The aim of this study is to investigate the crosslinking of different polyolfins with the support of a modified mineral filler. The modified filler, talcum, acts as a crosslinking agent and improves the crosslinking network. Therefore, a thermal initiator is linked to the talcum surface. During the extrusion process the initiator decomposes and radicals are formed. These radicals support the crosslinking process between the polymer chains. To produce the crosslinking agent, two steps were necessary. The first step was the grafting of alkoxysilanes onto the talcum surface. The next step was the linking between the initiator and the silanes grafted onto the talcum surface. To optimize the crosslinking network, two different polyolefin blends were used. The aim was to investigate the influence of the different chain branching behaviour of the polymer network on the crosslinking process. Therefore, compression molded plates out of the polymer blends and the modified talcum were produced and analyzed with a plate/plate rheometer.