Abstract: A multiple shell structure and a method of manufacturing such structure wherein a hollow glass microsphere is surface treated in an organosilane solution so as to render the shell outer surface hydrophobic. The surface treated glass shell is then suspended in the oil phase of an oil-aqueous phase dispersion. The oil phase includes an organic film-forming monomer, a polymerization initiator and a blowing agent. A polymeric film forms at each phase boundary of the dispersion and is then expanded in a blowing operation so as to form an outer homogeneously integral monocellular substantially spherical thermoplastic shell encapsulating an inner glass shell of lesser diameter.

Abstract: This invention relates to polymer blends having improved hydrolytic stability which comprise, in admixture, (1) a linear aromatic polyester of monomer residues consisting essentially of residues of a dicarboxylic acid and a bisphenol, and (2) a SAN polymer.