To study the characteristics of gas-assisted co-extrusion (GACE), an experimental system of GACE was established. An PP (2. 0HC)/PP (T300) bi-layer profile with rectangular section was extruded through GACE and traditional co-extrusion respectively. Then, a comparative study was performed in four aspects, including the die swell, encapsulation, output and surface quality of the extrudate. The results indicated that the die swell rate of the GACE extrudate was very close to zero and the encapsulation degree decreased by 60%. Also, it proved that the output of GACE was higher than that of traditional co-extrusion under the same conditions. However, there was no obvious difference in surface quality between the exrudates obtained by GACE and traditional co-extrusion. These results showed that GACE can improve the quality of co-extrusion products remarkably and raise the productivity.%为实验研究气体辅助共挤成型工艺的特性,建立了气辅共挤成型实验系统,通过气辅共挤和传统共挤出矩形截面的聚丙烯PP (2.0HC)/PP (T300)双层型材,在挤出胀大、黏性包围、挤出产量及制品表面质量四4个方面做了对比研究.结果表明,气辅共挤制品的挤出胀大率接近于0,黏性包围程度相比传统共挤减小了60％；在相同生产条件下,气辅共挤出产量高于传统共挤,而气辅共挤制品的表面质量与传统共挤制品无明显差别.研究证明了气体辅助共挤能显著改善共挤制品质量并能提高生产效率.
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