Abstract: Spiro(bis)indane polycarbonates, including homo- and copolycarbonates, are devolatilized by extrusion under conditions of low viscous dissipation and low residence time. By this method, volatile impurities including spiro(bis)indane cyclic dimer may be removed.

Abstract: A feed pipe is provided for introducing highly reactive monomers into a continuous reactor to effect polymerization of such reactive monomers. The feed pipe has concentric tubes forming a central flow channel and an annular flow channel which are sized to insure laminar flow within said tubes. The feed pipe is particularly useful for feeding melts of organic dianhydride and organic diamine into an extrusion reactor for polyetherimide preparation.

Abstract: Polyetherimides are formed by the dry blending of organodianhydride, organic diamine, and chain stopper and the polymerization of the dry-blended mixture in a continuous, steady state reaction, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating and cooling, evacuation of water of reaction, and material conveyance means in order to achieve a steady state necessary for continuous production of a uniform polymeric product.

Abstract: Polyetherimides are formed by the blending of a first melt of organic dianhydride and a second melt of organic diamine and the resulting blend is polymerized in a continuous, steady state manner, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating, evacuation of water of reaction, and transfer sections in order to achieve the steady state necessary for continuous production of a substantially uniform polyimide.

Abstract: Polyetherimides are formed by the dry blending of organodianhydride, organic diamine, and chain stopper and the polymerization of the dry-blended mixture in a continuous, steady state reaction, employing an extruder reactor as the reaction chamber. The extruder reactor is provided with means for heating and cooling, evacuation of water of reaction, and material conveyance means in order to achieve a steady state necessary for continuous production of a uniform polymeric product.

Abstract: A process for molding an article having preselected portions formed of different organic plastic materials is described which comprises (a) positioning at least a first skin material essentially free of reinforcing fillers and at least a first core material containing reinforcing fillers in an elongated heating zone at preselected locations of the materials relative one to the other; (b) heating the materials to a temperature sufficient to melt each of the materials while maintaining said materials at their preselected relative positions; (c) exerting a force against an end of the melted materials; (d) linearly moving the melted material in response to the force through the heating zone and into a mold cavity; and (e) cooling at least the first skin and first core materials in the mold cavity. The process can be employed advantageously to provide substantially distortion free injection molded products having glass fiber filled large thin walled sections.