Reversion free high-temperature vulcanization of cis-polybutadiene rubber with the accelerated-sulfur system

• Main Authors: S. Gopi Sathi, R. Stocek, O. Kratina
• Format: Article
• Language: English
• Published: Budapest University of Technology 2020-09-01
• Series: eXPRESS Polymer Letters
• Subjects: rubber; vulcanization; reversion; bismaleimide; diels-alder reaction
• Online Access: http://www.expresspolymlett.com/letolt.php?file=EPL-0010496&mi=cd

The vulcanization of high diene elastomers with conventional or semi-efficient vulcanization systems exhibit reversion at a higher temperature due to the breakage of the polysulfidic crosslinks established in the vulcanized network. As a result, the vulcanizate show inferior mechanical and thermal stability at elevated temperature. In this contest, the anti-reversion ability of Maleide F (75% N,N'-meta phenylene dimaleimide and a 25% blending agent: MF) was evaluated on the vulcanization behavior of cis-polybutadiene rubber (BR) with a conventional accelerated sulfur system. The anti-reversion ability of MF was also compared with Perkalink 900 (1,3-bis (citraconimidomethyl) benzene: PL). Based on the vulcanization studies using a moving die rheometer, it has been realized that MF forms carbon-carbon based bismaleimide crosslinks at the beginning of the vulcanization via Alder-Ene reaction. As a result, MF-filled systems exhibit a remarkable reversion resistance and a plateau type cure behavior even at 180 °C for a period of 1hr. On the other hand, PL shows its anti-reversion activity via Diels-Alder reaction after a short reversion. Moreover, the PL filled system exhibits a marching-modulus cure behavior at a higher vulcanization temperature. Therefore, PL cannot be considered as a promising candidate for the hightemperature vulcanization of BR with accelerated sulfur.