Water-Tree Resistant Characteristics of Crosslinker-Modified-SiO(2)/XLPE Nanocomposites

Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO(2)), which are used to develop TMPTA-s-SiO(2)/XLPE nanocomposites with...

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Detalles Bibliográficos
Autores principales: Zhang, Yong-Qi, Wang, Xuan, Yu, Ping-Lan, Sun, Wei-Feng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7998441/
https://www.ncbi.nlm.nih.gov/pubmed/33805708
http://dx.doi.org/10.3390/ma14061398
Descripción
Sumario:Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO(2)), which are used to develop TMPTA-s-SiO(2)/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress–strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO(2) nanofillers, TMPTA-s-SiO(2) nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO(2)/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO(2) surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO(2) nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO(2)/XLPE nanocomposites.