Abstract: An improved polymer devolatilization apparatus including a flat plate heater having a multiplicity of flat plates defining a plurality of channels, each channel having a substantially uniform height but varying width over its length, each channel including three zones:a first zone in operative communication with the polymer solution supply device, characterized by decreasing width as a function of distance from its beginning,a second zone beginning at the terminus of the first zone, characterized by at least one occurrence of a restrictive cross-sectional area, anda third zone beginning at the end of the second zone and terminating at a liquid/vapor collection and separation region operating at reduced pressure, said third zone characterized by increasing width as a function of distance from its beginning, and provided further that the ratio of maximum width of the third zone to the maximum width of the second zone is from 2:1 to 20:1.

Abstract: Hydroperoxidized rubber-containing polymers are prepared in a process wherein a rigid phase polymer is prepared by polymerization of one or more free radically polymerizable monomers in the presence of a hydroperoxidized rubbery intermediate in a well stirred back-mixed reactor operating under essentially homogeneous conditions at a solids content of from about 30 to about 75 percent by weight, and an initial rubber content in the feed of from about 5 to about 12 percent by weight.