実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF	 Experimental Report

提出日 Date of Report

課題番号 Project No.

装置責任者 Name of responsible person

2014A0009

Yasuhiro Miyake

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Studies on Dynamcs of Highly Crosslinked Rubber by µSR

D1

実験責任者名 Name of principal investigator

実施日 Date of ExperimentToshiji Kanaya

June 19-22, 2014

所属 Affiliation
Institute for Chemical Research, Kyoto University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Materials and sample preparation
The details of materials used in the present study are summarized in Table 1.
a matrix rubber.

We used polybutadiene (PB) as

Zinc diacrylate (ZDA) and dicumyl peroxide (DCP) were used as a crosslinking agent and apolymerization initiator of butadiene, respectively.

The components were mixed on a 6-inch two-roll mill, andthey were molded into sheet 1 mm thick at 170 ℃ for 20 min. The glass transition temperature (Tg) of Sample
A and B are 168.6 K and 168.1 K, respectively. The Elastic modulus at 293 K of Samples A and B are 4.0 MPa
and 104.6 MPa, respectively.
Table 1.: Detail of components of samples used in present study.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results. If you failed to conduct experiment as planned, please describe reasons.
Measurements
The Longitudinal field (LF) µSR experiment was performed using a beamline D1 instrument installed atJ-PARC in the temperature range between 70 and 280 K. External magnetic field range is between 10 to 2000
G. Each sample is set onto the sample holder. The obtained raw asymmetry data were corrected for theinstrumental constant and for the backgrounds from the sample holder.

1

Results
The LF-µSR spectra of Samples A at 70 K and 280 K
are shown in Fig. 1 and 2, respectively. We used thedouble stretched exponential fitting function (1) as firsttrial.

(β)

(β)

f (t ) = A1 exp − (Γ1t ) 1 + A2 exp − (Γ2 t ) 2 + B (1)where Γ 1 and Γ2 are relaxation rates, β and β are thestretch parameters, A1, A2 and B are the fittingparameters. Fig. 1 and 2 show the observed andcalculated spectra of Sample A at 70 K and 280 K,
respectively. The observed µSR spectra were well fitted
to Equation 1. According to Pratt et al.[1] and ourprevious sutdy[2], the dynamics of muon is thought tocorrespond to the dynamics of crosslinked polymer.
The obtained relaxation rate Γ1 of Sample A at 70 Kand 280 K by fitting is shown in Fig. 3. At 70 K, below
glass transition temperature of polymer Tg (=168.6 K),
Γ1 is almost constant between 10 to 500 G, anddecrease above 500 G. This result means that thedynamics of polymer is not affected by external
magnetic field below 500 G because micro-Brownian
motion of polymer chain is frozen below Tg. On theother hand, at 280 K, above Tg, Γ1 decrease withincreasing external magnetic field, suggesting thatdynamics of polymer is affected by external magnetic
field because the frozen micro-Brown motion ofpolymer chain is thawed and the polymer chain is able
to move actively above Tg. Furthermore, the value ofΓ1 at 280 K is higher than that of Γ1 at 70 K. This result
is also caused by higher mobility of polymer chainabove Tg.
1270K. Solid curves are the results of fits.

Fig. 2.: LF-µSR spectra of Sample A at280K. Solid curves are the results of fits.

100Relaxation rate Γ (kHz)[1] F. L. Pratt et al., Physica B 289-290(2000)625.
[2] T. Kanaya et al., KEK-MSL Report 2013,2013B0016, in press.

Fig. 1.: LF-µSR spectra of Sample A at

● Γ 1 at 70K● Γ 1 at 280K

1010.1

0.01
10100

1000

10000

Magnetic field (G)Fig. 3.: Relaxation rate Γ1 and Γ2 ofSample A at 70K and 280K as a functionof magnetic field.
2