Morphology of some immiscible polymer blends made by free radical polymerization of one component in an electric field
Abstract
Immiscible binary polymer blends were made by polymerizing a monomer in which a different polymer was dissolved in the presence of a DC or AC electric field. Scanning electron microscopy (SEM) was used to study the morphology of the resulting polymer mixture. Gel Permeation Chromatography (GPC) was used to determine the molecular weight of the polymer made under different conditions. One typical system started with 5 - 20 wt% polystyrene (PS) dissolved in methyl methacrylate (MMA); the MMA was then free radically polymerized using the UV-sensitive initiator, 2,2-dimethoxy-2-phenylacetophenone (DMPA) at room temperature. Another system started with 5 - 20 wt% poly(tetrahydrofuran) dissolved in styrene; the styrene was then free-radically polymerized using 2,2-azobisisobutyronitrile (AIBN) at 60 ^oC. The electric field used during the polymerization ranged from 2 to 10 kV/cm, DC or 10 Hz AC. The dispersed phase had dimension of 1 - 50 μm it was spherical in the absence of an electric field but ellipsoidal in some elecrtric fields. While the more polar dispersed phase had its long axis aligned in the field direction, the less polar dispersed phase had its long axis aligned perpendicular to the field direction. The effect of electric field on molecular weight distribution will be discussed. The morphology of the PS-PMMA system was also compared with the solution casting method previously studied in this lab. (supported by NSF, DMR-9521265)
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2002
- Bibcode:
- 2002APS..MARM33033L