Comparative study on mechanical, thermal, viscoelastic and rheological properties of vulcanised EPDM rubber

Çavdar, Şeyma; Özdemir, Tonguç; Usanmaz, Ali

doi:10.1179/174328910x12647080902970

Cited by 24 publications

(25 citation statements)

References 10 publications

(10 reference statements)

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“…As pointed out by Gent [7], the tear strength initially increases as the crosslink level increases, but, after reaching a maximum value, it decreases at excessively high crosslink levels, which restrict chain motions so that the tight network is incapable of dissipating much energy, resulting in relatively easy, brittle fracture at low elongation. This is consistent with the results of [21], which showed that increasing the level of vulcanisation agent and thereby crosslink density initially enhances the mechanical properties, but beyond a certain level further increases have the opposite effect. Alternatively, as compared with the use of MD, it can be inferred that the use of MZ and MZD provide lower crosslink levels that favour tear strength.…”

Section: Combinationssupporting

confidence: 82%

Effects of accelerators on the cure characteristics and mechanical properties of natural rubber compounds

Ahsan¹,

Mohamad²,

Soh³

2015

Int. J. Automot. Mech. Eng.

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The effects of different accelerators on the cure characteristics and mechanical properties of sulphur-cured natural rubber (NR)-based compounds are investigated. Three accelerator systems, with mercaptobenzothiazole disulphide (MBTS) as primary accelerator and diphenylguanidine (DPG) and Zn-2-mercaptobenzothiazole (ZMBT) as secondary accelerators, were incorporated into a premixed NR compound referred to an industrially used rubber mat formulation by using the melt mixing method. The cure characteristics, rubber crosslink density and mechanical properties were the focus in the present study. It is observed that the synergistic effect of the MBTS/DPG combination imparts the shortest scorch time, highest cure rate and highest crosslink density compared with the MBTS/ZMBT and MBTS/ZMBT/DPG combinations. Mechanical tests indicate that the tensile strength and modulus of MBTS/DPG are enhanced owing to improved cure activation in initiating sulphuric crosslinking, but the tear strength is decreased compared with the others. This study demonstrates that the MBTS/ZMBT/DPG system is the most effective in enhancing tear strength by 4.5 % compared with MBTS/DPG system, as well as other mechanical properties. Analyses on tear behaviours and scanning electron microscope (SEM) micrographs of the fractured surfaces of tear test samples correspond well with the results of tear strength.

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Section: Combinationssupporting

confidence: 82%

Effects of accelerators on the cure characteristics and mechanical properties of natural rubber compounds

Ahsan¹,

Mohamad²,

Soh³

2015

Int. J. Automot. Mech. Eng.

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“…The results indicated that PPSQ affects volatile products of EPDM and is detected in its formulation by TG/FT-IR. Çavdar et al [7] studied different vulcanizing agent contents by TG/FT-IR. They observed that increasing vulcanizing agent content decreased band intensities of CO and CO 2 and enhanced the thermal stability of EPDM rubber.…”

Section: Introductionmentioning

confidence: 99%

TG/FT-IR characterization of additives typically employed in EPDM formulations

2015

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SbstractThermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TG/FT-IR) is a very popular technique for rubbers characterization. It involves analyses of the base polymer and additives. Ethylene-propylene-diene (EPDM) rubbers are frequently investigated by TG/FT-IR; however, the focus has been the degradation temperature range of the polymer. In this study, unvulcanized and vulcanized EPDM rubber and its additives were investigated by TG/FT-IR, without solvent extraction, and in a wide temperature range. Initially, the additives were individually characterized. TG/FT-IR identified the characteristic groups of all the additives analyzed and distinguished them from each other. Afterwards, unvulcanized and vulcanized EPDM rubbers were investigated without prior extraction. TG/FT-IR detected absorptions due to the additives tetramethylthiuram monosulfide and 2-mercaptobenzothiazole. Both of these sulfur-containing additives were present in the EPDM formulation at concentrations of 0.7 phr (0.63 wt %). The TG/FT-IR technique had some limitations, because not all the additives in EPDM rubber were detected. Paraffin oil, stearic acid and 2,2,4-trimethyl-1,2-dihydroquinoline functional groups were not observed in either the unvulcanized or vulcanized EPDM. Nevertheless, in addition to the ability of this method to detect sulfur-containing groups, the lack of a pre-extraction reduces the time and effort required for additive analysis in rubbers.

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“…Low molecular weight chemical compounds, known as additives, are incorporated in to rubbers to obtain desirable properties [2] . The main additives used in rubbers are antioxidants, vulcanizing agents, accelerators, reinforcing agents, activators, and processing aids.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Additives Typically Employed in EPDM Formulations by using FT-IR of Gaseous Pyrolyzates

Sanches¹,

Cassu²,

Diniz³

et al. 2014

Polímeros

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Abstract:In this study, Fourier transform infrared spectroscopy (FT-IR) was employed to investigate the gaseous pyrolysis products of ethylene-propylene-diene rubber (EPDM). The objective was to evaluate the potential of FT-IR analysis of gaseous pyrolyzates (PY-G/FT-IR) for characterization of EPDM additives. Two EPDM formulations, containing additives typically employed in EPDM rubbers, were analyzed. Initially, gaseous pyrolysis products from paraffin oil, stearic acid, 2,2,4-trimethyl-1,2-dihydroquinoline, tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), and 2-mercaptobenzothiazole (MBT) were characterized separately, and their main absorptions were identified. Subsequently, the gaseous pyrolysis products of raw, unvulcanized, and vulcanized EPDM formulations were analyzed. The similarities observed in the FT-IR spectra of unvulcanized and vulcanized EPDM show that the vulcanization process does not interfere with the pyrolysis products. The identification of the functional groups of the studied additives was possible in both unvulcanized and vulcanized EPDM samples, without solvent extraction. Results also demonstrate that the PY-G/FT-IR technique can identify additives containing sulfur in concentrations as low as 1.4 phr (1.26%) in both unvulcanized and vulcanized EPDM. However, the method showed some limitation due to overlapping and to similarities of TMTM and TMTD PY-G/FT-IR spectra, which could not be distinguished from each other. The PY-G/FT-IR technique is a faster and cheaper alternative to the sophisticated techniques usually applied to detection of additives in rubbers.

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Comparative study on mechanical, thermal, viscoelastic and rheological properties of vulcanised EPDM rubber

Cited by 24 publications

References 10 publications

Effects of accelerators on the cure characteristics and mechanical properties of natural rubber compounds

Effects of accelerators on the cure characteristics and mechanical properties of natural rubber compounds

TG/FT-IR characterization of additives typically employed in EPDM formulations

Characterization of Additives Typically Employed in EPDM Formulations by using FT-IR of Gaseous Pyrolyzates

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