Facilitating high-temperature curing of natural rubber with a conventional accelerated-sulphur system using a synergistic combination of bismaleimides
It is well known that high-temperature curing of natural rubber (NR) with a conventional accelerated-sulfur (CV) system is limited because of reversion. This paper describes the curing behavior and the reversion resistance characteristics of unfilled NR with a CV system in the presence of two differ...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Budapest University of Technology and Economics
2021-01-01
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| Series: | eXPRESS Polymer Letters |
| Subjects: | |
| Online Access: | http://www.expresspolymlett.com/letolt.php?file=EPL-0010772&mi=cd |
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| Summary: | It is well known that high-temperature curing of natural rubber (NR) with a conventional accelerated-sulfur (CV) system is limited because of reversion. This paper describes the curing behavior and the reversion resistance characteristics of unfilled NR with a CV system in the presence of two different bismaleimides: Perkalink 900 (PL) and Maleide F (MF). Rheometer studies reveal that MF can directly interact with the NR during accelerated-sulfur curing and forms some thermally stable bismaleimide type crosslinks in the beginning via Alder-ene reaction. However, even with the use of 4 phr of MF, a considerable reversion was noticed during the curing of NR with CV at 180 °C for 1 hr. A high dosage (5 phr) of MF was therefore required for a complete reversion free plateau type cure pattern. On the other hand, PL has no direct interaction with the NR at the beginning of the curing reaction. Moreover, even 1 phr PL exhibits a marching modulus curing behavior via Diels-Alder reaction. Therefore, to solve the individual issues of these chemicals, a synergistic combination of MF and PL has been identified and applied to facilitate the high-temperature curing of NR/CV devoid of reversion with a plateau type cure pattern. |
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| ISSN: | 1788-618X |