In the last decades techniques have been developed to conduct tensile tests on single polymeric molecules. The target of currently ongoing research at the institute of solid mechanics is the development of a mechanistic model able of reproducing the results of these experiments. Eventually the knowledge of the mechanical behaviour of a single polymer chain can be used to deduce a model of a polymeric network. Further, we also aim to the degradation and erosion in polymers. The modelling is motivated by a micromechanical description. Since degradation leads to the erosion of polymers, the modelling approach will consider the dependency of both effects. Here, degradation is modelled as a chemo mechanical problem. In order to simulate degradation and erosion in complex geometries, the modelling approach is embedded into a finite element framework.