1. School of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-3909, United States
2. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
3. Dynasol Elastómeros, S.A. de C.V.─Dynasol Group, Altamira, Tamaulipas C.P. 89602, Mexico
4. Physics Department, McGill University, Montreal, Quebec H3A 2T8, Canada