68
4 Nanofiller Dispersion in Rubber as Revealed by 3D-TEM
Fig. 4.11 Visualization of the silica networks by skeletonizing the 3D-TEM images. Hydrophilic
silica; NR-P-10, -30, and -80: Hydrophobic silica; NR-P-10RX, -30RX, and -80RX (from Fig. 9 in
Ref. [8]). See Video 4.4 in Supplemental Electronic Material
to be explained: Toward the higher aggregate (including the agglomerate), the primary aggregates encircled by bound rubber are forming a cluster. Namely, they are
connected via rubber layer of 1.3 nm thickness as suggested by d p in Fig. 4.9. (In
the case of carbon black, the thickness is different. See next section.) As shown in
Fig. 4.8 defining d p , the two center of gravities of the adjacent aggregates of 1.3 nm
distance are connected by a line and continue this lining on every neighboring pair
in a higher aggregate. The lining is, of course, to be done only on the adjacent pair
of 1.3 nm distance. Figure 4.11 shows this lining to result in the skeletonization [8],
where jungle gym-like skeletons of various sizes are seen.
In the images of lower silica contents, color difference indicates an independent
cluster. While almost all clusters are connected at 30 phr in the RX series, hydrophilic
VN series shows the presence of local clusters, i.e., higher aggregates at 30 phr. At
80 phr, both RX and VN series suggest the agglomeration stage. In other words,
gelation of the primary aggregates is completed to give a nanofiller network. Qualitatively speaking, this finding is in conformity with the results shown in Fig. 4.7,
and both are explainable by the higher filler-to-filler interaction of VN silica than
RX silica. Detailed observation of the images in Fig. 4.11 reveals the nanofiller networks being composed of cross-linking chains, branching chains, and isolated chains
(though only a few in Fig. 4.11) just like cross-linked rubber networks.
Figure 4.12 schematically represents a network structure of the nanofiller network
in general [8, 11]. The black arrow shows connection to the overall network struc-
4 Nanofiller Dispersion in Rubber as Revealed by 3D-TEM
Fig. 4.11 Visualization of the silica networks by skeletonizing the 3D-TEM images. Hydrophilic
silica; NR-P-10, -30, and -80: Hydrophobic silica; NR-P-10RX, -30RX, and -80RX (from Fig. 9 in
Ref. [8]). See Video 4.4 in Supplemental Electronic Material
to be explained: Toward the higher aggregate (including the agglomerate), the primary aggregates encircled by bound rubber are forming a cluster. Namely, they are
connected via rubber layer of 1.3 nm thickness as suggested by d p in Fig. 4.9. (In
the case of carbon black, the thickness is different. See next section.) As shown in
Fig. 4.8 defining d p , the two center of gravities of the adjacent aggregates of 1.3 nm
distance are connected by a line and continue this lining on every neighboring pair
in a higher aggregate. The lining is, of course, to be done only on the adjacent pair
of 1.3 nm distance. Figure 4.11 shows this lining to result in the skeletonization [8],
where jungle gym-like skeletons of various sizes are seen.
In the images of lower silica contents, color difference indicates an independent
cluster. While almost all clusters are connected at 30 phr in the RX series, hydrophilic
VN series shows the presence of local clusters, i.e., higher aggregates at 30 phr. At
80 phr, both RX and VN series suggest the agglomeration stage. In other words,
gelation of the primary aggregates is completed to give a nanofiller network. Qualitatively speaking, this finding is in conformity with the results shown in Fig. 4.7,
and both are explainable by the higher filler-to-filler interaction of VN silica than
RX silica. Detailed observation of the images in Fig. 4.11 reveals the nanofiller networks being composed of cross-linking chains, branching chains, and isolated chains
(though only a few in Fig. 4.11) just like cross-linked rubber networks.
Figure 4.12 schematically represents a network structure of the nanofiller network
in general [8, 11]. The black arrow shows connection to the overall network struc-