Abstract: Hollow thermoexpandable particles or microspheres are provided that contain hydrocarbon blowing agents and have a shell polymer that can be softened at the onset of the expansion temperature and solidified at a higher temperature (thermoset) in an expanded state. Preferably, the microspheres have a shell of thermally expandable and thermally crosslinkable polymer and a hollow interior that contains a hydrocarbon liquid that boils at a temperature below the heat activated crosslinking temperature of the polymer shell. The crosslinking of the shell polymer during or after expansion, which is heat activated at an elevated temperature, can solidify the shell polymer and, then, maintain the expanded volume of the microspheres. The thermoexpandable thermoset polymer particles are useful in insulation, packaging, for making foam materials such as polyurethane or polyisocyanurate rigid foams.

Abstract: A dye, such as a fluorescent dye, is incorporated into polymer microparticles using a solvent system composed of a first solvent in which the dye and the microparticle polymer are soluble, a second solvent in which the dye and the microparticle polymer are not or only weakly soluble, and a third solvent in which the dye and the microparticle polymer are not or only weakly soluble. The first and second solvents are immiscible with each other, or at most partially miscible. The third solvent is miscible with the first and second solvents. The formulation provides substantially complete partitioning of the dye to the microparticles. The method may be used to obtain dyed polymer microparticle formed of cross-linked or non-cross-linked polymers. Libraries are provided comprising two or more sets of microparticles of different dye loadings.

Abstract: A dye, such as a fluorescent dye, is incorporated into polymer microparticles using a solvent system composed of a first solvent in which the dye and the microparticle polymer are soluble, a second solvent in which the dye and the microparticle polymer are not or only weakly soluble, and a third solvent in which the dye and the microparticle polymer are not or only weakly soluble. The first and second solvents are immiscible with each other, or at most partially miscible. The third solvent is miscible with the first and second solvents. The formulation provides substantially complete partitioning of the dye to the microparticles. The method may be used to obtain dyed polymer microparticle formed of cross-linked or non-cross-linked polymers. Libraries are provided comprising two or more sets of microparticles of different dye loadings.

Abstract: Microspheres are described which have a shell of thermally expandable polymer and a hollow interior that contains a fluorinated hydrocarbon that boils at a temperature below the melting point of the polymer, and contains an organic ester or ether or ketone. The ester or ether or ketone improves the quality of microsphere product. The expandable particles are useful in insulation, packaging, for expanding other polymer such as polytetrafluoroethylene, and the like.

Abstract: Polycarbonate compositions having excellent mechanical and thermal properties as well as high impact resistance are prepared by mixing an aromatic polycarbonate resin with a structured multiphase composite impact modifier. The structured multiphase composite impact modifier has a core particle of a rubbery particle having a glass transition temperature below -20.degree. C. and a second glassy polymer having a glass transition temperature above 20.degree. C., where the second polymer is present as discontinuous regions on the surface of the core particle.