Polymers with extraordinarily broad glass transition regions and utility as broad-T-range damping materials: Designing nanophase separation with broad interphases in gradient copolymers and segmented polyhydroxyurethanes and thiol-norbornene polymers

摘要

Polymers that exhibit nanophase separation with very broad interphases can exhibit extraordinarly broad glass transtition regions, even exceeding 100 K in breadth. In turn, such materials can also exhibit very broad-temperature-ranging acoustic and vibration damping properties, because good damping characteristics, associated with tan delta > 0.30, often result near the glass transition. Three example systems will be described with can lead to such extraordinary damping characteristics: (1) gradient copolymers which undergo nanophase separation but with a sinusoidal composition profile, (2) segmented polyhydroxyurethanes that undergo nanophase separation but with intermixing because of hydrogen bond formation between hydroxyl groups on the hard segment and ether oxygens present in the soft segment, and (3) segmented thermoplastic synthesized by thiol-ene click chemistry but containing urethane-based norbornene hard segments.