【摘要】 以结晶型聚酰胺46(PA46)注塑样条制件为研究对象,采用X射线衍射和差示扫描量热分析了注塑制件不同位置的表层和芯层的结晶行为,使用Moldflow软件对PA46注塑样条制件的剪切速率、结晶过程和尺寸收缩进行了模拟仿真,并与实际注塑成型制件进行比较。在注塑成型的剪切诱导下,PA46在受限区域显示出复杂的结晶行为,其表芯层显示完全不同的晶型结构,且不同位置处的结晶行为也存在很大差异。模拟结果表明,不同位置处的剪切速率和表/芯层的剪切速率梯度对相对结晶度和晶粒尺寸有着直接的影响。基于结晶模拟的PA46注塑制件体积收缩率和沿流动方向的收缩率明显较高,但在厚度和宽度方向上收缩率降低,且小于实测收缩率。通过注塑成型中PA46结晶行为的实验和模拟研究,有助于理解结晶型聚合物在成型过程中的结构演变,实现材料-成型-性能的一体化控制。更多还原

【Abstract】 Taking the injection molding of crystalline polyamide 46(PA46)strip as the research object,the surface and core layer crystallization behavior of the injection molded part at different positions was analyzed by X-ray diffraction and differential scanning calorimetry.The simulation of the injection molded PA46 part was carried out by Moldflow software.The shear rate,crystallization process and dimensional shrinkage of the strips were simulated and compared with actual injection molded parts.Under the shear induction of injection molding,PA46 showed complex crystallization behavior in the restricted area,the surface layer showed completely different crystal structure,and the crystallization behavior at different positions also varied greatly.The simulation results show that the shear rate at different positions and the surface-core layer shear rate gradient have a direct influence on the relative crystallinity and grain size.The volume shrinkage of the PA46 injection molded part based on crystallization simulation and the shrinkage along the flow direction are significantly higher,but the shrinkage rate is reduced in the thickness and width directions,and is smaller than the measured shrinkage ratio.Experimental and simulation studies on the crystallization behavior of PA46 in injection molding are helpful to understand the structural evolution of crystalline polymers during the molding process and to achieve integrated control of material-forming-performance.更多还原