摘要
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 2 D-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 hotrolling processing,the stability of the sample's conductivity under the alternating load was improved because of the effect induced by polymer strengthening.
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.
基金
Sponsored by the National Natural Science Foundation of China(Grant Nos.51373048 and U1604253)
作者简介
Corresponding author:Ziyue Guo.E-mail:guozy25@mail.sysu.edu.cn
