Sub-micrometer thermoplastic vulcanizates obtained by reaction-induced phase separation of miscible mixtures of poly(ethylene) and alkyl methacrylates

Sub-micrometer (mu m) thermoplastic vulcanizates (TPVs) with cross-linked rubber particles with sizes ranging from 70 to 400 nm were prepared by reaction-induced phase separation (RIPS) of initially miscible blends of poly(ethylene) (PE), lauryl methacrylate (LMA) and divinylbenzene (DVB). Cross-linking under static conditions led to (partial) connectivity of the rubber particles via chemical bridging of grafted PE chains. Dynamic preparation conditions caused the connected structure to break-up, which led to a significant enhancement of the mechanical properties and the melt processability. The addition of 25-80 wt% extender oil resulted in a reduced complex viscosity and yield stress in the melt, without deteriorating the mechanical properties. The relatively good elastic recovery and excellent ultimate properties of these high hardness TPVs may be explained by the sub-pm rubber dispersions. (C) 2008 Elsevier Ltd. All rights reserved.