Models of a Degrading Polymer Network

Abstract

Regular, two- and three-dimensional networks of linear analogs to elastic polymeric chains were degraded randomly in an attempt to establish a relationship between the force produced by a constantly strained network and the number of chain scissions. This behavior is important for the quantitative interpretation of chemical stress relaxation data. The models showed that the initial modulus of the three-dimensional networks should vary as the number of crosslinkages (tetrafunctional) to the 4/3 power. The initial rate of decay of the relative force for random main chain cleavage was (in the limit of infinite network size) equal to twice the rate of decay of the relative number of chains between the crosslinkages. At high degrees of degradation (relative number of chains between crosslinkages equal to 1 / e) the models indicated that the relative force would approach zero in the limit of infinite network size. The behavior of the models showed that the force decay of a degrading network is considerably more rapid than had been generally thought.