Sub-micrometer TPVs based on crosslinking-induced phase separation of polycaprolactone/oligoetherdimethacrylate blends
Event:176th Technical Meeting Location: Pittsburgh, PA Date: October 13, 2009 Author: Martin Van Duin,* Roy l'Abee, Han Goossens and Marloes Verbruggen Paper Number: 169
Reaction-induced phase separation (RIPS) of initially miscible mixtures of poly(8- caprolactone) (PCL) and elastomer precursors based on difunctional methacrylate resins was applied to prepare thermoplastic vulcanizates (TPVs) with rubber particle sizes ranging from 80 to 900 nm. The radicals formed by the peroxide decomposition initiate the formation of a crosslinked rubber network with gel contents exceeding 90 %, but also abstract hydrogen atoms from the aliphatic moieties in PCL. This leads to the formation of PCL-grafted rubber particles, which show a high nucleating efficiency for crystallization of the PCL matrix. It is demonstrated that the tensile and elastic properties of these TPVs are determined by a complex interplay of the morphology, the type of elastomer precursor, the extent of PCL grafting, the crystallinity and the lamellar thickness. The materials showed a rheological behavior that is typical for TPVs, for which the melt changes from an elastic to a viscous behavior above a critical stress.