Recycling of EPDM waste. II. Replacement of virgin rubber by ground EPDM vulcanizate in EPDM/PP thermoplastic elastomeric composition

Virgin ethylene propylene diene monomer (EPDM) rubber in a thermoplastic el astomeric blend of polypropylene (PP) and EPDM rubber was substituted by gr ound EPDM vulcanizate of known composition, after which the mechanical prop erties of the raw EPDM/waste EPDM/PP blends were determined. The ratio of t he rubber content in the waste EPDM (r-W-EPDM) to the raw EPDM (R-EPDM) in the blends was varied from 0 : 100 to 45 : 55. Attempts to replace higher a mounts (> 45%) of R-EPDM by W-EPDM failed because of processing difficulty. Although a drop in mechanical properties of the blends was observed at low er loadings of W-EPDM, the properties showed improvement at intermediate W- EPDM loadings. The R-EPDM/W-EPDM/PP blends were found to be reprocessable. (C) 2001 John Wiley & Sons, Inc.