Polyethylene-Based Single Polymer Composites Prepared under Elongational Flow for High-Voltage Applications
2020
Huang, Zhao-Xia | Zhao, Ming-Liang | Qu, Jin-Ping
Recently, polyethylene (PE)-based single polymer composites (SPCs) have been found to be potential candidates for high-voltage applications (HVAs) due to their ability to form supramolecular structures and their recyclabilities. However, a deeper understanding of the controls and evolutions of such a structure is still needed. Herein, by introducing elongational flow into the melt compounding, we could successfully control the structure of polymeric materials and prepared PE-SPCs with additive-level ultrahigh-molecular-weight polyethylene (UHMWPE) for HVAs. The elongational flow-induced multiscale multilevel structure was confirmed and analyzed through X-ray diffraction. Specifically, under elongational flow, we fabricated PE-SPCs with the shish-kebab structure and 2D variated crystal units. The melting behaviors of each sample were studied, and the results indicated an elongational flow-induced cocrystallization phenomenon of low-density polyethylene and UHMWPE during melt processing. Benefiting from the as-formed structure, we obtained PE-SPCs with enhanced mechanical properties and more HVA-adaptable dielectric properties. Particularly, the yield strength, tensile strength, and Young’s modulus of PE-SPC (sample R80) show 42, 23, and 29% enhancement than the virgin PE, respectively. The dielectric constant and dielectric loss of our PE-SPC are determined to be around 2.94 and 2 × 10–⁴ at 1000 Hz, respectively. Moreover, 10-fold decreases in conductivites in both AC and DC of our PE-SPC are achieved after melt compounding under elongational flow. In conclusion, this work gives a comprehensive understanding of the PE-SPCs’ structure evolution under elongational flow, and the structure–property relationship was also determined. It is believed that this work can promote the development of SPCs for HVAs.
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