Polypropylene/polyamide blend featuring mechanical interlocking via controlled interfacial diffusion and recrystallization

The prevalent way to enhance interface interaction of immiscible polymer blend is adding some low molecular weight compatibilizers with “soft” nature, unfortunately throwing negative effects on the final mechanical strength. Here, an interfacial interlocking design strategy for immiscible polypropylene (PP)/polyamide (PA) blend is proposed. The formation process involves aryl amide-based compounds firstly were selectively enriched in PA phase, followed by controlled release and recrystallization at the subsequent annealing process, into fiber-like crystals at the interface. Accordingly, the blend featuring mechanical interlocking was successfully prepared, where the interfacial grown fibers functioned as interlocks to integrate the two immiscible components via large interfacial friction. Furthermore, the density and dimension of the interfacial fibers were tailored by adjusting the annealing temperatures. Specially, at the elevated temperature, the large and dense fibers were generated at the interface to offer stronger interfacial friction, which in turn strengthened the interfacial interaction. The interfacial topological regulation can effectively solve the interfacial problems and also can extend broadly to the other immiscible bi-phase systems.