Thermal Expansion Behavior of Thermally Expandable Microspheres Prepared by Suspension Polymerization Using P(AN‐MMA‐MAA) Core/Shell

Thermally expandable microspheres (TEMs) have widespread industrial applications. In this study, high heat resistant and largely expandable TEMs have been synthesized by suspension polymerization. Microspheres were prepared with acrylonitrile (AN) as the main monomer. Initial thermomechanical analysis of TEMs containing AN and methyl acrylate (MA) showed good thermal expansion, leading to the investigation of the polymerization using various monomers at variable weight ratios. TEMs with co‐polymer AN, methyl methacrylate (MMA), and methacrylic acid (MAA) were investigated for the first time. They displayed wider heating range and larger expansion rate than the microspheres with MA monomer. The effect of varying amounts of monomer ratios on the thermal expansion behavior is discussed.