Abstract
In this work, studies are carried out to understand the crosslinking reaction of epoxidized natural rubber (50 mol% epoxy, ENR-50) by metal ion namely ferric ion (Fe3+, FeCl3, ferric chloride). It is found that a small amount of FeCl3 can cure ENR to a considerable extent. A direct interaction of the ferric ion with the epoxy group as well as internal polymerization enable the ENR to be cured in an efficient manner. It was also found that with the increased concentration of FeCl3, the crosslinking density of the matrix increased and therefore, the ENR offers higher mechanical properties (i.e., modulus and tensile strength). In addition, the glass transition temperature (tg) of ENR vulcanizate is increased with increasing concentration of FeCl3. Moreover, the thermal degradation temperature (Td) of the ENR-FeCl3 compound was shifted toward higher temperature as increasing concentration FeCl3.
Highlights
Vulcanization of rubber is a process to form permanent rubber network structures with useful properties
It is clearly seen that the neat epoxidized natural rubber (ENR)-50 and unmodified Natural rubber (NR) (ADS) with 7 mmol FeCl3 had no response of mixing torque-time relation, indicating no establishment of network structure
The curing curves of ENR- FeCl3 compounds have not reached to the equilibrium curing state within the experimental time of 1 h
Summary
Vulcanization of rubber is a process to form permanent rubber network structures with useful properties. The sulfur cured vulcanizates generally exhibit good mechanical and other technical properties, but the chemistry behind of such crosslinking is rather complex. Incorporation of metal ions in epoxidized natural rubber (ENR) can lead to crosslinking reaction, and it is supposed that the network formation may be associated with coordination crosslinks (such as, Fe3+–O bond) [9]. It was found that the metal–ligand bonds are formed through the coordination reaction between the pyridine groups in butadiene–styrene–vinylpyridine rubber (VPR) and metal ions. This contributes to increase the stiffness of the material at small strain and rupture and with increasing strain, a complete recovery was achieved after stretching [14]. Studies like stress-relaxation and dielectric relaxation spectra are done to enlighten the network structure provided by ferric chloride
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
