The biomedical advantages of a polystyrene surface are combined with a low effective density in a new class of microspheres. Polybead® Hollow Microspheres are spherical styrene / acrylic beads supplied in suspension. A relatively dense shell of a polystyrene based copolymer is formed around a void in the particle. Sphere voids are water-filled in the as-supplied 5% solids aqueous suspension, and the water-filled particle will have an effective density near 1.0 g/cm3. Water is lost from the void upon drying as the particles are slightly porous. This results in a hollow particle with a shell approximately 0.10µm thick. Surfactants on the surface of the spheres help stabilize the particles.
Composition: Styrene / acrylic
Effective Density: ~1.0 g/cm3