Continuous Devulcanization by Shear Flow Stage Reaction Control Technology for Rubber Recycling. Part 8. Devulcanization Condition for Peroxide-Crosslinked EPDM and Mechanical Properties of Sulfur-Crosslinked Reclaimed Rubber.

Continuous devulcanization by the shear flow stage reaction control technology for vulcanized rubbers has been developed. This technology has been applied to sulfur-crosslinked rubbers such as EPDM, NR/SBR (used tire waste) and IIR (used for tube). In this study, this technology has also been applied to peroxide-crosslinked EPDM. The obtained reclaimed rubber was found to be a mixture of two components; one is a linear chain which is soluble in toluene and whose average molecular weight is one third of that of the original raw rubber, and the other is a very loosely crosslinking network whose effective network chain density is about one fiftieth of that of the peroxide-crosslinked virgin rubber. The ratio of linear chain component and loosely crosslinking network component was approximately 3 to 2. The reclaimed rubber can be cured with sulfur- accelerator curing system. The sulfur-crosslinked reclaimed rubber shows good mechanical properties nearly equal to those of sulfur-crosslinked virgin one.