1. a Department of Polymer Science and Engineering , Pusan National University , Pusan, 609-735, Republic of Korea
2. b Technical Center, BASF Company, Limited , Ulsan, 680-180, Republic of Korea
3. c Technical Center, BASF Company, Ltd. , 472-1 Sanggae-Dong, Ulsan, 680-180, Republic of Korea
4. d Department of Chemistry , University of Ulsan , Ulsan, 680-749, Republic of Korea