Wetting and localization of compatibilizers in biocomposites: A nanoscale evaluation and effects on physical properties

Publication date: Available online 4 November 2019Source: PolymerAuthor(s): Saori Niwa, Tatsuya Ogawa, Shinji Ogoe, Yoshikuni TeramotoAbstractTo elucidate the efficacies that have been empirically interpreted on compatibilizers, the interfacial adhesion in cellulosic filler/polypropylene (PP) biocomposites was investigated at the nanoscale. Maleic anhydride-modified PP (MAPP) with different weight fractions (wMA) of acid-modified groups was added as the compatibilizer. Two nanoscale aspects were examined: the degree of wetting of the compatibilizer on the microcrystalline cellulose (MCC) filler and the extent of compatibilizer localization. The degree of wetting was systematically evaluated via differential scanning calorimetry and was found to increase with wMA. Transmission electron microscopy revealed that MAPP was located near MCC particles in MCC/MAPP/PP composites via thermal kneading, while only a part of the loaded MAPP was localized at the of MCC/PP interface. The MAPP layer thickness was ∼50 nm and independent of wMA. The increased degree of wetting with increasing wMA improved the rheological reinforcement effect, the withdrawal of MCC filler on the fracture surface, and the mechanical properties. Thus, MCC was probably tightly coated with the MAPP with high wMA and the interfacial tension with the PP matrix was decreased.Graphical abstract
Source: Polymer - Category: Chemistry Source Type: research