【Polymer】Softening and hardening of thermal plastic polyurethane blends by water absorbed
作者：Donghua Xu, Fang Liu, Ge Pan, Zhigang Zhao, Xue Yang, Hengchong Shi, Shifang Luan*
關鍵字：Blends，Water，Mechanical property
論文來源：期刊
具體來源：polymer
發表時間：2021年
Abstract：
In this work, the effect of water on the structure and mechanical properties of thermoplastic polyurethane (TPU) blends with different ratios of a high and low hardness TPU composition was explored by experiment and simulation. The decrease of modulus of the TPU blends after immersion in water (softening of TPU), and the interesting increase of modulus of wet samples after losing some free water (hardening of TPU) compared to the dry samples, were observed in this work. By analyzing the change of glass transition temperature, the degree of phase separation of samples after immersion in water, and the types of water and hydrogen bond in samples, the possible mechanism behind the above softening and hardening of wet TPU samples was proposed. The softening and hardening of wet TPU samples were attributed to the change of structure in the interface between hard and soft domains in TPU, which is a combined effect including the plasticization of free water, breakage and/or decreasing the strength of original hydrogen bond by water, and formation of new hydrogen bond (elastic activecross-linking point) by free carbonyl groups in TPU and water etc.