Investigation of Interfacial Diffusion in PA/PP-g-MAH Laminates Using Nanoscale Infrared Spectroscopy

The characterization of polymer-polymer interfaces is of great interest to understand the diffusion process and chemical interactions in polymeric multiphase systems. This study investigated the formation of the interface layer between polyamide (PA) and polypropylene (PP) and its dependency on the maleic anhydride (MAH) content in PP. New insights with a very high level of details on the formation of the interfacial layer are obtained by employing a special technique of atomic force microscopy (AFM) combined with infrared (IR) for chemical imaging at nanoscale spatial resolution. This enables the determination of the interface thickness and even the observation and visualization of the diffusion gradient across the PA/PP interface layer. Combined with classical investigation methods such as interfacial energy and rheology, the method of nano-IR spectroscopy represents a very powerful tool to obtain more insights and a deeper understanding of the interfacial phenomenon in multiphase polymeric systems.