ULTRASONIC CHARACTERIZATION OF THERMOPLASTIC MULTIBLOCK ELASTOMERS

The propagation of ultrasound waves in thermoplastic multiblock elasto mers was investigated by measurements of the ultrasound velocity and a ttenuation. Three polymer series with amorphous-crystalline structure were studied. The soft-segment material was composed of three differen t oligomers for the three series: poly(1,4-oxypropylene)diol for serie s A, oligo(oxyethylene)diol for series B, and dimerized fatty acid for series C. The hard-segment material was composed of poly(butylene ter ephthalate) (PET). The ultrasound velocity and attenuation of these el astomers with variable hard-segment concentration were investigated as a function of the temperature. The observed relaxation processes were ascribed to the glass transition of the soft phase. The possibility o f a general description of these systems is discussed.