Abstract: A process for removing vaporizable constituents from high-viscosity solutions or melts of thermoplastics by continuous evaporation along a heated devolatilization zone and separation of the vapor phase from the liquid phase in a downstream separating vessel. The plastic solution or melt is first heated stepwise in increments, in the devolatilization zone, while the product is in the form of thin layers from about 0.5 to 4 mm, so as to maintain a temperature difference of less than 50.degree. C.

Abstract: A process and an apparatus for heating or cooling very viscous solutions or melts of thermoplastics in the form of thin layers. The plastic solution or melt is spread under the temperature conditions of the feed solution or melt, and the thin layers are heated stepwise so that the temperature difference between the heat transfer medium and the solution or melt is at all times less than 50.degree. C. and preferably less than 20.degree. C. Viscous solutions or melts of thermoplastics can be heated or cooled rapidly and uniformly under gentle and controlled conditions, to prepare the solutions or melts for further treatment in conventional equipment.

Abstract: A process for admixing additives to plastics and simultaneously removing volatile constituents in a horizontal devolatilizing extruder. Taken in sequence in the direction of flow, the additives are first introduced into the devolatilizing extruder from above, and the plastic melt, solution or dispersion is then introduced from below, while the bulk of the volatile constituents are withdrawn from the devolatilizing extruder at an orifice located vertically above the point at which the plastic is fed in. The process permits the removal of volatile constituents with simultaneous admixture of additives during aftertreatment of plastics, in a single step and at very high throughputs.

Abstract: Acrylonitrile or monomer mixtures containing acrylonitrile are purified by treating them with alkaline reacting compounds followed by distillation. The products are particularly suitable for the manufacture of acrylonitrile polymers showing improved color stability.

Abstract: A continuous process for the polymerisation of olefinically unsaturated monomers in bulk or in solution in which at least a portion of the low-viscosity materials to be fed to the polymerization zone is thoroughly mixed with a portion of the high-viscosity contents of the polymerization zone in a mixing zone disposed upstream of the polymerization zone, which mixture is then continuously fed to the polymerization zone. The resulting polymers have a uniform composition and a narrow molecular weight distribution. They may be converted to shaped articles by thermoplastic methods.