Supplementary Information

Size: px

Start display at page:

Download "Supplementary Information"

Christine Blankenship
5 years ago
Views:

1 Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C. This journal is The Royal Society of Chemistry 2016 Supplementary Information Improved electromechanical properties of NBR dielectric composites by poly(dopamine) and silane surface functionalized TiO 2 nano-particles Dan Yang, ab Mengnan Ruan, bc Shuo Huang, bc Yibo Wu, ab Shuxin Li, ab Hao Wang, ab Yuwei Shang, ab Bingyao Li a, Wenli Guo,* ab Liqun Zhang* c a Department of Material Science and Engineering, Beijing Institute of Petrochemical Technology, Beijing , China b Beijing Key Lab of Special Elastomeric Composite Materials, Beijing , China c Department of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing , China *To whom correspondence should be addressed. W. Guo (gwenli@bipt.edu.cn) or L. Zhang (zhanglq@mail.buct.edu.cn)

2 Table S1. Curing characteristics and Mooney viscosity of pure NBR and NBR composites filled with different contents of filler. Sample S max S min S Mooney (dn m) (dn m) (dn m) (ML100 o C(1+4)min) 0 phr phr TiO phr TiO 2 -(PDA+KH570)

3 Table S2. Summary of electromechanical properties of pure NBR and NBR composites Sample Elastic Dielectric Dielectric Maximum Breakdown modulus constant loss strain strength (Mpa) (1 khz) (1 khz) (%) (kv/mm) 0 phr phr TiO phr TiO phr TiO phr TiO 2 -(PDA+KH570) phr TiO 2 -(PDA+KH570) phr TiO 2 -(PDA+KH570)

4 R-O-O-R.. or HC. 2 OR O 2 =C( 3 )CO Si(O 3 ) 3 R-O-O-R. OR 2 O C( 3 )CO Si(O 3 ) OR or OR 2 O 2 ( 2 )CO Si(O 3 ) 3 OR 2 O ( 2 )CO Si(O 3 ) 3 Scheme S1. A possible mechanism of double bonds on KH570 crosslinking with NBR chains.

5 Figure S1. Images of dielectric elastomer before (a) and after (b) sprayed with compliant electrodes.

6 Figure S2. Schematic of electromechanical testing method.

7 Figure S3. TEM micrographs of NBR composites filled with (a) 10 phr TiO 2, (b) 10 phr TiO 2 -(PDA+KH570), (c) 20 phr TiO 2, (d) 20 phr TiO 2 -(PDA+KH570), (e) 30 phr TiO 2, and (f) 30 phr TiO 2 -(PDA+KH570) particles. The morphologies of the NBR composites filled with different contents of TiO 2 and TiO 2 -(PDA+KH570) particles investigated by transmission electron microscopy (TEM) are showed in Figure S3. From Figure S3 (a), Figure S3 (c), and Figure S3 (e), we can find the TiO 2 particles are not uniformly dispersed, with some agglomerations in matrix. However, the composites filled with TiO 2 -(PDA+KH570) particles exhibit significantly improved dispersion with a little agglomerations, even at TiO 2 - (PDA+KH570) content as high as 30 phr.

8 Figure S4. Curing curves of pure NBR and NBR composites filled with different contents of filler. The curing curves of pure NBR and NBR composites filled with different contents of filler are shown in Figure S4. The crosslink density can also be characterized by the difference S between the maximum torque (S max ) and minimum torque (S min ) in the curing curve. The values of S max, S min, and S are summarized in Table S1. From Table S1, we can find S of NBR composites are lower than that of pure NBR, indicating that the crosslinking process was interfered by TiO 2 nanoparticles. In addition, the Mooney viscosity of pure NBR and NBR composites filled with 20 phr TiO 2 particles and 20 phr TiO 2 -(PDA+KH570) particles were also measured and showed in Table S1.

9 Figure S5. (a) Storage modulus and (b) tan δ of 30 phr TiO 2 -(PDA+KH570)/NBR composite as a function of frequency at temperatures 30 o C and100 o C.

10 Figure S6. (a) Temperature dependence of the dielectric constant of the NBR composite filled with different contents of TiO 2 -(PDA+KH570) particles in the temperature range of -80 to 120 o C and (b) frequency dependence of dielectric loss tangent of NBR composite filled with 20 phr TiO 2 -(PDA+KH570) particles in the temperature range of -60 to 100 o C. Figure S6 (a) shows the temperature dependence of the dielectric constant of the NBR composite filled with different contents of TiO 2 -(PDA+KH570) particles in the

11 temperature range of -80 to 120 o C. We can find the maximum dielectric constant of the composite films appeared at 0 o C. The result might be explained as follows. The mobility and thermal expansion of the composites is competing effect on the dielectric constant. 1 When the temperature is increased from -80 to 0 o C, the interfacial interaction restrained the thermal expansion and the formation of interspace. When temperatures greater than 0 o C, the effect of thermal expansion is fully exhibited. However, the difference of coefficient of thermal expansion between NBR and TiO 2 is great that it might overwhelm the effect of polymer mobility on the dielectric constant. As a result, the dielectric constant decreases with increasing temperature at high temperature. The frequency dependence of dielectric loss tangent of NBR composite filled with 20 phr TiO 2 -(PDA+KH570) particles in the temperature range of -60 to 100 o C is showed in Figure S6 (b). From Figure S6 (b), we can find the dielectric loss tangent is more dependent on the frequency at high temperature than that at low temperature. This can be explained as follows. In the high temperature range, the relaxation of polar groups in polymer chains is dominant, whereas in the low temperature range the dielectric response of the NBR composite is determined by the anomaly characteristic of the glass transition of the polymer.

12 Figure S7. Response time of NBR composite filled with 20 phr TiO 2 -(PDA+KH570) particles at 50 kv/mm. Figure S7 shows the response time of NBR composite filled with 20 phr TiO 2 - (PDA+KH570) particles at 50 kv/mm. From Figure S7, we can find the actuator takes 3 seconds to reach a constant value, and it takes 2 s to recover. The speed of response of an actuator depends on two main factors: electric system including the conductivity of the electrodes (they need time to charge and discharge) and viscosity of the elastomer (higher viscosity could result in longer response time).

13 Figure S8. Time dependence of actuated strain of NBR composite filled with 20 phr

14 TiO 2 -(PDA+KH570) particles actuator under an electric field of 20 kv/mm, 30 kv/mm, and 40 kv/mm for 10 cycles. Figure S8 shows the time dependence of actuated strain of NBR composite filled with 20 phr TiO 2 -(PDA+KH570) particles actuator under an electric field of 20 kv/mm, 30 kv/mm, and 40 kv/mm for 10 cycles. Each application period of 10 seconds was followed by an off-interval of 3 seconds. As shown in Figure S8, the actuated strain is relatively stable with time, a desirable feature of TiO 2 - (PDA+KH570)/NBR composite. Reference [1] Z. M. Dang, Y. Q. Lin, H. P. Xu, C. Y. Shi, S. T. Li and J. Bai, Adv. Funct. Mater., 2008, 18, 1509.

NITRILE RUBBER (NBR) NANOCOMPOSITES BASED ON DIFFERENT FILLER GEOMETRIES (Nanocalcium carbonate, Carbon nanotube and Nanoclay)

CHAPTER 5 NITRILE RUBBER (NBR) NANOCOMPOSITES BASED ON DIFFERENT FILLER GEOMETRIES (Nanocalcium carbonate, Carbon nanotube and Nanoclay) 5.1 Introduction Nanocalcium carbonate (NCC) is a particulate nanofiller