Reactive modification of polymers is a well-established way for tuning of a number of properties in different single and multiphase materials. Nevertheless this method has not realized their potential. One of the main reasons for this lack is the difficulty to control temperature fields during processing, taking into account that the most reactions are heat induced. Electron induced reactive compounding – developed at the Institute of Polymer Research Dresden (IPF) – is an alternative to heat induced reactive compounding with unique possibilities for process tuning. Another new idea is the inductive heating using a high-magnetic-field pulse to initiate susceptor based chemical reactions to generate composite materials. The fundamentals of this new idea will be described by model reactions. The potentials and the limits of classical heat induced, electron induced and high-magnetic-field induced reactive modification will be shown, interpreted and evaluated. An outlook for innovative ideas will be given.