| Abstract: | Because a blend of limited miscibility level produces high damping characteristics in a composite, copolyurethanes of different molecular structure were synthesized to achieve a desired level of miscibility in PVC. A study of the viscoelastic properties of blends of a 50-to-50 weight ratio of polyurethanes and PVC showed a steady decrease in miscibility on replacement of polyurethanes synthesized from polycaprolactone diols with a molecular weight of 2000, with polyurethanes synthesized by poly(ethylene oxide) diols, up to 80 mol percent, whereupon the polyurethanes became immiscible. The temperature range of damping for a particular polyurethane could be controlled by adjusting the ratio of PVC to the polyurethane. More polyurethane in the blend shifts the damping range toward lower temperature, and vice versa. |
