Production of partially silane-crosslinked PP-copolymer foams

This contribution introduces a new method for the radically initiated silane-grafting of polypropylene (PP) copolymers adding a chemical foaming agent, but keeping the degradation of the native chains to a minimum. This results in foamable, with water crosslinkable materials which are no longer thermoplastic after the silane-bridges have developed since they have three-dimensional network structure that in contrary to the native polymer gives a remarkably higher melt elasticity and stability. These modified structured solids recieve, compared with native PP, a much finer foam structure with closed cells and at the same time improved chemical, mechanical and thermal resistance.