Behavior of Polymers Filled with Monodisperse Polymeric Beads

摘要

Techniques have been developed for preparing crosslinked spherical polymer beads,monodisperse in size, composed of polystyrene and derivatives, polymethyl methacrylate (PMMA), polyethyl methacrylate, polybutyl methacrylate and polymethylacrylonitrile. Control of the crosslink density gradient was achieved by semi-continuous copolymerization. Monodisperse bead diameters are controlled between 150-800 nm in a single stage synthesis, with sizes reproducible to nm in a given run and crosslink densities vary from 1-20 mol%. Particle nucleation onto preexisting polymer seeds was conducted in a multistage polymerization yielding compositionally complex beads up to 4 microns in diameter. Beads are characterized by a wide variety of techniques. A new procedure has been developed to determine the crosslink density by equilibrium swelling on an ultrafiltration membrane.