6.2 Rubber Reinforcement by In Situ Silica
113
(c) α=2
(b) α=1.5
(a) α=1
(d)
(e)
Stretching
direction
Fig. 6.6 Speculated morphological change of silica particles in the in situ silica-filled IR
nanocomposite upon deformation (modified Fig. 4 in Ref. [55])
SPring-8 [55]. Simultaneously, measured tensile stress is plotted against elongation
ratio, i.e., α = l/l 0 , where l 0 is the initial length and l is that of during the uniaxial
tensile elongation of the specimen. The 2D-SAXS measurement was conducted at
every elongation ratio of α = 0.5, using X-ray of wavelength = 0.15 nm, with
irradiation time of 50 ms onto the specimen, and a CCD camera was used for the
detection of X-ray intensity.
From the analysis of the 2D-SAXS patterns, the change of silica morphology by
the uniaxial elongation is estimated as schematically displayed in Fig. 6.6. Just before
the elongation (α = 1), the pattern naturally shows amorphous due to the random
distribution of the silica as shown in (a). At α = 1.5 (b), the pattern shows anisotropy
due to the shifts of silica on elongation as shown in Fig. 6.6d. The distance between the
particles widens in the tensile direction, and it narrows in the perpendicular direction
(equator direction) of stretching. At α = 2, the scattering data suggests a four-spot
pattern, which is in accordance with the paper by Rharbi et al. [66]. That is, they
reported 2D images of deformed nanocomposites which were obtained by a computer
simulation technique. They proposed two processes on the appearance of the fourspot pattern; either some long aggregates buckle under the lateral compression, or
the space in the perpendicular direction to the stretching between two aggregates is
filled up by another aggregate that forced between them. Taking their results into
account, the route from (b) to (d) via (c) and (e) is reasonably estimated. Namely a
formation of buckling structure of in situ silica particles was formed by stretching.
This morphological change in in situ silica particles was ascribable to the elongation
in the stretching direction and the compression from the lateral directions occurring
simultaneously during uniaxial stretching. This estimation is supported by atomic
force microscopy (AFM) results. Further elongation brought about the shift of the
peak top to the smaller angle side, and it passed the detective boundary of this
experimental setting at α = 2.5.
113
(c) α=2
(b) α=1.5
(a) α=1
(d)
(e)
Stretching
direction
Fig. 6.6 Speculated morphological change of silica particles in the in situ silica-filled IR
nanocomposite upon deformation (modified Fig. 4 in Ref. [55])
SPring-8 [55]. Simultaneously, measured tensile stress is plotted against elongation
ratio, i.e., α = l/l 0 , where l 0 is the initial length and l is that of during the uniaxial
tensile elongation of the specimen. The 2D-SAXS measurement was conducted at
every elongation ratio of α = 0.5, using X-ray of wavelength = 0.15 nm, with
irradiation time of 50 ms onto the specimen, and a CCD camera was used for the
detection of X-ray intensity.
From the analysis of the 2D-SAXS patterns, the change of silica morphology by
the uniaxial elongation is estimated as schematically displayed in Fig. 6.6. Just before
the elongation (α = 1), the pattern naturally shows amorphous due to the random
distribution of the silica as shown in (a). At α = 1.5 (b), the pattern shows anisotropy
due to the shifts of silica on elongation as shown in Fig. 6.6d. The distance between the
particles widens in the tensile direction, and it narrows in the perpendicular direction
(equator direction) of stretching. At α = 2, the scattering data suggests a four-spot
pattern, which is in accordance with the paper by Rharbi et al. [66]. That is, they
reported 2D images of deformed nanocomposites which were obtained by a computer
simulation technique. They proposed two processes on the appearance of the fourspot pattern; either some long aggregates buckle under the lateral compression, or
the space in the perpendicular direction to the stretching between two aggregates is
filled up by another aggregate that forced between them. Taking their results into
account, the route from (b) to (d) via (c) and (e) is reasonably estimated. Namely a
formation of buckling structure of in situ silica particles was formed by stretching.
This morphological change in in situ silica particles was ascribable to the elongation
in the stretching direction and the compression from the lateral directions occurring
simultaneously during uniaxial stretching. This estimation is supported by atomic
force microscopy (AFM) results. Further elongation brought about the shift of the
peak top to the smaller angle side, and it passed the detective boundary of this
experimental setting at α = 2.5.