嵌段聚酯脲氨酯弹性体的结晶形态

CRYSTALLINE MORPHOLOGY OF SEGMENTED POLYESTER POLYURETHANEUREA ELASTOMERS

用宽角X-ray衍射(WAXD)研究了嵌段聚酯脲氨酯(PUU)弹性体在不同退火条件下的结晶行为,用扫描电子显微镜(SEM)研究了这些材料断面上的结晶形态。结果表明:PUU中存在着软、硬段结晶,软段结晶对退火温度较敏感,升高退火温度可以增加软段结晶,改善软、硬段两相分离的程度。从SEM照片上看到;在PUU的断面上存在着球晶、棒晶和无定形的连续相,晶体的尺寸和分布依赖于硬段含量和软段分子量的变化。我们认为晶相和硬段无定形相起着物理交联作用,使材料表现出橡胶状的弹性性质。

Crystalline behavior of segmented polyester polyurethaneurea(PUU) elastomers at different annealing conditions was studied by wide-angle X-ray diffraction(WAXD), and crystalline morphologies of the fracture surface of these materials were investigated by scanning electron microscopy(SEM). The WAXD results showed that the crystallines of the soft and hard segments existed in PUU. The soft segment crystalline was more sensitive to the annealing temperature. Raising the annealing temperature could increase the soft segment crystalline and improve the degree of two phase sepcration of the soft and hard segments. It was seen from SEM micrographs that there were spherulites, rod crystalline and amorphous continuous phase on the fracture surface of PUU. The sizes and the distributions of the crystallines depended on the changes of the hard segment content and the soft segment molecular weight. Tt was believed that the crystalline phase and the hard segment amorphous phase acted as physical cross-linking to make the materials exhibit rubbery clastic properties.