Photon Factory Activity Report 2004 #22 Part B (2005)
Materials Science

9C, 15A/2003G275

Orientation Structure of Semi-Crystalline Block Copolymer Polybutadiene-bpoly(ε-caprolactone) Induced by Crystallization
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Katsuhiro YAMAMOTO*, Shigeo HARA, Yusuke SUGINO, Masashi Kurata1, KaoriUsami1, Ken1111ichi TANIDA , Yumi KUROMIYA ,Yuhei KONOKAWA, Shigeru OKAMOTO , and Shinichi
2
SAKURAI
1
NagoyaInstitute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
2
Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan

Introduction
Crystallization behavior in confinement space such as
microphase separation among some semicrystalline block
copolymer has been often studied by many researchers,
including study on structure development of crystalline in
crystallizable component. In this study, the crystalline
structure (orientation) of semi-crystalline block
copolymer, polybutadiene-b-poly(ε-caprolactone) (PB-bPCL), was investigated by small and wide-angle X-ray
scattering (SAXS & WAXS) in oriented microphaseseparated structure.
Experimental
Sample Preparation
PB-b-PCL was synthesized by sequential anionicpolymerization. Number averaged molecular weight,
molecular weight dispersed index, and volume fraction ofPCL were 9300, 1.7, and 63. PCL melting point Tm was
60 °C by obtained DSC. In molten state above Tm, thesample showed a lamellae microphase separated structure
confirmed by SAXS measurement. The lamellar
microdomain was oriented in the melt-state by applicationof an elongational flow field in a channel (10mm wide)
die at 75 °C (above Tm of PCL) for 1 min, hold for 10 min,and the sample was crystallized isothermally at 40, 25,0 °C and quenched to liquid nitrogen temperature. The
sample thickness decreased from 2 to 1 mm by theorientation.
Result and Discussion
Figure 1 shows SAXS patterns of PB-b-PCL
crystallized at 298K for an hour, which was measured at
298K, (a) edge view, (b) end view, and (c) through view.
In the each view, y-direction corresponds to the flow
direction, z-direction is a weighted direction andperpendicular to the y, x-direction is perpendicular to theboth directions. In the edge view, scattering peaks wereobserved in equatorial and meridian direction, but thepeaks in the meridian were weaker. Scattering position of
the each direction was quite different. In the end view, thesame tendency was obtained, but the peaks in themeridian were less observable than those in edge view. In
the through view, a relatively weak ring (slightly oriented)
pattern was observed. The domain spacing dcorresponding to equatorial peaks in the end and edge

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Users' Reportviews was calculated to be 28.2 nm. The d due tomeridian peaks was 22.8 nm, which coincides with the dfrom the rings in the through view. From SAXS
measurement indicates an anisotropic structure, thelamellae microdomain was considered to be oriented(parallel) to the flow direction. The rings in the throughview can be assigned to the crystalline-amorphousalternative structure in the microdomain, no scatteringfrom a lamellae microphase separation was observed.
To elucidate the orientation structure of microphaseseparation and crystalline, we measured 2D WAXS. As aresult of WAXS measurements, c-axis of crystalline ofPCL in the microdomain was predominantly oriented
parallel to the lamellae microdomain plane. At lower
crystallization temperature, a probability of theorientation of the c-axis perpendicular to the lamellae
plane increased. Increasing Tc induced more dominantorientation parallel to the microdomain plane of the c-axis.
The orientation of crystalline of PCL was opposite
behavior reported previously in the semicrystalline block
1copolymers. The mechanism of present study is still
under investigation.
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Figure 1. 2D SAXS patterns of PB-b-PCL crystallized at298K.
References[1] S.Z.D.Cheng et al., Macromolecules 34, 1244 (2001)[2] S.Gido et al., Macromolecules 34, 7009 (2004)* yamamoto.katsuhiro@nitech.ac.jp