Agglomeration mechanism and restraint measures of SiO2 nanoparticles in meta-aramid fibers doping modification via molecular dynamics simulations

In this work, the nanoparticle agglomeration process has been studied via molecular dynamics simulations to uncover the agglomeration mechanism. When the nanoparticles were far from each other in an aqueous solution, they mainly diffused because of influence of water molecules. When nanoparticles were close to each other, hydrogen bonds between the nanoparticles actively contributed to their agglomeration. In addition, the agglomeration of nanoparticles was also related to their sizes and concentration. A higher nanoparticle concentration led to an increased probability of nanoparticle contact and easier agglomeration. Smaller nanoparticles could diffuse quickly and aggregate more easily, hence resulting in agglomeration. Additionally, to restrain the agglomeration of silicon dioxide nanoparticles, promote compatibility between the inorganic silicon dioxide nanoparticles and organic polymer meta-aramid fibers, and strengthen the interaction between the two molecules, 3-aminopropyltriethyloxy silane was used for chemical modification of the surface of the nanoparticles. By comparing the interaction energy and hydrogen bond energy between interfaces before and after modification, a grafting density of 502% (1/Å2) was achieved, which was comparatively the best. The results of this work provide a valuable basis for further discussion and improvement of the performance of meta-aramid fiber insulation via doping hybridization with silicon dioxide nanoparticles.