We report on the rheological investigation of a nematic block copolymer of an azobenzene methacrylate (MA4) and methyl methacrylate (MMA). Relaxation processes are discussed in terms of chain architecture and viscoelastic response of the polymer. In contrast to analogous random copolymers of MMA and MA4, the present block copolymer did not show validity of the time-temperature superposition (TTS) principle for all material functions. TTS was found to work only for the storage modulus. Rheological steady-state and oscillatory measurements were thus compared in order to obtain further insight into such a peculiar phenomenon.
Linear Viscoelastic Behavior of an Azobenzene Nematic Block Copolymer
ANDREOZZI, LAURA;GIORDANO, MARCO;GALLI, GIANCARLO;
2011-01-01
Abstract
We report on the rheological investigation of a nematic block copolymer of an azobenzene methacrylate (MA4) and methyl methacrylate (MMA). Relaxation processes are discussed in terms of chain architecture and viscoelastic response of the polymer. In contrast to analogous random copolymers of MMA and MA4, the present block copolymer did not show validity of the time-temperature superposition (TTS) principle for all material functions. TTS was found to work only for the storage modulus. Rheological steady-state and oscillatory measurements were thus compared in order to obtain further insight into such a peculiar phenomenon.File in questo prodotto:
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