Effect of supercritical carbon dioxide on PMMA/rubber and polystyrene/rubber blending: Viscosity ratio and phase inversion.(Statistical Data Included): An article from: Polymer Engineering and Science

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From the author: Supercritical carbon dioxide (sc[CO.sub.2]) was added during blending of polystyrene or poly(methy1-methacrylate) (PMMA) and a rubber impact modifier (SP 2207). The resulting blend morphologies were compared. The compounding took place in a Leistritz ZSE-27 twin-screw extruder at 100 RPM, at a temperature of 200[degrees]C, and with 2.0 wt% [CO.sub.2] injection. The viscosity reduction of PMMA, polystyrene, and SP 2207 was measured using a slit die rheometer attached to the twin-screw extruder. A viscosity reduction of up to 84% was seen with PMMA, 70% with polystyrene and 30% with SP 2207. The solubility of [CO.sub.2] in these polymers was measured in a high-pressure vessel at 200[degrees]C and 13.78 MPa (2000 psi). A solubility of 5.79 wt% [CO.sub.2] was seen with PMMA, 3.65 wt% with polystyrene, and 2.60 wt% with SP 2207. The injection of [CO.sub.2] reduced the size of the dispersed rubber phase in both polystyrene and PMMA. For both blends (polystyrene/SP 2207 and PMMA/SP 2207) with and without the injecti on of [CO.sub.2], the extruder length for phase inversion was shortened by about L/D = 4, or 10% of the total extruder length. The impact strength for a 70/30 polystyrene/SP 2207 blend was increased by 26% by the addition of [CO.sub.2]. The improvement in impact strength was not as large for blends of PMMA and SP 2207.

Citation Details
Title: Effect of supercritical carbon dioxide on PMMA/rubber and polystyrene/rubber blending: Viscosity ratio and phase inversion.(Statistical Data Included)
Author: Mark D. Elkovitch
Publication:Polymer Engineering and Science (Refereed)
Date: December 1, 2001
Publisher: Society of Plastics Engineers, Inc.
Volume: 41 Issue: 12 Page: 2108(18)

Article Type: Statistical Data Included

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