Avaliação da incorporação de nanofibrilas celulósicas, nanoargila e emulsão de ceras na confecção de embalagens multicamadas

Abstract

The objective of this work was to evaluate the effects of coating by deposition of cellulose nanofibrils, nanoargila and wax emulsion of bee and carnauba in the grammage, thickness, water vapor permeability and wettability of kraft papers. The suspensions were deposited by spatulation on kraft paper of 60 g/m² until they reached a grammage of 80 g/m², where treatments containing only layers of cellulose nanofibrils (NF) and layers of nanoargila (MMT) were prepared, treatments with layers of cellulose nanofibrils overlaid by carnauba wax emulsion (NF/EC) and bee (NF/EA), treatments with layers of nanoargila also overlaid by emulsion layers of carnauba wax (MMT/EC) and bee wax (MMT/EA) and treatments with only the emulsions of the waxes (EC and EA). The treatments were compared with the kraft papers of 60 g/m² (Ref 60) and 80 g/m² (Ref 80). The scanning electron microscopy images of the surface and the cross sections showed a significant reduction of the voids present in the reference paper (60 g/m²). With the increase of the wax emulsion layer, EC and EA showed a reduction of 87% and 69% in the water vapor permeability (PVA) of 60 g/m² paper, respectively. When compared to the 80 g/m² paper, this reduction in PVA was even higher (96% and 90%, respectively). When the layers of emulsions were associated with layers of nanoargila (MMT/EC = 2.3 g.mm/dia.m².KPa and MMT/EA = 4.4 g.mm/dia.m².KPa) these obtained better PVA results than when associated with layers of cellulose nanofibrils (NF/EC = 5.2 g.mm/dia.m².KPa and NF/EA = 6.8 g.mm/dia.m².KPa) for PVA.. As for the wettability of the packages, only EA, MMT/EA and NF/EA reached hydrophobicity, with contact angles equal to 98.9º; 98.7 ° and 93.6 °. However, the results showed how the emulsion layers of carnauba and bee waxes have improved the hydrophobicity and water vapor barrier properties of multilayer papers, and how the combination with layers of cellulose nanofibrils and nanoargila influences these properties.