Abstract: A modular, constructional heating unit, useful, e.g., for the fabrication of interior partitions, is comprised of a panel member provided with at least one elongate rectilinear cavity, the longitudinal axis of such cavity being parallel to a face surface of the panel, said cavity being exteriorly communicating at one or both of its ends, and said cavity containing an electrical heating element.

Abstract: A heating element is comprised of [A] a shaped, electrically insulating substrate, said substrate including a reinforced polyimide composite, [B] a continuous, electric resistor element in entwining relationship with, and at least partially inlain within said composite [A], said electric resistor element being coated with a thermostable electrically insulating coating, and [C] means for coupling said electric resistor element [B] with an electric power source. Techniques for the fabrication of such heating elements are also disclosed.

Abstract: A shaped article is disclosed consisting essentially of a matrix of thermoplastic polymer in which there is dispersed, in the form of particles of mean diameter less than 200.mu., a polyimide resin comprising the reaction product of (a) a bis-imide of the formula: ##STR1## and (b) a diamine of the formula:NH.sub.2 -- B -- NH.sub.2 (II)in which formulae the symbol Y represents H, CH.sub.3 or Cl, and the symbols A and B, which may be identical or different, represent a phenylene or cyclohexylene radical or a radical ##STR2## wherein T represents --CH.sub.2 --, --C(CH.sub.3).sub.2 --, --O--, --SO.sub.2 -- or --S--, the bis-imide/diamine molar ratio being greater than 1, and the amount of polyimide resin constituting from 25 to 80% of the weight of the mixture of matrix + polyimide resin. The thermoplastic polymer may be e.g., polyethylene, polypropylene, ethylenepropylene copolymers or ethylene-tetrafluoroethylene copolymers.