In the case of nanocomposites, the PLA + 10 wt.% CNF cellulose structures seemed poorly distributed, and CNF remained present in aggregation. The CNF appeared to be better distributed in the PLA + 5 wt.% CNF with the PHB carrier system. This carrier system contained smaller agglomerates which were more evenly distributed in the
material compared to PLA + 10 wt.% CNF. The CNF agglomerates appeared less compact and showed good interfacial adhesion to the PLA. These results are in agreement with the discussed mechanical test analysis. This research also showed that CNF were able to enhance the interfacial adhesion and influence the compatibility between PLA and PHB matrices . The changes in the morphology of the composites can be associated with the changes in the viscosity, and the CNF did not lead to changes in the composite morphology at low CNF loadings. The change in the morphology of PLA + 10 wt.% CNF and PLA + 5 wt.% CNF could be connected to the increase of composite viscosity