采用恒速型双毛细管流变仪研究高密度聚乙烯(PE-HD)与乙烯-醋酸乙烯共聚物(EVA)共混物的流变现象,着重研究了不同比例 EVA 的加入对 PE-HD 的黏度及压力振荡现象的改善情况。研究发现,在 PE-HD 中添加适量的 EVA 可以降低共混物的黏度,在低剪切速率下,共混物的黏度对 EVA 的用量比较敏感,随着 EVA 用量的增加呈近似线性减小趋势;在 PE-HD 中添加适量的 EVA 可以抑制压力振荡现象,使共混物发生振荡的临界剪切速率升高,振荡的振幅减小。
Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-shaped mold cavity in steady state,the filling time,the distribution of velocity field and the pressure field were obtained.The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process.Through the comparison,it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate,while it can be neglected in other situations such as calculating the distribution of the velocity fields.This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future.
