3.4.2. Atomic force microscopy (AFM)
To further explore the nature of interactions between PLA and
PLA/MCC composites, the composites were observed by AFM, and
the results are presented in Fig. 5. From the figure, it can be clearly
seen that the inclusions of MCC into the PLA matrix significantly
change the surface topography of the pure PLA. The pure PLA
surface is relatively smooth (Fig. 5(a)). However for PLA/MCC composites
(Fig. 5(b)–(d)) the cluster between PLA and MCC are readily
apparent and the surface cluster a clearly observed when the MCC
contents are increased. The cluster features are interpreted as the
result of aggregation of the MCC, or as PLA coated MCC. Similar
result was earlier reported by Saxena, Elder, Pan, and Ragauskas
(2009).