Abstract: An asymmetric semipermeable membrane and processes for the manufacture thereof are disclosed. The membrane comprises at least one hydrophobic polymer and at least one copolymer based on acrylonitrile, at least one sulphonic monomer which is optionally salified, and optionally at least one non-ionic, ionizable, olefinically unsaturated monomer. The membrane is useful in the treatment of biological fluids such as plasma or blood, especially using plasmapheresis, or with the aid of an artificial kidney using hemodialysis and/or ultrafiltration.

Abstract: The invention provides semi-permeable hollow fibres of symmetrical type and of homogeneous microporous structure, with a smooth internal surface, which are obtained by cooling a solution of a copolymer of acrylonitrile and an olefinically unsaturated comonomer carrying optionally salified sulphonic acid groups, in a polar organic solvent with an adjuvant, to give a thermally reversible gel, followed by washing, stretching and relaxation treatments. The new hollow fibres have improved haemocompatibility and are useful in treating blood by haemodialysis, ultrafiltration and/or plasmapheresis.

Abstract: Apparatus/process for the withdrawal and return of liquid materials from a donor source, comprising means for withdrawing whole blood from a mammalian donor; a membranous blood filtration cell which includes a membrane separator/filter, a compartment downstream therefrom for receiving a blood plasma fraction and a compartment upstream thereof for receiving a blood cellular component fraction; conduit means for communicating the withdrawal means and an inlet end of the upstream compartment; a collection vessel; conduit means for communicating an outlet end of said upstream compartment and said collection vessel; means for determining the volume of liquid material withdrawn from the donor source during a withdrawal stage; means for back-filtering and returning liquid material from said collection vessel to the donor source; a second collection vessel; and conduit means for communicating an outlet end of the downstream compartment and the second collection vessel.

Abstract: Multicellular materials having excellent heat-resistance are provided by preparing granules of1. a prepolymer obtained from:A. a product containing an imide group, which isA. a bis-imide of the formula: ##STR1## in which D represents a radical of the formula: ##STR2## WHEREIN Y represents H, CH.sub.3 or Cl, m is 0 or 1, and A represents a divalent organic radical containing 2 to 30 carbon atoms, orB. a mixture comprising a bis-imide of formula (I) and a mono-imide of the formula: ##STR3## in which D is as defined above and R represents a hydrogen atom or a monovalent organic radical containing 1 to 20 carbon atoms, andB. an amine product which isA. one or more polyamines containing from 2 to 5 primary or secondary amino groups, at least one of these groups being primary, orB. a mixture comprising one or more polyamines as defined under a) and one or more primary and/or secondary monoamines and/or one or more secondary polyamines,2. a pore-forming agent and3.