Block Copolymer Micelles for Nucleation of Microcellular Thermoplastic Foams

摘要: The use of block copolymer micelles as novel nucleating agents for foaming thermoplastics is explored. Diblock copolymers can self-assemble into a large number spherical micelles, making them promising nucleants the production microcellular foams with >10 9 cells/cm 3 . Different types A-B diblock were added to polystyrene matrix in low concentrations, and resulting blends foamed batch process using carbon dioxide blowing agent. Polystyrene-b-poly- (ethylene propylene) polystyrene-b-poly(methyl methacrylate) diblocks not effective nucleants. Diblocks containing poly(dimethylsiloxane) core showed bimodal cell size distribution small increase concentration. increased solubility (PDMS), reduced surface tension PDMS, lowered minimum work bubble formation None an concentration proportional potential present. Block able sufficiently lower nucleation. They are too size, still agglomerate larger, nonequilibrium structures, have contact angles due high most polymers.