Abstract:
What is described herein is an improved precipitation polymerization process and copolymer products produced thereby. The process herein is carried out by charging a reactor with a solvent in which the copolymer product is substantially insoluble over the entire compositional range of the copolymer, preferably heptane or cyclohexane, and a polymerization initiator, heating to 50° to 150 °C, agitating, and then simultaneously feeding selected amounts of a vinyl lactam and a polymerizable carboxylic acid into said reactor below the surface of the solvent while continuing to agitate the mixture to precipitate the copolymer from solution as a fine, white powder, and recovering the copolymer of defined composition.
Abstract:
A continuous, solvent-free process for obtaining solvent-free, fine white powders of high molecular weight alternating copolymers of maleic anhydride and a C1-C4 alkyl vinyl ether, without odor or taste, having the molecular structure (A-B)n, where A is maleic anhydride, B is an alkyl vinyl ether and n is an integer indicative of the molecular weight of the copolymer, which comprises feeding alkyl vinyl ether as reactant and solvent in excess over the desired 1:1 mole ratio of A:B in the copolymer, molten maleic anhydride and a free radical initiator, continuously at predetermined feeding rates into a reactor heated at a reaction temperature of about 50° to 100 °C, holding the reactants in the reactor for a predetermined average residence time, withdrawing reaction product, residual alkyl vinyl ether and initiator at the same rate as the feed rate of reactants into the reactor, stripping residual alkyl vinyl ether from the reaction product, drying the copolymer obtained of any remaining traces of alkyl vinyl ether, and recycling recovered alkyl vinyl ether back into reactor as reactant and solvent.
Abstract:
A continuous, solvent-free process for obtaining solvent-free, fine white powders of high molecular weight alternating terpolymers of maleic anhydride, a C1-C4 alkyl vinyl ether and isobutylene, without odor or taste.
Abstract:
Tablets of a poorly compressible drug are made by direct compression using a binder composition which is a polymer, preferably a copolymer of polyvinylpyrrolidone (PVP) and vinyl acetate (VA), having a defined glass transition temperature (Tg), admixed with a plasticizer, e.g. an organic ester or polyol, which reduces the Tg of the copolymer by at least 10°C. The binder composition and the drug are directly compressed into a tablet of predetermined hardness and friability, and at an acceptable compression force.
Abstract:
Procédé de polymérisation par précipitation et produits copolymères ainsi produits. On met en oeuvre le procédé en chargeant un réacteur d'un solvant dans lequel le produit copolymère est insoluble sur la totalité de l'éventail de composés du copolymère, de préférence de l'heptane ou du cyclohexane, et d'un initiateur de polymérisation, par chauffage entre 50° et 150 °C, par agitation et ensuite par acheminement simultané de quantités sélectionnées d'un lactame vinylique et d'un acide carboxylique polymérisable dans ledit réacteur au-dessous de la surface du solvant, tout en continuant à agiter le mélange afin de précipiter le copolymère tiré d'une solution, sous forme d'une fine poudre blanche, et à récupérer le copolymère de la composition définie.
Abstract:
A continuous, solvent-free process for obtaining solvent-free, fine white powders of high molecular weight alternating copolymers of maleic anhydride and a C1-C4 alkyl vinyl ether, without odor or taste, having the molecular structure (A-B)n, where A is maleic anhydride, B is an alkyl vinyl ether and n is an integer indicative of the molecular weight of the copolymer, which comprises feeding alkyl vinyl ether as reactant and solvent in excess over the desired 1:1 mole ratio of A:B in the copolymer, molten maleic anhydride and a free radical initiator, continuously at predetermined feeding rates into a reactor heated at a reaction temperature of about 50 DEG to 100 DEG C, holding the reactants in the reactor for a predetermined average residence time, withdrawing reaction product, residual alkyl vinyl ether and initiator at the same rate as the feed rate of reactants into the reactor, stripping residual alkyl vinyl ether from the reaction product, drying the copolymer obtained of any remaining traces of alkyl vinyl ether, and recycling recovered alkyl vinyl ether back into reactor as reactant and solvent.
Abstract:
A continuous, solvent-free process for obtaining solvent-free, fine white powders of high molecular weight alternating terpolymers of maleic anhydride, a C1-C4 alkyl vinyl ether and isobutylene, without odor or taste.