关于纳米蒙脱土影响聚己内酰胺结晶行为及流变行为的研究

Study on the Influence of Nano Montmorillonite on the Crystallization Behavior and Rheological Behavior of Polycaprolactam

通过双螺杆挤出机熔融挤出生产有机改性纳米蒙脱土(MMT)增强聚己内酰胺(PA6)。使用差示扫描量热仪开展自成核试验及非等温结晶行为研究,了解纳米MMT含量对PA6结晶行为的影响,结果表明:少量的纳米MMT可以明显提高成核效率和结晶速率,但继续增加纳米MMT会抑制PA6结晶生长,降低结晶速率和结晶度。使用广角X射线衍射仪研究PA6的结晶行为,结果表明:纯PA6同时存在α及γ晶型,添加纳米MMT的PA6发生α-γ晶型转变,证实纳米MMT与PA6的作用可以改变PA6的结晶行为。使用毛细管流变仪分析纳米MMT含量对PA6熔体受剪切时流变行为的影响,结果表明:纳米MMT含量影响PA6熔体的黏度及非牛顿流体特征,尤其是高纳米MMT含量的PA6在不同剪切速率下表现出明显的黏度变化。

Organic modified nano montmorillonite(MMT)reinforced polycaprolactam(PA6)was produced by melt extrusion in a twin-screw extruder.Self-nucleating experiment and non-isothermal crystallization studies involving differential scanning calorimetry were conducted to understand the influence of nano MMT concentration on the kinetic of PA6 crystallization.The results show that small addition level of nano MMT significantly facilitate nucleation efficiency and crystallization rate,but the continuous increase of nano MMT will inhibit the crystallization growth of PA6 and reduce the crystallization rate and crystallinity.The crystallization behavior of PA6 was studied by wide X-ray diffractometer.The results show that pure PA6 exists at the same timeαandγcrystal form,PA6 added with nano MMT occursα-γwhich confirmed that the interaction of nano MMT and PA6 can change the crystallization behavior of PA6.The effect of nano MMT content on the rheological behavior of PA6 melt under shear was analyzed by capillary rheometer.The results show that the nano MMT content affects the viscosity of PA6 melt and the characteristics of non-Newtonian fluid,especially the PA6 with high nano MMT content shows obvious viscosity change at different shear rates.