実験番号：201802015（4 シフト）BL8S3

WAXS and SAXS study of low-fouling carbon nanotube polypropylene nanocomposites
Rodolfo Cruz-Silva,1 Hiroki Kitano,2 Kenji Takeuchi,1 and Morinobu Endo.1
1. Aqua Center of Innovation Shinshu University and Institute of Carbon Science, Faculty of Engineering,
Shinshu University, Nagano, Japan.
2. Kitagawa Industries Co., Kasugai City, Aichi, Japan
Keywords: Nanocomposite, orientation, crystallinity, polyolefin.
1．Background and research purpose
In recent years, a lot of attention has been paid to low-fouling materials that can find use in technologies such as
biomedical materials, food technology, membrane and marine coatings.1 Among the most common materials wefind polypropylene, a commodity polymer with a low cost and excellent mechanical properties and processability.
Several studies have shown that modification of this polymer with nanofillers help to reduce the fouling.2, 3 In
our group, we prepared a composite containing carbon nanotubes and it has shown promising results. As acomplementary part of the fouling study, we must understand the microstructure of the composite and corelate
the surface composition with the fouling performance.
2．Experiment contents
Polypropylene was melt-mixed with carbon nanotubes in different mass fractions. Then, net-like samples with ashape typical of a membrane spacer were injected. Samples of about 1 mm of radius were cut from this material
and analyzed by WAXS and SAXS at the Aichi Synchrtrohon facility at the BL8S3 line. The resulting patterns
were analyzed using Fit2D software.4
3．Results and discussion
The Figure 1 shows the WAXS patterns obtained for the plain polypropylene material (Figure 1a) and the carbon
nanotube composite containing 15 wt% of the nanotubes (Figure 1b). We observed a higher scattering in thecomposite due to the highly crystalline CNT material embedded in the composite and a possible increase incrystallinity. The 001 peak of graphitic carbon is absent due to the perpendicular orientation of the nanotubes tothe beam, so it might be very weak and/or overlapped by the polymer peaks. However, the SAXS patterns (notshown) evidence a reduction of the spherulite size upon addition of the carbon nanotubes. The WAXS patterns
before integrations show a clear biaxial orientation due to the orientation of the polymer during the injection
flow. This orientation affect is markedly higher in the carbon nanotubes as evidenced in the Figure 1b. Indeed,carbon nanotubes have been shown to orient during injection due to shear stress,5 improving in this way themechanical properties of the nanocomposite. The peak-to-peak ratio of the crystalline peaks to the amorphous
phase area shows a large increase after adding the carbon nanotubes, suggesting a nucleating effect. Thesesamples will be examined by calorimetry in order to calculate the crystallinity degree and compare with thevalues obtained by X-ray diffraction. These results shown that carbon nanotubes are well dispersed and aligned
within the polypropylene matrix and support a possible improvement on the mechanical properties.

Figure 1. Radially integrated Wide-angle X-ray scattering patterns of a) plain polypropylene and b)
polypropylene and carbon nanotubes nanocomposite (15 wt % loading). The insets show the original WAXS
patterns before integration.

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