Multiple Shape-Memory Behavior of Polyethylene/Polycyclooctene Blends Cross-Linked by Electron Irradiation



Covalent networks prepared by electron irradiation of binary and ternary blends of linear and/or short-chain branched polyethylenes as well as polycyclooctene (polyoctenamer) demonstrate distinctly developed triple- and partly quadruple shape-memory (SM) behavior after one-step programming. Blends having the morphology with well-segregated phases, where the matrix has the lower melting/switching temperature in comparison to the disperse phases, evince pronounced steps of SM recovery and modulus as well as distinct differential scanning calorimetry-melting peaks. Phase morphology and especially phase separation in networks are noticeably affected by thermal history of blends before cross-linking. All investigated networks show high SM performances with strain fixing and strain recovery ratios of 95–99%.

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