聚乙烯拉伸断裂统计行为与分子链取向方向的关系OA

As polyethylene(PE)crystallizes from the melt,a large number of defects occur alongside the formation of crystal structures in the system.In order to reveal the influence of these defects on the fracture behavior of PE,the statistical fracture behavior of blown polyethylene film stretched at room temperature was studied.The statistical fracture behavior(fracture strain,fracture stress and fracture energy)of 100 tensile bars in each stretching direction was investigated by stretching the blown PE film along different directions(0,45 and 90(°))with respect to the original blowing direction.It was found that the statistical fracture behaviour of the sample oriented along the original blowing direction conforms fully to a Gaussian distribution.This indicates that fracture is dominated by defects.However,the statistical fracture behavior of samples stretched at 45 and 90(°)deviates slightly from Gaussian distribution,suggesting that defects distribution in these two samples differs from that of 0(°)sample.Additionally,samples stretched along 45 and 90(°)have relatively high average fracture strain,stress,and energy values compared to samples deformed along 0(°).This reflects the reduction in defects in the former two systems,which improves the PE tensile properties.Since defects in the 45 and 90(°)samples can be effectively eliminated,the defect distribution in these systems is no longer uniform.This causes the statistical fracture behaviour to deviate from a Gaussian distribution.This study provides new insights into improving the mechanical properties of polyethylene under large deformation.