Morphology control of polyoxy‐methylene/thermoplastic polyurethane blends by adjusting their viscosity ratio
Morphology control of polyoxy‐methylene/thermoplastic polyurethane blends by adjusting their viscosity ratio
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DOI：
10.1002/pi.2057
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发表时间：
2006-09
影响因子：
3.2
通讯作者：
Zhengang Cheng;Qi Wang
中科院分区：
文献类型：
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作者：
Zhengang Cheng;Qi Wang
聚甲醛（POM）是一种性能优良的重要塑料。但其较差的冲击强度限制了其应用。理论和实验研究证实，热塑性聚氨酯（TPU）能有效提高POM的缺口冲击强度。本文报道了在加工过程中，通过改变TPU与POM的粘度比（P = ηTPU/ηPOM），使POM/TPU共混物具有良好的形貌，可以进一步提高POM/TPU共混物的缺口冲击强度。实验结果表明：TPU的黏度比POM的黏度对温度更敏感，黏度比P随温度升高而减小；剪切速率范围也很广，当加工温度（Tp）在190℃左右时，P接近于1。因此，POM/TPU共混物的相结构随P的变化而变化，在Tp 190℃时，P > = 1时，TPU的分散相呈现椭球状形态。结果表明，长丝形态赋予POM/TPU（90/10）共混物最高的缺口冲击强度（~ 14 kJ m−2）。版权所有©2006化工学会
Polyoxymethylene (POM) is an important plastic with very good properties. However, its poor impact strength limits its applications. Theoretical and experimental studies have confirmed that thermoplastic polyurethane (TPU) can effectively enhance the notched impact strength of POM. This paper reports that the notched impact strength of POM/TPU blends can be further improved when these blends are endowed with a fine morphology by changing the viscosity ratio of TPU to POM (P = ηTPU/ηPOM) during processing. The experimental results show that the viscosity of TPU is more sensitive to temperature than that of POM, and that the viscosity ratio P decreases with increasing temperature; also for quite a wide range of shear rate, P is close to 1 when the processing temperature (Tp) is around 190 °C. Accordingly, the phase structure of POM/TPU blends changes with P. The dispersed phase of TPU shows ellipsoidal morphology when P > 1 at Tp 190 °C. The results suggest that the filamental morphology endows POM/TPU (90/10) blends with the highest notched impact strength (∼14 kJ m−2). Copyright © 2006 Society of Chemical Industry