PA6/POE-g-MAH共混体系缺口冲击断裂机理研究

Study on the notched impact fractured mechanism of PA6/POE-g-MAH blends

研究了PA6/POE-g-MAH共混体系缺口冲击断裂的裂纹萌生、裂纹扩展、冲击断面形貌及紧邻断面下方截面上的相形态。结果显示:随着POE-g-MAH质量分数增加,PA6/POE-g-MAH共混体系缺口冲击断裂发生脆韧转变,裂纹源由"中心辐射型"转变为"线型",裂纹扩展形貌由岩石状脆性断裂特征转变为具有横纹形貌的韧性断裂特征。在紧邻韧性断面下方的截面上可观察到网状形貌,可能是由被刻蚀掉的POE-g-MAH和冲击时基体微观破坏共同组成。在脆性断裂的截面上则无明显的网状形貌。PA6/POE-g-MAH共混体系的断面及截面形貌变化与其脆韧转变的逾渗行为完全对应。DSC分析认为POE-g-MAH提高POE-g-MAH/PA6共混物的缺口冲击韧性与其对PA6晶体结构的改变没有关系。

Crack initiation, crack propagation, impact fracture-surface morphology and section-morphology beyond fracture-surface of PA-6/POE-g-MAH blends in notched impact were studied in this paper. The result shows that brittle-ductile transition of notched impact fracture of PA-6/POE-g-MAH blends occurs with POE-g-MAH weight fraction increasing, crack origin transforms from ＂the type of center radiation＂ to ＂the type of line＂, crack propagation transforms from brittle patch fracture morphology to ductile cross-veins morphology. Net morphologies below fracture surface may be consisted of micro-damage zones of matrix and etched POE-g-MAH. There is not clear net in the section of brittle fracture. The changes of fracture surface and section morphologies of PA- 6/POE-g-MAH blends in notched impact are corresponding to its percolation behavior of brittle-ductile transition It is concluded that the good impact ductile of PA-6/POE-g-MAH blends hasn＇t been related to its crystal structure variation by DSC analysis.