The ISM contains both CR and PAH. The frontal impact of a single heavy CR with one PAH, strips out many electrons. The highly charged species then relax by multifragmentation, potentially feeding the interstellar medium with hydrocarbon chains. I will present results of calculations for this process. The IAE model was used for collisional purposes while a new microcanonical model was used for fragmentation. Both models agree with experiments. The production rate of low hydrogenated hydrocarbon chains (Nc = 5-15) is found to be within 0.1 to 1 zeta depending on the size and morphology of the PAH, and on the adopted content of heavy particles in the impinging CR flux.