Synthesis and properties of a new-type of millable polyurethane damping material

Millable polyurethane (MPU) has emerged as an exceptional damping material due to its tailorable molecular structure, modulus stability across wide temperature ranges, and tunable damping properties. However, research to date has predominantly focused on regulating the types and ratios of soft/hard segments, while studies on damping performance optimization through sulfur vulcanization remain insufficient. In this work, a 3MPTMG-MPU raw rubber was synthesized using 3-methyltetrahydrofuran/tetrahydrofuran copolymer polyol (3MPTMG), diphenylmethanediisocyanate (MDI) and trimethylolpropanemonoallyl ether (TME). Vulcanized 3MPTMG-MPU damping materials were prepared with varying sulfur contents (0.5-2.5 phr). The material properties were characterized using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and tensile tests. The experimental results demonstrated that reducing the sulfur content from 2.5 phr to 0.5 phr decreased the glass transition temperature (T_g) from -39 ℃ to -51 ℃ and increased the tan δ_Max from 0.82 to 1.02, representing a 24.4% enhancement. This study provides a novel strategy for designing new high-performance MPU damping materials.