Cellulose nanofibrils (CNFs), which are attracting increasing attention as sustainable biomass nano-objects, are believed to be hydrophilic. Recently, aqueous counter collision (ACC) has been used to produce Janus-type amphiphilic cellulose nanofibrils (ACC-CNFs) from various cellulosic raw materials. In the current study, ACC-CNFs were preferentially adsorbed onto hydrophobic isotactic polypropylene (i-PP) microparticles and linear low-density polyethylene (LLDPE), which demonstrated their characteristic amphiphilicity. This was achieved by simply mixing the constituents together in aqueous media. The products were visualized by confocal laser microscopy (CLMS). Thermodynamic measurements obtained by differential scanning calorimetry revealed that the melting points of i-PP/ACC-CNFs and LLDPE/ACC-CNFs were lower than those of the untreated polymers, which indicates interactions between the ACC-CNFs and the polymer surfaces. Coating the polymer particles with the ACC-CNFsas confirmed by CLMSappeared to reduce their melting points. This finding demonstrates the possibility of a novel fusion between synthetic polymeric materials and biomass nano-objects.

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This study attempts to clarify thermodynamic quantification on interaction between poly(vinyl alcohol) (PVA) and wood-derived cellulose nanofibrils (CNFs) obtained by aqueous counter collision (ACC) method. Aqueous mixtures of PVA/ACC-CNFs with various fiber widths were cast as the target materials. The interfacial interactions between the two components were characterized through thermodynamic evaluation of the crystalline PVA component as a probe in the cast mixture. As the result, surface properties of the ACC-CNFs found to reflect on the crystallization behavior of the interacted PVA component, resulting in dual nano-size effects of either diluent or nucleating agent. Melting point depression behaviors of the PVA component indicated that ACC-CNFs with thinner widths induced nucleation effects on PVA crystallization, whereas ACC-CNFs with ca. 100 nm in width encouraged diluent effects on PVA components. It is noted that this trend found to be reverse to the case for PVA/ACC-CNFs of bacterial nanocellulose previously reported.