The effects of functional azo initiator on PMMA and polyurethane IPN systems. II. The influence of the interface and the matrix structure on the mechanical properties

The mechanical properties of materials prepared by a new method for modifying the structure of polyurethane/poly(methyl methacrylate) (PU/PMMA) interpenetrating polymer networks (IPNs) by using a reactive azo initiator were investigated by means of tensile test, tear test, and dynamic mechanical thermal analysis (DMTA) measurement. The structures of these IPNs were similar to the particulate filled elastomers. It was found that the reactive initiator, which could form blocks of PMMA within the PU matrix (rubber), changed both the filler‐matrix interface and the matrix structure. The mechanical properties of these IPNs were dominated by the matrix structure and the interface.