ポリ(オキシプロピレン)トリオ-ル系ポリウレタンの低温転移

概要

論文の詳細を見る
Polyurethane networks were prepared from poly (oxypropylene) triol (PPT-1000, -250, and -6000) and 2, 4-tolylenediisocyanate as a model network. The α-dispersions observed in the dynamic mechanical properties of the polyurethanes were associated with glass transition. The dispersion range of loss modulus in α-dispersion was expanded to a low temperature side by increasing the concentration of polar groups. However, the peak intensity of loss modulus peak was not changed. These results differed from those of diol-cured polyurethanes. Relation between the temperature of loss modulus peak, Tα(E"max), and the concentration of polar groups (mol/g) had linear correlation. Tα(°C)=-71.7+2.7×104 {[Urethane]+3.8[Allophanate]}. The contribution of glycerol concentration as a crosslinking site to Tα(E"max) differed from that of allophanate concentration. The β-dispersion was associated with the motions of hydroxyl-terminated poly (oxypropylene) side chains and/or the motion of crosslinking sites (glycerol units and allophanate units). The γ-dispersion (-130--110°C) was associated with a complex relaxation including the local motion of polyether segments and the rotation of methyl side groups.
日本ゴム協会の論文