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

• Published in: Polymer (Guilford) Vol. 185; p. 121963
• Main Authors: Niwa, Saori, Ogawa, Tatsuya, Ogoe, Shinji, Teramoto, Yoshikuni
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 17.12.2019; Elsevier BV
• Subjects: Biomedical materials; Calorimetry; Cellulose; Compatibility; Compatibilizers; Crystalline cellulose; Differential scanning calorimetry; Evaluation; Fracture surfaces; Interface/interphase; Localization; Maleic anhydride; Maleic anhydride-modified polypropylene; Mechanical properties; Particulate composites; Physical properties; Polypropylene; Rheological properties; Surface tension; Thickness; Transmission electron microscopy; Wetting; Maleic anhydride-modified polypropylene; Interface/interphase; Cellulose
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2019.121963

To 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. [Display omitted] •Maleic anhydride modified PP (MAPP) as a compatibilizer.•DSC estimated cellulosic filler wetting by MAPP with different acid contents.•TEM visualized MAPP localization at filler/PP matrix interface.•MAPP with high acid content coated the cellulosic filler tightly.•Physical properties of the composites were correlated with MAPP characteristics.