Chemical reactions affecting halloysite dispersion in epoxy nanocomposites

Abstract

Halloysite nanotubes (HNTs) have attracted a technologic and scientific attention as reinforcements of epoxy-basednanocomposites. However, their reported interaction with epoxy matrices is varied and the controlled dispersion of HNTs is still a challenge. In this work, we study the effect of chemical reactions taking place in the dispersion process of halloysite and their possible influence in the composite?s properties. HNTs? surface was modified through an alkaline treatment and by grafting two aminosilanes withdifferent chain lengths and functionality numbers. Evidence of homopolymerization and degradation reactions was found, dependingon the surface treatment. The rheological study indicated that an interconnected network can be achieved in epoxy/HNTs blendsdepending on the surface chemical characteristics of the nanofillers and the blending method. The better dispersion was accomplishedwhen ultrasonicating with the aid of a solvent. Nevertheless, the mechanical properties of the nanocomposites are not warranted byselecting a dispersion method