Study on the definition, mechanism and controllability of secondary bubbles based on the bubble nucleation model in injection foaming polypropylene.

The process of nucleation and growth of polypropylene foam was observed by using visualizations of the mold-opening foam injection molding (MOFIM) and free foaming (FREEF). The fitting of the mathematical model formula was used to supplement the judgment conditions of the secondary bubbles to explore the generation process and formation conditions of the secondary bubbles. The results of changes in blowing agent content and melt temperature proved the rationality of the judgment basis and the appearance of secondary bubbles started from the late stage of balanced-foaming.

Rheological behavior, crystallization properties, and foaming performance of chain-extended poly (lactic acid) by functionalized epoxy.

The inherently linear poly (lactic acid) suffers unsatisfying foaming behavior due to its low melt strength and poor crystallization properties. To overcome this drawback, a random terpolymer of ethylene, acrylic ester and glycidyl methacrylate (EGMA) was employed to improve the rheological behavior, crystallization properties, and foaming performance of poly (lactic acid) (PLA) through a chain extension reaction. The branched/micro-crosslinked structure formed by the chain extension reaction between EGMA and PLA effectively improved the dynamic rheological properties of PLA.

In-Situ Visualization of the Cell Formation Process of Foamed Polypropylene under Different Foaming Environments.

In this paper, the dynamic foaming process of micro-foaming polypropylene (PP) in different foaming environments in real time was obtained via a visualization device. The relationship curve between cell number () and foaming time () was plotted, and then the nucleation kinetics of foam cells was analyzed. Results showed that the formation rate of cells changed obviously with the variation of melt temperature and the content of the foaming agent.

Effect of early external X-ray radiation on arterial restenosis post percutaneous transluminal angioplasty.

Background: Arterial restenosis after percutaneous transluminal angioplasty (PTA) significantly reduces its therapeutic efficacy in treating lower extremity atherosclerotic occlusive diseases (LEAOD). Early external X-ray external radiation has demonstrated positive effects on restenosis; however, effective dosing and the mechanism(s) underlying its efficacy remain unknown. This study explored the effect of early external X-ray radiation on preventing post-PTA restenosis in an iliac intimal injury model.

The effect of early external X-ray radiation on arterial restenosis post percutaneous transluminal angioplasty.

Background: Arterial restenosis after percutaneous transluminal angioplasty (PTA) significantly reduces its therapeutic efficacy in treating lower extremity atherosclerotic occlusive diseases (LEAOD). Early external X-ray external radiation has demonstrated positive effects on restenosis; however, effective dosing and the mechanism(s) underlying its efficacy remain unknown. This study explored the effect of early external X-ray radiation on preventing post-PTA restenosis in an iliac intimal injury model.