DAMPING AND MECHANICAL PROPERTIES OF POLYURETHANE MATERIALS BASED ON A MIXTURE OF PREPOLYMERS

A method for obtaining polyurethane (PU) materials based on a mixture of prepolymers with different compositions is proposed to extend and specifically control the temperature range of effective damping. The initial polyurethanes include PU-1, which contains prepolymer-1 based on an oligoester with M = 1500 and an aliphatic diisocyanate; and PU-2, which contains prepolymer-2 based on an oligoether with M = 1000 and an aromatic diisocyanate. Additionally, PU compositions based on mixtures of prepolymer-1 and prepolymer-2 in ratios of 70/30, 50/50, and 30/70 wt.% were synthesized. Light microscopy showed that the initial PUs have a homogeneous structure, while the base-mixed prepolymer PU compositions display a distinct heterophase structure. The damping efficiency of the synthesized PU materials was assessed through their viscoelastic properties obtained using the dynamic mechanical analysis (DMA). Specifically, the mechanical loss parameter (tan δ) was used to define the effective damping region as the temperature range where tan δ ≥ 0.3. The initial PUs exhibited effective damping within the temperature ranges of −28 °C to 2 °C for PU-1 and −5 °C to 42 °C for PU-2. The temperature