Abstract: The invention relates to a process for the preparation of a material of composite structure containing a thermoplastic plastic and a fibrous polymer skeleton material, having a high modulus of torsional shear, good shockproofness and being processable by the formation technologies of thermoplastic plastics. According to the invention one proceeds in such a way that the fibrous polymer skeleton material is treated with a resin mixture consisting of an unsaturated polyester resin and a vinyl monomer in an amount of 1-80 percent by weight, related to the skeleton material.The use of the polyester as adhesion-intermediator considerably improves the homogeneity of the material of composite structure, it makes the substance processable without pregranulation on an extruder with a broad slot or a calendrette, and leads to plates the shockproofness of which significantly exceeds that of plates prepared without such intermediator.

Abstract: Two plastics which were heretofore impossible to combine, can be combined with each other if the one to be added is converted to a porodin gel by heating the same at a temperature of at least 180.degree. C. with a substance that does not dissolve the polymer, and then cooling to below 120.degree.. The porodin gel can then be easily admixed with the other plastic material in an amount of 1 to 50% by weight, preferably 5 to 20% by weight based on the weight of the modified plastic material. Examples are the incorporation of polyethylene or polypropylene or polymethyl methacrylate in polyvinyl chloride, or the incorporation of polystyrene in polypropylene, or the incorporation of polymethyl methacrylate in polyethylene.