Molecular simulation research on the micro effect mechanism of interfacial properties of nano SiO2/meta-aramid fiber

Abstract

In this paper, the molecular dynamics simulation was used to research the micro mechanism of nano SiO2 improving the properties of poly-m-phenyleneisophthalamide (MPIA) insulation paper in oil-immersed power transformers. For the first time, the double-layer model, with silica located at the bottom layer and poly-m-phenyleneisophthalamide fibre located at the upper layer, was built in the molecular simulation software. A strong interaction between SiO2 and meta-aramid was observed, and the interaction energy was negative, which indicates that the SiO2 particles and metaaramid fiber have formed a stable interfacial interaction. In the interaction between nano SiO2 and meta-aramid fibers, the dispersion force interaction energy was found to play a leading role in Van Der Waals force. A new hydrogen bonding network has formed between the interface of nano SiO2 and meta-aramid fiber, which is beneficial to the combination of the two. Among these models, the thermal stability and mechanical properties of the modified interface model of (3×3) are the best. The conclusions of this paper will provide a good reference for further research on the modification of nano SiO2 particles to the meta-aramid insulation paper.

The Effect and Associate Mechanism of Nano SiO2 Particles on the Diffusion Behavior of Water in Insulating Oil

“…A model of a cluster made of nano-SiO 2 particles was created using the Materials Studio 5.0 Building Tool software (version) package [18] as shown in Figure 1. After drawing the cluster, hydrogen atoms were added to the unsaturated bonds.…”

Sun radiation and temperature impact at different periods of the year on the photooxidation of polyethylene films

“…Crystallinity increases as well, consequently to the diffusion of the short chain segments towards the existing crystalline lamellae. It is well known that chain scissions are responsible for the loss of mechanical properties, while crystallinity makes the material more brittle and stiffer [15][16], [20].…”

“…Ageing is mainly due to polymer chain degradation, characterized by the oxidation of the macromolecules accompanied by morphological changes [13][14][15]. As such, FTIR spectroscopy can be regarded as a powerful technique to identify the different oxidation products developing during ageing and allowing also to quantify their concentration changes upon time.…”

A new method for testing the interfacial shear properties between rock and early-aged shotcrete

“…It was found that, the samples for direct shear test was quite difficult to be obtained from tunnel site due to rock fractures, shock and vibration during boring, especially for early-aged samples [15]. To assess the interfacial shear properties between rock and early-aged shotcrete, the bond interfaces of the samples should be prepared without being damaged, and making individual samples might be the possible way, like the direct shear tests on rock-concrete interface [16][17][18][19]. Given this comprehension, a new direct shear test method was developed through making individual samples, without coring process after shotcreting.…”