylphenol Disulfide Polymer Accelerators and the Vulcanization of Isobutylene Based Elastomers

Rubber Chemistry and Technology ◽

10.5254/1.3548222 ◽

2008 ◽

Vol 81 (4) ◽

pp. 600-624 ◽

Cited By ~ 8

Author(s):

Brendan Rodgers ◽

Scott Solis ◽

Nitin Tambe ◽

Bharat B. Sharma

Keyword(s):

Double Bond ◽

Natural Rubber ◽

Butyl Rubber ◽

Development Work ◽

Cure Rate ◽

Rubber Tire ◽

Carbon Double Bond ◽

Rubber Compounds ◽

Starting Point ◽

Further Development

Abstract Vulcanization of isobutylene/isoprene copolymer (butyl rubber) using sulfur and organic accelerators is facilitated by the presence of the carbon-carbon double bond in the copolymer isoprenyl unit. The low number of unsaturated monomer units, usually in the order of 2%, has traditionally necessitated use of ultra-fast accelerators such as tetramethyl thiuram disulfide (TMTD) or zinc dimethyldithiocarbamate (ZMDC). Use of such accelerators can result in formation of nitrosamines which may be undesirable. There are a number of alternatives to thiuram and dithiocarbamate cure systems such as use of xanthates and phosphate based accelerators. Alkylphenol disulfide based accelerators also enable attainment of favorable properties when used in butyl and halobutyl compounds. Use of alkylphenol disulfide accelerators in butyl rubber compounds can allow improvement in reversion resistance, adhesion to natural rubber tire casing compounds, and aged property retention. In bromobutyl compounds containing alkylphenol disulfide accelerators in binary (two accelerators) or tertiary (three accelerators) cure systems, adjustment in cure rate to meet specific requirements and aged property retention is possible. This, fifth in a series of studies on the vulcanization of isobutylene elastomers, explores the use of alkylphenol disulfide cure systems for vulcanization of both butyl and bromobutyl rubbers and is intended to provide a starting point for further development work.

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Effect of Ingredient Loading on Vulcanization Characteristics of a Natural Rubber Compound

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1125.50 ◽

2015 ◽

Vol 1125 ◽

pp. 50-54 ◽

Cited By ~ 3

Author(s):

Bryan B. Pajarito

Keyword(s):

Natural Rubber ◽

Raw Materials ◽

Fractional Factorial ◽

High Loading ◽

Rubber Compound ◽

Cure Rate ◽

Used Oil ◽

Rubber Compounds ◽

Cure Time ◽

Viscous Torque

Rheometric properties of rubber compounds are usually monitored with time during the course of vulcanization at constant temperature. The measured vulcanization characteristics of rubber compound are used for quality control and evaluation of raw materials and product formulations. With the high number of ingredients used in typical formulations, it is important to identify ingredients which significantly affect the vulcanization characteristics of a rubber compound. This study reports the vulcanization characteristics of a natural rubber compound at 60 °C as function of ingredient loading. Rubber sheets are compounded according to a 212-8 fractional factorial design of experiment, where ingredients are treated as factors varied at low and high loadings. Vulcanization curves, which are time plots of elastic torque S’, viscous torque S”, and tan δ = S”/S’, are measured for each rubber sheet using a moving die rheometer. The following responses are then determined from the vulcanization curves for data analysis: minimum elastic torque ML, maximum elastic torque MH, torque difference ∆S = MH – ML, scorch time ts1, cure time t’90, cure rate index CRI = 100/ (t’90 – ts1), S” and tan δ values at ML and MH. Analysis of variance (ANOVA) shows used oil to be the main ingredient affecting vulcanization of the natural rubber compound (ML, MH, ∆S, ts1, S” at ML and MH), followed by sulfur (MH, ∆S, CRI), calcium carbonate CaCO3 (S” at ML, tan δ at MH) and diphenylguanidine DPG (ts1). High loading of used oil lowers the elastic and viscous response of the rubber compound, while increases the time for scorch. Increased loading of sulfur significantly enhances the elastic torque and cure rate of the compound. High loading of CaCO3 improves the viscous response, while DPG significantly shortens the scorch time of the rubber compound.

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Optimization of Epoxidation Degree and Silane Coupling Agent Content for Silica-Filled Epoxidized Natural Rubber Tire Tread Compounds

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.844.243 ◽

2013 ◽

Vol 844 ◽

pp. 243-246 ◽

Cited By ~ 1

Author(s):

Wisut Kaewsakul ◽

Kannika Sahakaro ◽

Wilma Dierkes ◽

Jacques W.M. Noordermeer

Keyword(s):

Natural Rubber ◽

Coupling Agent ◽

Silane Coupling Agent ◽

Silica Content ◽

Epoxidized Natural Rubber ◽

Rubber Tire ◽

Rubber Compounds ◽

Silane Coupling ◽

Reinforcement Efficiency

Parallel studies on the influence of epoxide contents in epoxidized natural rubbers (ENRs) in the absence of bis-(triethoxysilylpropyl) tetrasulfide (TESPT) coupling agent, as well as a combination of ENRs with different loadings of TESPT on the properties of ENR compounds, are carried out in this work. The results suggests that the best possible combination to optimize processibility and to improve reinforcement efficiency is to utilize ENR with an epoxide content in the range of 20 30 mol%, together with 2 4 wt% relative to the silica content of TESPT. This leads to a reduction of TESPT when compared to the conventional natural rubber compounds.

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Dynamic-Mechanical Characteristics of Rubber Compounds

Rubber Chemistry and Technology ◽

10.5254/1.3542623 ◽

1956 ◽

Vol 29 (4) ◽

pp. 1215-1232 ◽

Cited By ~ 3

Author(s):

S. de Mey ◽

G. J. van Amerongen

Keyword(s):

Carbon Black ◽

Natural Rubber ◽

Loss Factor ◽

Mechanical Characteristics ◽

Strain Curve ◽

Shear Loading ◽

Butyl Rubber ◽

Amplitude Dependence ◽

Dynamic Mechanical ◽

Rubber Compounds

Abstract Since rubber articles are often exposed in service to small periodic deformations, great interest attaches to the dynamic-mechanical characteristics of rubber. It has been established that the conditions under which these characteristics are determined have a pronounced influence on the results obtained, so that the measurements must be undertaken under precisely specified conditions. A new test apparatus is described for measuring the dynamic-mechanical characteristics, with which measurements can be performed at any desired stress setting, frequency, temperature, and amplitude on the same samples, both for compression and for shear loading. The incompressibility of filler-free natural-rubber compounds has been demonstrated by measurements made on samples with different shape factors and with varied static initial stress, under compression and with shear loading. The temperature, frequency, and amplitude dependence of the dynamic-mechanical characteristics of different rubber compounds is discussed on the basis of a number of measurements. The maximum value of the loss factor, which occurs in the vicinity of the second-order transition point, appears at a higher temperature in GR-S (cold rubber), Vulkollan, and Butyl rubber than in natural rubber. There is a connection between this fact and the much greater frequency and temperature dependence of Butyl rubber compared to natural rubber in the vicinity of room temperature. A compound based on natural rubber and a styrene-butadiene (85/15) co-polymer shows two maxima in the loss factor. One of these is characteristic of natural rubber, the other of the polymer. The dynamic characteristics of filler-free rubber compounds are not very sensitive to amplitude. It is found that the marked amplitude dependence of reinforced rubber compounds cannot be accounted for by increased temperature or by any nonlinearity of the stress-strain curve. The influence of composition on the dynamic-mechanical characteristics of natural rubber has been tested for a number of compounds. It is established that the carbon black types can have a significant effect on the E′ modulus. At small amplitudes the magnitude is greater for a compound containing SAF or EPC carbon black than for one containing HAF carbon black. Natural rubber reinforced with Aerosil or aniline resin shows a small loss factor, while compounds vulcanized with Thiuram show a large one. The present study is part of a fundamental investigation on rubber carried out by the Research Division of the Rubber-Stichting in Delft under the direction of H. C. J. de Decker.

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ENHANCING PERFORMANCE OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS BY APPLYING ORGANOCLAY AS SECONDARY FILLER

Rubber Chemistry and Technology ◽

10.5254/rct.20.80373 ◽

2020 ◽

pp. 000-000 ◽

Cited By ~ 1

Author(s):

S. Sattayanurak ◽

K. Sahakaro ◽

W. Kaewsakul ◽

W. K. Dierkes ◽

L. A. E. M. Reuvekamp ◽

...

Keyword(s):

Natural Rubber ◽

Filler Content ◽

Resistance Index ◽

Rolling Resistance ◽

Cure Rate ◽

Hybrid Filler ◽

Payne Effect ◽

Pure Silica ◽

Rubber Tire ◽

Wet Skid Resistance

ABSTRACT Silica-reinforced natural rubber (NR) tire tread compounds are investigated using organoclay (OC) as secondary filler. By varying mixer temperature settings at a silica/OC ratio of 45/10 phr, dump temperatures are reached of approximately 120, 140, 150, and 160 °C. The increased dump temperature leads to a better silanization reaction resulting in lower mixing torque, Mooney viscosity, and Payne effect. The optimum mixing dump temperature was found to be around 150 °C. By varying the loadings of OC in the silica-filled NR compounds from 0 to 36 wt% relative to total filler amount, the increased OC loadings decreased the Payne effect and compound viscosities, significantly shortened scorch and cure times, and raised the tan delta at −20 and 0 °C as indications for ice traction and wet skid resistance of tire treads made therefrom. The optimum loading of OC of 18 wt% relative to total filler content shows better Payne effect, cure rate index, tan delta at −20 and 60 °C indicative for rolling resistance, and DIN abrasion resistance index. The results indicate that the use of this hybrid filler may provide tires with better wet traction and lower rolling resistance and wear resistance compared with the pure silica-filled system.

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