TY - JOUR
T1 - Enabling reprocessability of ENR-based vulcanisates by thermochemically exchangeable ester crosslinks
AU - Algaily, Bashir
AU - Kaewsakul, Wisut
AU - Sarkawi, Siti Salina
AU - Kalkornsurapranee, Ekwipoo
N1 - Funding Information:
The authors would like to acknowledge the financial supports from the Higher Education Research Promotion and Thailand’s Education Hub for Southern Region of ASEAN Countries Project Office of the Higher Education Commission, as well as from the Natural Rubber Innovation Research Institute (grant number SCI6201170s), Prince of Songkla University.
Funding Information:
The authors would like to acknowledge the financial supports from the Higher Education Research Promotion and Thailand?s Education Hub for Southern Region of ASEAN Countries Project Office of the Higher Education Commission, as well as from the Natural Rubber Innovation Research Institute (Grant number SCI6201170s), Prince of Songkla University. The authors would like to acknowledge the financial supports from the Higher Education Research Promotion and Thailand?s Education Hub for Southern Region of ASEAN Countries Project Office of the Higher Education Commission, as well as from the Natural Rubber Innovation Research Institute (grant number SCI6201170s), Prince of Songkla University.
Publisher Copyright:
© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
PY - 2021/4/1
Y1 - 2021/4/1
N2 - A reprocessable elastomeric vulcanisate based on Epoxidised Natural Rubber with 50 mol-% epoxide content (ENR-50) was evloved by applying a self-assembled network based on thermochemically exchangeable ester crosslinks to the system. Hydrolysed Maleic Anhydride (HMA) as crosslinking substance in the presence of 1,2-DiMethylImidazole (DMI) as esterification accelerator and Zinc Acetate Dihydrate (ZAD) as transesterification catalyst was employed to generate the exchangeable ester crosslinking system. A sulphur-cured ENR-50 vulcanisate possessing a permanent sulphide crosslinking network was prepared as reference. Based on the results from cure characteristic and chemical structure analyses, the ENR-50 crosslinked with HMA behaves as a dynamic network because of a transesterification reaction catalysed by ZAD, promoting an exchangeable crosslinking network in the system. This dynamic network contributes to an intermolecular rearrangement of the ester crosslinking bonds at elevated temperatures, enabling interfacial self-adhesion and so reprocessability of the vulcanisates. The obtainable vulcanisates can be reprocessed, yielding relatively high retention of mechanical properties compared to their pristine counterpart. The interfacial self-adhesion and reprocessability of the vulcanisates have shown to significantly be improved with a higher loading of ZAD and elevated temperatures. This concept essentially shows a prospect towards developing e.g. novel recyclable and self-healing systems for elastomers.
AB - A reprocessable elastomeric vulcanisate based on Epoxidised Natural Rubber with 50 mol-% epoxide content (ENR-50) was evloved by applying a self-assembled network based on thermochemically exchangeable ester crosslinks to the system. Hydrolysed Maleic Anhydride (HMA) as crosslinking substance in the presence of 1,2-DiMethylImidazole (DMI) as esterification accelerator and Zinc Acetate Dihydrate (ZAD) as transesterification catalyst was employed to generate the exchangeable ester crosslinking system. A sulphur-cured ENR-50 vulcanisate possessing a permanent sulphide crosslinking network was prepared as reference. Based on the results from cure characteristic and chemical structure analyses, the ENR-50 crosslinked with HMA behaves as a dynamic network because of a transesterification reaction catalysed by ZAD, promoting an exchangeable crosslinking network in the system. This dynamic network contributes to an intermolecular rearrangement of the ester crosslinking bonds at elevated temperatures, enabling interfacial self-adhesion and so reprocessability of the vulcanisates. The obtainable vulcanisates can be reprocessed, yielding relatively high retention of mechanical properties compared to their pristine counterpart. The interfacial self-adhesion and reprocessability of the vulcanisates have shown to significantly be improved with a higher loading of ZAD and elevated temperatures. This concept essentially shows a prospect towards developing e.g. novel recyclable and self-healing systems for elastomers.
KW - molecular engineering
KW - polymer network
KW - polymer recycle
KW - self-healing
KW - Vulcanisation
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85103604649&partnerID=8YFLogxK
U2 - 10.1080/14658011.2021.1896093
DO - 10.1080/14658011.2021.1896093
M3 - Article
AN - SCOPUS:85103604649
SN - 1465-8011
VL - 50
SP - 315
EP - 328
JO - Plastics, Rubber and Composites
JF - Plastics, Rubber and Composites
IS - 7
ER -