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Effect of β-crystals on the mechanical and electrical properties of β-nucleated isotactic polypropylene

Effect of β-crystals on the mechanical and electrical properties of β-nucleated isotactic polypropylene
Effect of β-crystals on the mechanical and electrical properties of β-nucleated isotactic polypropylene

Polypropylene has great potential as a thermoplastic insulation material for high voltage direct current (HVDC) cable. However, its mechanical properties restrict its application, particularly at low temperature. In this paper, isotactic polypropylene (iPP) with the β-nucleating agent WBG was prepared by the melt blending method. The crystallinity, β-crystal proportion and crystalline morphology were analyzed by wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and polarized optical microscopy. The results showed that the crystallinity and β-crystal proportion increased as the WBG concentration increased. Three types of β-crystal morphology, namely β-spherulite, flower-like agglomerate and β-quasi-spherulite, were sequentially obtained with increasing WBG concentration. The mechanical properties, space charge distribution, thermally stimulated discharge current and DC electrical breakdown strength were investigated. Compared with pure iPP, the Izod impact strength and DC breakdown strength of iPP/0.1%WBG were improved by 238 and 16%, respectively, and the fracture energy and brittleness temperature of iPP/0.3%WBG were improved by 420 and 80%, respectively. In addition, the space charge accumulation was suppressed in the range of 0.1-0.5 wt% WBG. Chain coupling between the β-crystals and the amorphous phase, particularly in the flower-like agglomerates, was considered to play an important role in improving the mechanical and electrical performance.

DC electrical property, mechanical property, polypropylene, β-crystal
1070-9878
714-721
Zhang, Wei
ec951eab-b3d8-4d03-a424-400745e29448
Xu, Man
21ac4b05-749a-468e-a5b0-71999463e731
Huang, Kaiwen
8402f488-75f6-4fc7-95b3-0f4c169ec445
Mu, Qiulin
f65f4836-78c5-439f-a245-93257eedbcf9
Chen, George
3de45a9c-6c9a-4bcb-90c3-d7e26be21819
Zhang, Wei
ec951eab-b3d8-4d03-a424-400745e29448
Xu, Man
21ac4b05-749a-468e-a5b0-71999463e731
Huang, Kaiwen
8402f488-75f6-4fc7-95b3-0f4c169ec445
Mu, Qiulin
f65f4836-78c5-439f-a245-93257eedbcf9
Chen, George
3de45a9c-6c9a-4bcb-90c3-d7e26be21819

Zhang, Wei, Xu, Man, Huang, Kaiwen, Mu, Qiulin and Chen, George (2019) Effect of β-crystals on the mechanical and electrical properties of β-nucleated isotactic polypropylene. IEEE Transactions on Dielectrics & Electrical Insulation, 26 (3), 714-721, [8726016]. (doi:10.1109/TDEI.2019.8726016).

Record type: Article

Abstract

Polypropylene has great potential as a thermoplastic insulation material for high voltage direct current (HVDC) cable. However, its mechanical properties restrict its application, particularly at low temperature. In this paper, isotactic polypropylene (iPP) with the β-nucleating agent WBG was prepared by the melt blending method. The crystallinity, β-crystal proportion and crystalline morphology were analyzed by wide-angle X-ray diffraction, differential scanning calorimetry, scanning electron microscopy and polarized optical microscopy. The results showed that the crystallinity and β-crystal proportion increased as the WBG concentration increased. Three types of β-crystal morphology, namely β-spherulite, flower-like agglomerate and β-quasi-spherulite, were sequentially obtained with increasing WBG concentration. The mechanical properties, space charge distribution, thermally stimulated discharge current and DC electrical breakdown strength were investigated. Compared with pure iPP, the Izod impact strength and DC breakdown strength of iPP/0.1%WBG were improved by 238 and 16%, respectively, and the fracture energy and brittleness temperature of iPP/0.3%WBG were improved by 420 and 80%, respectively. In addition, the space charge accumulation was suppressed in the range of 0.1-0.5 wt% WBG. Chain coupling between the β-crystals and the amorphous phase, particularly in the flower-like agglomerates, was considered to play an important role in improving the mechanical and electrical performance.

Text
7632-Effect of β-Crystals on the Mechanical and Electrical Properties of β-Nucleated Isotactic Polypropylene-0813 - Accepted Manuscript
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More information

Accepted/In Press date: 9 October 2018
e-pub ahead of print date: 29 May 2019
Published date: 1 June 2019
Keywords: DC electrical property, mechanical property, polypropylene, β-crystal

Identifiers

Local EPrints ID: 432087
URI: http://eprints.soton.ac.uk/id/eprint/432087
ISSN: 1070-9878
PURE UUID: 33662275-f347-4072-8c23-bc96b276e541

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Date deposited: 01 Jul 2019 16:30
Last modified: 19 Jul 2019 16:32

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