聚乙烯/炭黑复合材料电熔焊接研究

Electrofusion welding of polyethylene/carbon black composites

通过熔融共混法在聚乙烯中加炭黑,模拟制备管道用聚乙烯/炭黑复合材料。采用了不同的焊接条件包括单程序焊接和多程序焊接进行复合材料的焊接,并对焊接性能、焊接管道的力学性能、结晶性能、微观形态进行了研究。结果表明,复合材料的制备工艺流程中挤出机的加工温度应避免超过240℃以上,且螺杆转速不超过40 r/min时能够有效避免管道制备过程产生炭黑分散不均匀以及气泡的缺陷;焊接过程中,单段式程序焊接过程中会出现实验末期温度急剧上升的情况,而多段式焊接程序能够使熔区温度保持在一个相对稳定的温度区间,对焊接试样进行拉伸剥离实验可知,多段式焊接程序的焊接性能要优于单段式焊接程序。

In this study,the polyethylene/carbon black composites for pipelines were prepared through melt blending car⁃bon black with polyethylene.The resultant welding composites were further used to weld pipelines under different weld⁃ing conditions including single⁃program welding and multi⁃program welding,and the welding properties,mechanical properties,crystallization properties,and microscopic morphology of the welded pipes were studied.The results indicat⁃ed that the processing temperature of the extruder should not exceed 240℃,and the screw speed should not exceed 40 rpm.This can effectively avoid the defects of uneven dispersion of carbon black and bubble in the preparation process of pipeline.In the single⁃stage welding process,the temperature was found to rise sharply at the end of the experiment.However,the temperature of the melting zone could keep in a relatively stable range in the multi⁃stage welding proce⁃dure.The tensile stripping test results indicated that the welding performance of welded samples obtained from the multi⁃stage welding process was better than that from the single⁃stage welding process.