The Effect of Sulfur Ratio To MBTS Accelerator on Viscoelastic, Vibration Damping, and Thermal Stability Properties of Unfilled Natural Rubber Vulcanizates
Adi Cifriadi(a,b), Purwantiningsih Sugita(a*), Tetty Kemala(a), Siti Nikmatin(c)

(a)Department of Chemistry, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia
(b)Indonesian Rubber Research Institute, Palembang, Indonesia
(c)Department of Physic, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia

Abstract

It is well-recognized that the sulfur ratio to accelerator has greatly influenced the properties of rubber vulcanizates. Viscoelasticity, vibration damping, and thermal stability are important properties of rubber vulcanizates as isolators for automotive applications. The isolator standard are indicated high values of damping factor, viscous modulus, thermal stability, and low values of elastic modulus. This research aims to study the effect of the ratio between sulfur to 2-2^-dithiobenzothiazole (MBTS) accelerator on viscoelastic, vibration damping, and thermal stability properties of unfilled natural rubber (NR) vulcanizates. This ratio was specified respectively at 0.11- 0.22- 1.11- 2.15 and correlates with the efficient, semi-efficient, or conventional types of sulfur vulcanization of rubber vulcanizate. Study of the viscoelastic and vibration damping properties were determined by rubber process analyser (RPA) at frequency variation from 0.08 - 50 Hz at a temperature of 90oC with a fixed strain of 0.5o, and the thermal stability was investigated by thermogravimetric analysis (TGA). The results showed that the semi-efficient type of sulfur vulcanization of unfilled NR vulcanizates containing sulfur ratio to MBTS accelerator at 1.11 had the best of viscoelastic (elastic and viscous modulus) and vibration damping properties (tangent delta) as a rubber isolator. However, in terms of thermal stability properties, the conventional sulfur vulcanization of unfilled NR vulcanizates containing sulfur ratio to MBTS accelerator at 2.15 was the excellent among others. Base on the isolator standard, the semi-efficient type of the sulfur vulcanization of unfilled NR vulcanizates containing sulfur ratio to MBTS accelerator at 1.11 was preferably, but its thermal stability properties need to be increased.

Keywords: rubber, sulfur, viscoelastic, vibration damping, thermal stability

Topic: Polymer Chemistry & Bio-based Materials