Four chain extenders, 1,3-propanediol (PDO), 2-methyl-1,3-propanediol (MPO), 2,2-dimethyl-1,3-propanediol (NPG) and 2,2,4,4-tetramethyl-1,3-cyclobutanedio (CBDO) are chosen to synthesize model polyurethanes, respectively. Although with similar oxygen distance between the two hydroxyl groups, their volumes increase gradually according to computer simulation. As expected, the degree of microphase separation decreases with the increasing chain extender volume. Except for CBDO based polyurethane, the other three samples show systematic variations in mechanical properties. Various techniques including single-molecule force spectroscopy (SMFS), small-angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) are employed to investigate the structural changes after tensile break in different length scales. A picture of asynchronous fracture of microstructures during the tensile break of thermoplastic polyurethane elastomers can be obtained by the combination of different analytical methods. It is interesting to note that the macroscopic break may not affect the state of hydrogen bonding or the hard phase network. Sometimes, the hydrogen bonding state changes a lot while the phase network keeps almost the same, or vice versa.

四扩链剂，1,3-丙二醇（PDO），2-甲基-1,3-丙二醇（MPO），2,2-二甲基-1,3-丙二醇（NPG）和2,2,4,4-四甲基选择-1,3-环丁烷二（CBDO）分别合成模型聚氨酯。尽管两个羟基之间的氧距相似，但根据计算机模拟，它们的体积逐渐增加。如预期的那样，随着扩链剂体积的增加，微相分离的程度降低。除了基于CBDO的聚氨酯外，其他三个样品均显示出机械性能的系统变化。包括单分子力谱（SMFS），小角X射线散射（SAXS）和傅立叶变换红外光谱（FTIR）在内的各种技术被用来研究不同长度尺度下拉伸断裂后的结构变化。热塑性聚氨酯弹性体拉伸断裂过程中微观结构的异步断裂图片可以通过组合不同的分析方法获得。有趣的是，宏观断裂可能不会影响氢键或硬相网络的状态。有时，氢键的状态会发生很大变化，而相网络几乎保持不变，反之亦然。