Photon Factory Activity Report 2014 #32 (2015) B

BL-10C/2014G011

Crystallization Behavior of Double Crystalline Block Copolymer/Crystalline
Homopolymer BlendsSatoru Gondo, Satoshi Osawa, Hironori Marubayashi, and Shuichi Nojima*
Department of Organic and Polymeric Materials, Graduate School of Science and Engineering,Tokyo Institute of Technology, H-125, 2-12-1 Ookayama, Meguro-ku Tokyo 152-8552, Japan
1 Introduction
We have recently examined the crystalline morphology
formed in binary blends of poly(ε-caprolactone)-blockpolyethylene diblock copolymers (PCL-b-PE) and PCL
homopolymers, and found that the morphology depended
significantly on the miscible state between PCL-b-PE andPCL homopolymers before crystallization [1]. In thisstudy, we investigate the crystallization behavior of PCLchains (i.e., PCL blocks in PCL-b-PE and PCL homopolymers), where the PCL homopolymer exists with different
miscible states in the microphase-separated melt. Fromthese results, we try to elucidate a substantial differencein the crystallization behavior of PCL chains on the basisof the miscible state of PCL homopolymers [2].
2 Experiment
Samples The PCL-b-PE and PCL homopolymers are thesame samples used in our previous study [1]. We
prepared two binary PCL-b-PE/PCL homopolymer blends,Blend 1 and Blend 2, where the PCL homopolymer waslocalized between PCL blocks in the lamellar
microdomain structure in Blend 1, whereas it washomogeneously mixed with PCL blocks in Blend 2.
Measurements The isothermal crystallization behavior of
PCL chains was examined using simultaneous SAXS/WAXD techniques with synchrotron radiation. The experiment was performed at beam line BL-10C in KEK-PF.
3 Results and DiscussionFigure shows the typical time-resolved SAXS (a) ands*aWAXD (b) curves for Blend 1 during isothermal
crystallization at 38 oC. The SAXS curve at 120 oC has
several scattering peaks arising from the lamellar
microdomain structure (not shown in Figure a). By
quenching to 38 oC, it turns into another one with diffuse
scattering peaks (corresponding to the SAXS curve at t =0 s in Figure a) due to the advance crystallization of PE
blocks. This diffuse scattering peak grows remarkably by
the subsequent crystallization of PCL chains (shown by
an arrow). Two distinct scattering peaks (indicated by s*and 2s*) can be observed after the complete
crystallization of PCL chains (at t = 1170 s), the positionsof which exactly correspond to a ratio of 1 : 2, suggestinga crystalline lamellar morphology is formed in the system.
The WAXD curves have three appreciable diffraction
peaks (Figure b). Because the diffraction pattern from PE
crystals is extremely similar to that from PCL crystals,
these peaks are combined diffractions arising from PEand PCL crystals.
The fundamental parameters characterizing thecrystallization behavior were extracted from SAXS andWAXD curves, and we clarified the difference in thecrystallization behavior of PCL chains between Blend 1and Blend 2.
References[1] S. Gondo et al., Polymer 54, 6768 (2013).
[2] S. Gondo et al., Polym. J., in press (2015).
* snojima@polymer.titech.ac.jpb

(110)

Intensity (a.u.)

(200)
(210)

2s*

1170 1170 

Crystallization
Time (s)

Crystallization
Time (s)

0

0
20

s (nm-1)

25

30

2θ (degree)

Figure. Typical time-resolved SAXS (a) and WAXD (b) curves for Blend 1 during isothermal
crystallization at 38 ℃. s* in (a) represents the wavenumber of primary peak position and (110), (200), and(210) in (b) are the diffraction planes of PCL crystals.