The Dissociation Mechanism of Poly‐α‐methylstyrene (PAMS) Dimers Induced by Spin Polarization

Abstract

AbstractTo understand the last step of degradation mechanical of the poly‐α‐methylstyrene (PAMS), we studied the fracture mechanism of PAMS dimers. The calculations show that the PAMS dimer has two different spin‐polarized effects dissociation reaction paths. Interestingly, one path is ferromagnetic coupling triplet state, which needed to overcome the energy barrier is about 0.80 eV and corresponding to an endothermic reaction. While, another path is the antiferromagnetic coupling spin‐polarized singlet state, which needed to overcome the energy barrier is only about 0.03 eV with an exothermic reaction. Both the electron density difference and the energy decomposition show that the interaction between the two monomers is relatively strong in the transition state (TS) of singlet. This is because, in the TS of singlet state, the distance between the two monomers is closer. Our results highlight that the last dissociation of PAMS and another polymer may be through the antiferromagnetic path and which able to complete spontaneously and quickly. This finding removes a possibility of mass spectrometry experiments that origin of degradation of dimer products, and is helpful to understand the degradation process for materials.