Urethane-diacetylene copolymers

The approach that was adopted [66-69] was to prepare a series of urethane-diacetylene copolymers in which polydiacetylene units are incorporated into segmented copolyurethanes. It was shown in Section 8.1.1 that large strain-induced Raman band shifts can be obtained during the deformation of polydiacetylene single crystal fibers [8-12]. In fact, it is found that the largest shift measured so far (—20cm V% strain) is for the C=C triple bond stretching band of polydiacetylenes (Table 8.1). [Pg.214]

Figve 8.8 Schematic representation of the solid-state topochemical polymerization of the diacetylene-urethane hard s ments (a) linear segmented block copolymer (b) cross-polymerized material (after [67]) [Pg.216]

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