The effect of accelerator/sulphur ratio on the scorch time of epoxidized natural rubber

Sadequl, A. M.; Ishiaku, U. S.; Ismail, Hanafi; Poh, B. T.

doi:10.1016/s0014-3057(97)00067-0

Cited by 58 publications

(31 citation statements)

References 13 publications

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“…Five accelerators MBT, TMTD, ZDMC, DPG and TBBS were supplied by Bayer. The technical specifications of the rubbers and accelerators were given in our previous paper [3]. Carbon black (330), silica (vulkasil-S) and calcium carbonate having a surface area of 70 m2/g, 170 m2/g and 22 m2/g and partical size of 30 nm, 19 nm and 75 nm respectively were chosen as the fillers, with loading ranged from 0 -60 phr.…”

Section: Methodsmentioning

confidence: 99%

“…The concentrations of sulphur and the accelerators were varied to ascertain different vulcanization systems i.e. CV, semi-EV and EV [3]. The compound was then kept in a close container maintained at 23 i 3°C for 24 h before testing.…”

Section: Methodsmentioning

confidence: 99%

“…It was also found that the influence of accelerator/sulphur ratio becomes less significant as vulcanization temperature increases. [3] showed that ENR 25 shows shorter scorch time compared with natural rubber (NR). This has been attributed to the activation of the double bond by the oxirane group.…”

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confidence: 99%

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The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Sadequl

2000

International Journal of Polymeric Materials and Polymeric Biom

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The cure time of accelerated sulphur vulcanization of Epoxidized Natural Rubber (ENR 25) was studied while one grade of unmodified natural rubber -Standard Malaysian Rubber Light (SMR L) was used as a control. Five accelerators, viz. 2-mercaptobenzothiazole (MBT), tetramethylthiuram disulphide (TMTD), zinc dirnethyldithiocarbamate (ZDMC), N-tert-butyl-2-benzothiazylsulphenamide (TBBS) and diphenylguanidine (DPG) were used in the study and the vulcanization systems used were conventional vulcanization (CV), semi-efficient vulcanization (semi-EV) and efficient vulcanization (EV). Monsanto Moving-Die Rheometer (MDR 2000) was used to determined the cure time in the temperature range of 100-180°C. The results indicate that cure time decreases exponentially with increasing temperature for the two rubbers studied. At a fixed curing temperature, ENR 25 shows shorter cure time compared to that of SMR L. This has been attributed to the activation of the double bond by the adjacent epoxide group in ENR 25. Studies of the effect of varying amounts of M BT at a fixed sulphur concentration show that cure time decreases as the accelerator concentration increases. ENR 25 shows higher torque maximum than SMR L. This observation can be related to the oxiranegroup which is bulky and thus accounts for increased glass transition temperature with increase in the level of epoxidation. Of the vulcanization systems, CV shows the highest torque maximum followed by semi-EV and than EV. This trend can be attributed to the amount of active sulphurating agent which increases with increasing accelerator concentration. It was also found that the influence of accelerator/sulphur ratio becomes less significant as vulcanization temperature increases.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Sadequl

2000

International Journal of Polymeric Materials and Polymeric Biom

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“…This phenomenon is caused by the activation effect of the polar epoxidized groups on double bonds, which also made unfilled ETPI 18 mix have shorter vulcanizate time (t 90 ) [14,15]. With the increase of C 1 , the epoxy groups on ETPI molecular were well distributed, thus making adjacent double bonds more activate and subsequent the unfilled ETPI 18 mix with higher C 1 showed faster curing rate in curing reaction.…”

Section: Resultsmentioning

confidence: 99%

Composition-properties relationship in epoxidized trans-1,4-polyisoprene obtained by heterogeneous method

Yao

Shao

et al. 2015

Polym. Sci. Ser. A

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In this study, the correlations between composition and properties of epoxidized trans 1,4 poly isoprene (ETPI) with the same epoxy degree have been established. It can be seen from the morphology obtained by SEM, there was a clear distinction of phase separation between the raw ETPI samples with dif ferent compositions. Also, the mechanical properties of raw ETPI and curing characters of unfilled ETPI mix were analyzed. All these results showed regular changes which was correlated with ETPI compositions. DMA studies demonstrated that ETPI with higher epoxy content possessed good wet skid resistance and low rolling resistance which could be used as tire tread for high performance tires. While, ETPI with lower epoxy content showed great potential as damping materials due to its broad damping temperature.

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“…In the past, these molecular species have been used as polymer catalysts, [5] fungicides, [6] bactericides, [7,8] or molecular markers for urban environment [9] and present a good molecular stability in solution at room temperature and under visible light. However, after preparing an aqueous solution of indoline-2-thione and exposing this solution to solar radiation, we have found that this compound follows a typical behavior of photochemical actinometer of ultraviolet radiation; that is, these compounds present a simple isosbestic spectral pattern after ultraviolet irradiation or sunlight exposition.…”

Section: Introductionmentioning

confidence: 99%

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

Araya

Vargas

Morales

2005

Spectroscopy Letters

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Indoline-2-thione (BC), benzimidazole-2-thione (BN), benzoxazole-2-thione (BO), and benzothiazole-2-thione (BS) define an interesting series of aromatic compounds containing a NCS synthonic unit in a heterocyclic ring of five centers, substituted by atomic centers of the type C, N, O, or S, where the main electronic absorption bands are localized in the spectral range of ultraviolet A or B.The first two singlet electronic transitions of this series, 1 S 0 ! 1 S 1 (n,p Ã ) and 1 S 0 ! 1 S 2 (p,p Ã ), determine the main spectroscopic characteristic of these compounds in order to be used as potential photochemical actinometers of solar ultraviolet radiation. Furthermore, the second electronic transition, localized in the 270-360 nm ultraviolet spectral range, presents a hipsochromic spectral shift as function of the electronic nature of the heteroatomic centers in the heterocyclic ring. In order to determine a spectroscopic assignment of the main absorption bands in aqueous solution and analyze the effect of the substituent on the electronic charge distributions in the ground and the first two singlet excited electronic states, we have used a semiempirical molecular orbital calculation in the INDO/S-CIS approach. On the other hand, we have carried out a molecular orbital calculation in the AM1 framework, in order to determine the energetic stability of the thiones with respect to the thiol compounds.

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The effect of accelerator/sulphur ratio on the scorch time of epoxidized natural rubber

Cited by 58 publications

References 13 publications

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Composition-properties relationship in epoxidized trans-1,4-polyisoprene obtained by heterogeneous method

¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

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The effect of accelerator/sulphur ratio on the scorch time of epoxidized natural rubber

Cited by 58 publications

References 13 publications

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Composition-properties relationship in epoxidized trans-1,4-polyisoprene obtained by heterogeneous method

1π→1π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles

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¹π→¹π* Ultraviolet Absorption Bands and Electronic Charge Transfers in Singlet Excited States of Sulfur Aromatic Heterocycles