Upgrading Toughness and the Glass Transition Temperature of Polydicyclopentadiene upon Addition of Styrene–Ethylene–Butylene–Styrene Thermoplastic Elastomer

Polydicyclopentadiene (PDCPD) thermoset, as commonly prepared by ring-opening metathesis polymerization (ROMP), features excellent mechanical, thermal, and anticorrosion properties, but it lacks ductility and toughness. In situ addition of 2 to 8 wt % of styrene–ethylene–butylene–styrene (SEBS) thermoplastic during material preparation slightly alters the stiffness while improving its toughness and ductility. Remarkably, 4 wt % SEBS increases the PDCPD glass transition temperature Tg up to 165 °C (i.e., +7 °C). Calorimetric analyses suggest that addition of SEBS, acting as a plasticizer during molding, reduces the polymerization time of DCPD. This result offers a simple method to adjust PDCPD impact properties and to increase its Tg.