Glass fibre reinforced polypropylene (PP) composites show reduced fibre- matrix- adhesion in comparison to thermosetting systems. The thermoplastic consolidation of PP involves no curing, only in the glass fibre interface a chemical reaction between the silane coupling agent and the maleic anhydride grafted polypropylene is take place. In this study, the impact of the electron beam treatment on fibre- matrix- adhesion of specially modified crosslinkable toughened polypropylene and alkylene functionalized glass fibres were investigated. The PP matrix crosslinking behavior was evaluate as well as a systematic comparison of non-, amino, alkyl and alkylene functionalized single fibres was done in order to study their influence on the local interfacial strength parameters. In comparison to the state of the art modification using amino functionalized glass fibres in polypropylene/maleic anhydride grafted polypropylene, an +20% enhanced local interfacial shear strength and a +80% higher critical energy release rate were observed by using alkylene functionalized glass fibres.