Structure and Dynamics of Elastomeric Multiblock Terpolymers containing Glassy, Rubbery and Semicrystalline Blocks.
- University of Minnesota
Multiblock copolymers containing glassy poly-(cyclohexylethylene) (C), rubbery poly(ethylene-alt-propylene) (P), and semicrystalline poly(ethylene) (E) were synthesized by sequential anionic polymerization of styrene, isoprene, and buta-diene followed by catalytic hydrogenation. The resulting CECP-CEC (denoted XPX) and CECP (XP) multiblock copolymers each contain 50 vol % of P and equal amounts of C and E. These materials have been studied by dynamic mechanical spectroscopy (DMS), transmission electron microscopy (TEM), small- an wide-angle X-ray scattering (SAXS and WAXS), di!erential scanning calorimetry (DSC), and tensile deformation to characterize the morphology, phase behavior, and mechanical properties. Microphase separation in these compounds is induced by crystallization of Eand/or chemical incompatibility between the three blocks, leading to a new type of morphology which contains continuous region of P and continuous region ofmicrophase-separated X, resulting inmechanically resilientmaterials.Highmolecular weight block copolymers microphase separate with two di!erent length scales associated with segregation between C and E and X and P. These structural features produce a nonclassical scaling relationship for the C!E domain spacing, d ! N0.31, where N is the degree of polymerization of CEC portion. The role of semicrystalline E domains during uniaxial deformation has been exposed withWAXS experiments, which support a two-stepmechanisminvolving recoverable and nonrecoverable deformation to di!erent extents. Strain hardening is observed in double-anchored XPX, but not in single-anchored XP, at large tensile strains.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1034708
- Journal Information:
- Macromolecules, Vol. 44, Issue 20; ISSN 0024-9297
- Country of Publication:
- United States
- Language:
- English
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