聚甲醛流变性能及其纺丝性研究

Study on rheological behavior and spinning property of polyformaldehyde

利用熔融指数仪测、毛细管流变仪测定了聚甲醛在不同熔融温度、时间下的流变性能,由此,为研究聚甲醛的融法纺丝提供理论依据。结果显示:聚甲醛在所测定环境下的流变性质属于假塑性流体,熔融指数(MI)值都随着温度的升高有所增大;在低剪切速率下,POM熔体的黏度值对温度敏感性高,剪切速率大于1000s-1,POM熔体黏度值变化对温度依赖性减弱;此外,提高剪切速率可以较大范围地降低POM熔体的粘流活化能;熔融时间对熔体流变性没有明显的影响,同时通过熔融挤出,确定纺丝温度在210℃为宜。

Abstract The rheological behavior of polyformaldehyde （POM）under different temperature and melting time were measured by melt indexer and capillary rheometer. The results showed that the rheological behavior of POM belong to pseudoplastic fluid, the MI value got higher with increased the temperature. The sensitiveness of viscosity and temperature shown strong in lower shearing rate, when the shearing rate greater than 1000 s^-1 , the sensitiveness got weaker. On the other hand,improving shearing rate made activation energy reduced in large extend. The melting time did not had apparent effect for melt liquidity and 210℃ was defined as the optimum spinning temperature by melt extrusion.