Properties and Nano-observation of Natural Rubber with Nanomatrix Structure - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 324

In order to focus on the defect to understand a reason why the dramatic increase in
the plateau modulus occurs after annealing the rubber with the nanomatrix structure,
we made the three-dimensional image of the nanomatrix at extremely high magnifi-
cation. Figure 10 and Figure 11 show the three-dimensional TEMT images of nano-
matrix structure before and after annealing the rubber with nanomatrix structure at
130°C, respectively. The image of a through view in Figure 10 apparently showed the
connected nanomatrix before annealing. However, the edge views revealed that a part
of the nanomatrix was disconnected; that is, many lumps of granular polystyrene gath-
ered to form the nanomatrix structure. A distance between the polystyrene-granules
was less than several nm, suggesting a flocculation of the granules. In contrast, after
annealing, the granules were partly fused to each other (Figure 11). Thus, the anneal-
ing may bring about the connected nanomatrix.
Figure 10. Orthogonal cross-sectional views and three-dimensional TEMT image of the rubber with
the nanomatrixstructure. Box size is 289 nm, 434 nm, 65 nm, where dark domains represent natural
rubber and bright domains represent polystyrene. In a XY through view, the nanomatrix is confirmed
to be about 15 nm in thickness, which is disconnected to each other in XZ and YZ edge views.
The three-dimensional TEMT image reveals that a part of the matrix was connected to each other,
whereas the other was disconnected, before annealing.