| Author Name | Affiliation | | Yongzhe Li | College of Mechanical Engineering, Henan University of Technology, Zhengzhou 450001, China | | Haihong Wu | College of Mechanical Engineering, Henan University of Technology, Zhengzhou 450001, China | | Ziyue Guo | School of Mathematics, Sun Yat-sen University, Zhuhai 519082,Guangdong, China | | Chuntai Liu | National Engineering Research Centre for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China |
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| Abstract: |
| Due to the strong shearing field during processing, untra-thin injection molded CNT-filled polypropylene (PP) always forms a strong CNT orientation along the flow direction, which results in its anisotropic conductivity. In order to evaluate the mechanism on recovery of the orientation, we processed the molding under the condition of different thermal compressive strains with modified hot-rolling machine. The stability of the molding's conductivity after rolling was studied under the action of alternated loading. The disoriented behavior of the microstructures during rolling was observed by SEM and 2D-WAXD, and the degree of orientation of CNT was calculated. The conductivity of the sample was measured using a standard two-terminal DC resistor. The results showed that the deformation resistance in the rolling direction was greater than that in the transverse deformation under the action of large thermal compressive strain. The samples would mainly deform in the transverse direction and not elongate in the direction of the rolling, which could speed up the recovery of the orientation structure and reduce the anisotropy of the conductivity. The recovery speed of the orientation was related to the level of the thermal compressive strain. After the hot-rolling processing, the stability of the sample's conductivity under the alternating load was improved because of the effect induced by polymer strengthening. |
| Key words: ultra-thin injection molding Nanocomposites orientation recovery conductive stability |
| DOI：10.11916/j.issn.1005-9113.17100 |
| Clc Number:TH14 |
| Fund: |
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| Descriptions in Chinese: |
| 热压应变对超薄CNT填充的聚丙烯成型取向度回复的影响 李永喆1，吴海宏1，郭子月2，刘春太3，申长雨3 （1. 河南工业大学 机电工程学院，郑州 450001；2.中山大学 数学学院（珠海），珠海 519082；3.郑州大学 橡塑模具国家工程研究中心，郑州 450002） 创新点说明：1）超薄注塑成型方式，由于其壁厚小，流动剪切应力大，表面厚度方向从表面到内芯的明显取向结构，这增加了机械性能的各向异性，特别是纳米复合材料的成型。超薄注射成型的CNT填充聚丙烯（PP）总是沿着流动方向形成强的CNT取向，导致各向异性导电。 2）利用改性热压机加工成型，在大的热应力作用下，轧制方向的变形阻力大于横向变形。样品主要在横向上变形，而不是在轧制方向上延伸。 研究目的： 用改性热压机在不同热压应变条件下加工成型，在交变载荷作用下，这样可改善加速取向结构的回复并可降低导电性的各向异性。 研究方法： 将配置好的CNT-PP添加到设置好温度的转速双螺杆挤出机料斗，让成型后的制品在改进的辊压机中轧制成型。然后通过SEM和2D-WAXD观察轧制过程中微观组织的散乱方向；用公式计算CNT的取向度；使用标准的两端直流电阻测量样品的电导率。 结果： 超薄注塑后的CNT-PP经改进的滚压机滚压后导电趋于各向同性，导电稳定性更加良好；经SEM观察后取向结构得到改善。 结论： 在交替载荷作用下，轧制变形过程增加了CNT填充的PP复合材料的力学性能的稳定性，并改善了导电性能。 关键词：超薄注塑成型；纳米复合材料；取向度回复；导电稳定性 |
