Dynamic Compression Induced Solidification
Dynamic Compression Induced Solidification
复制标题
DOI：
10.3390/polym12020488
复制
发表时间：
2020-02-01
期刊：
影响因子：
5
通讯作者：
Drummer, Dietmar
中科院分区：
文献类型：
--
作者：
Roth, Benedikt;Wildner, Wolfgang;Drummer, Dietmar
本研究提出了一种利用高压毛细管流变仪（HPC）测量流动过程中聚碳酸酯（PC）动态压力依赖性凝固的方法。此外，在静态无剪切条件下，通过等温压力-体积-温度（pvT）测量确定了压力依赖性凝固。与压缩速度无关，可以确定凝固压力随温度的线性增加。此外，研究结果表明，在恒定的温度和压缩率下，弛豫时间可以增加到材料不能再遵循压缩率规定的时间尺度的程度。因此，通过毛细管的流动在特定压力下停止，较高的压缩率导致较低的凝固压力。因此，对于HPC测量，可以表明，通过压力孔的压力评估可能导致在极限范围内的测量误差。由于注射成型中的填充过程通常发生在这种瞬态条件下，因此研究结果可能与高纵横比薄壁和微结构的流动过程建模有关。
This study presents a method for the determination of the dynamic pressure-dependent solidification of polycarbonate (PC) during flow using high pressure capillary rheometer (HPC) measurements. In addition, the pressure-dependent solidification was determined by isothermal pressure-volume-temperature (pvT) measurements under static conditions without shear. Independent of the compression velocity, a linear increase of the solidification pressure with temperature could be determined. Furthermore, the results indicate that the relaxation time at a constant temperature and compression rate can increase to such an extent that the material can no longer follow within the time scale specified by the compression rate. Consequently, the flow through the capillary stops at a specific pressure, with higher compression rates resulting in lower solidification pressures. Consequently, in regard to HPC measurements, it could be shown that the evaluation of the pressure via a pressure hole can lead to measurement errors in the limit range. Since the filling process in injection molding usually takes place under such transient conditions, the results are likely to be relevant for modelling the flow processes of thin-walled and microstructures with high aspect ratios.