Calorimetry of nanophase-separated poly(oligoamide-alt-oligoether)s

The miscibility, crystallization, vitrification, and melting behavior of mu ltiblock copolymers consisting of alternating components of oligo[imino(1-o xodo-decamethylene)] and oligo(oxytetramethylene) were investigated in thei r dependence of composition and molecular mass of the blocks. In all compos itions studied, the copolymers present two separate glass transitions at te mperatures not far from those of the corresponding homopolymers. The immisc ible components are linked by chemical bonds to nanophase-separated layers. In such a situation, the structure and mobility of each phase affect the o ther, causing small shifts of the glass-transition temperatures. The enthal py-based crystallinity was calculated separately for each component, using the known information on heat capacities and latent heats. The crystallinit y is influenced by the block lengths. The oligoamide segments crystallize f rom an isotropic melt with a relatively high crystallinity, whereas the oli goether blocks solidify in the presence of crystals and glass of the second component in the adjacent solid nanophases, which greatly reduces their ov erall long-range chain mobility, and as a consequence, their crystallinity is rather small. (C) 2001 John Wiley & Sons, Inc.