In this study, we investigated the effect of carbon black distribution on the degradation of mechanical properties of high-density polyethylene in the form of plastic pipes used in water distribution networks. Polyethylene pipes with similar carbon black concentrations but different carbon black distributions were produced with industrial scale compounding and extrusion equipment. Tensile specimens were directly prepared from extruded pipe samples and elongated to fracture at different strain rates. Carbon black distributions of bulk samples and fracture surfaces were investigated using stereo and scanning electron microscopy (SEM). It was found that the carbon black distributions, fracture surfaces and fracture modes were significantly different in these pipes. Although the yield properties were similar, the post-yield properties of samples were significantly different, dramatically decreasing with the increasing inhomogeneity of carbon black distribution. Pipes with a certain level of heterogeneity in the carbon black distribution showed ductile and brittle fractures in the same fracture plane, whereas homogenous black and natural polyethylene (without carbon black) showed ductile fractures only.

在这项研究中，我们研究了炭黑分布对以水分配管网形式使用的塑料管形式的高密度聚乙烯的机械性能退化的影响。用工业规模的混炼和挤出设备生产出具有相似炭黑浓度但炭黑分布不同的聚乙烯管。拉伸试样直接由挤出的管材样品制备，并以不同的应变速率拉伸至断裂。使用立体和扫描电子显微镜（SEM）研究了大块样品和断裂表面的炭黑分布。结果发现，这些管道的炭黑分布，断裂表面和断裂模式均存在显着差异。尽管产量特性相似，样品的屈服后特性显着不同，随着炭黑分布不均匀性的增加而急剧下降。炭黑分布中具有一定程度异质性的管道在同一断裂面上显示出韧性和脆性断裂，而均质的黑色和天然聚乙烯（无炭黑）仅显示出韧性断裂。