Exploring the thermomechanical properties of peroxide/co-agent assisted thermoplastic vulcanizates through temperature scanning stress relaxation measurements |
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Authors: | Asit Baran Bhattacharya Anagha M Gopalan Tuhin Chatterjee Norbert Vennemann Kinsuk Naskar |
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Affiliation: | 1. Rubber Technology Centre, Indian Institute of Technology Kharagpur, Kharagpur, India;2. Department of Chemical Engineering, University of Groningen, Groningen, The Netherlands;3. Faculty of Engineering and Computer Science, University of Applied Sciences Osnabruck, Osnabruck, Germany |
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Abstract: | Temperature scanning stress relaxation (TSSR) measurement of peroxide vulcanized polymer blends of polypropylene (PP) and ultrahigh molecular-EPDM (UHM-EPDM) rubber has been performed to study the thermomechanical behavior of thermoplastic vulcanizates (TPVs). Co-agents play crucial roles in the enhancement of properties of TPVs. Different types of co-agents (Triallyl cyanurate-TAC; N, N-m-phenylene-dimaleimide-HVA2; zinc dimethacrylate-ZDMA; and in-situ formed zinc dimethacrylate-ZMA) have been explored in this work. TSSR study shows that higher T50 and T90 values have been achieved in ZMA co-agent assisted-TPV. Higher TSSR-index (RI) value was also found for the same co-agent ZMA, indicating higher elastic behavior. TSSR result supports the mechanical and rheological properties, and it is found that the ZMA and ZDMA show higher mechanical strength. Cross-linked-density calculated by modified Flory–Rehner equation and the cross-link-density as obtained from TSSR method have been compared and the trend was found to be the same. Stress relaxation study shows the slow relaxation-phenomena of the ZMA-TPV with slowest relaxation-time (θr) than the other TPVs, which correlates with superior material strength. Thermogravimetric analysis proves that there is a difference in degradation temperature of the blends at approximately 5–10°C. Ultrahigh molecular weight-EPDM/PP based TPVs reveal superior thermomechanical and physico-mechanical properties with ZMA and ZDMA co-agent over TAC and HVA2. These ultrahigh molecular weight-EPDM based TPVs can be used in automotive seals/strips, hoses, bellows, and 2 K-molds for automotive applications. |
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Keywords: | co-agent stress relaxation temperature scanning stress relaxation index thermomechanical properties thermoplastic Vulcanizates |
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