Quantitative characterization of silica dispersion and rubber-filler interactions in in-situ sol-gel derived rubber nanocomposites by advanced SEM image analysis

The distribution of nanofillers and their agglomerates at different levels and scales within polymer nanocomposite is a very important aspect for assessing mechanical and physical reinforcement capabilities of polymer nanocomposites. To characterize mechanical and physical properties of polymer nanocomposites, three characteristics, such as dispersion, continuity and interfacial coverage of nanofillers in polymer nanocomposites were studied and their corresponding indices were proposed through image processing techniques on scanning electron microscopy (SEM) images of polymer nanocomposites. The SEM images were smoothed and thresholded to obtain the corresponding binary images, depicting the distribution of fillers and their agglomerates (white pixels) over the polymer base (black pixels). The image processing results showed high agreement with the experimental values of physicochemical behavior of the nanocomposites such as volume fraction of silica filler into the rubber network, crosslinking value, Q f / Q g and mechanical properties such as modulus and tensile strength.