Step Cycle Deformation Processing of Elastomers and Gels Based on Semicrystalline Polyolefin-based Block Copolymers

ORAL

Abstract

Recent catalysts have enabled the synthesis of block copolymers with semicrystalline syndiotactic and isotactic polypropylene endblocks and amorphous ethylene-r-propylene midblocks. In these copolymers, the crystals play the role of physical crosslinks which can deform plastically under stretching. Neat elastomers, gels in mineral oil and gels from which mineral oil has been extracted have been subjected to step cycle tensile tests. The incremental plastic deformation of the crystals has dramatic effects on the true stress versus extension ratio curves. Moreover, small and wide angle X-ray scattering experiments during step cyclic tests revealed the evolution of the microstructure of the crystalline blocks: crystal fibrils and crystals in the fibrils are oriented parallel to the tensile direction at large strains and once the stress has decreased to zero, the fibrils return to being randomly oriented again.

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Authors

  • Fanny Deplace

    UCSB - MC CAM

  • Zhigang Wang

    UCSB - MC CAM

  • Nathaniel Lynd

    UCSB - MC CAM, Department of Chemical Engineering and the Materials Research Laboratory, University of California, Santa Barbara

  • Atsushi Hotta

    UCSB - MC CAM

  • Glenn Fredrickson

    UCSB - MC CAM, Materials Research Laboratory, University of California, Santa Barbara, University of California, Santa Barbara, Materials Research Lab, UCSB, Department of Chemical Engineering and the Materials Research Laboratory, University of California, Santa Barbara, UCSB, USA, UC Santa Barbara, UCSB

  • Ed Kramer

    UCSB - MC CAM, Department of Materials and Chemical Engineering, University of California Santa Barbara, University of California, Santa Barbara, Mitsubishi Chemicals-Center for Advanced Materials, Materials Research Laboratory, University of California, Santa Barbara, CA 93106, UCSB, Materials Research Laboratory, University of California, Santa Barbara, Materials Department, UCSB, University of California Santa Barbara

  • Jeffrey M. Rose

    Cornell University

  • Anna E. Cherian

    Cornell University

  • Geoffrey W. Coates

    Cornell University

  • Hisashi Ohtaki

    Mitsubishi Chemical Group, Science and Technology Research Center

  • K. Hirokane

    Mitsubishi Chemical Group, Science and Technology Research Center

  • F. Yamada

    Mitsubishi Chemical Group, Science and Technology Research Center

  • Yong-Woo Shin

    Mitsubishi Chemical Group, Science and Technology Research Center

  • Fumihiko Shimizu

    Mitsubishi Chemical Group, Science and Technology Research Center