Chemical reactions affecting halloysite dispersion in epoxy nanocomposites

Abstract

Halloysite nanotubes (HNTs) have attracted a technologic and scientific attention as reinforcements of epoxy-based nanocomposites. 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 with different chain lengths and functionality numbers. Evidence of homopolymerization and degradation reactions was found, depending on the surface treatment. The rheological study indicated that an interconnected network can be achieved in epoxy/HNTs blends depending on the surface chemical characteristics of the nanofillers and the blending method. The better dispersion was accomplished when ultrasonicating with the aid of a solvent. Nevertheless, the mechanical properties of the nanocomposites are not warranted by selecting a dispersion method.During the last decade, scientists and engineers have discovered and developed a large range of exciting new applications for these unique, cheap, and abundantly available naturally occurring clays. 17,18 Regarding the production of reinforced polymers, one key factor needed to obtain a composite material that successfully fulfill the required service life performance, is to control nanofiller dispersion and nanofiller/matrix interaction. Due to their lower number of surface hydroxyl groups, it is expected that HNTs will disperse better than other silicates such as montmorillonite and kaolinite. It is reported that HNTs can be dispersed quite uniformly by a direct melt-blending Additional Supporting Information may be found in the online version of this article.

Fluorinated‐polyhedral oligomeric silsesquioxane (F‐POSS) functionalized halloysite nanotubes (HNTs) as an antifouling additive for epoxy resin

“…A detailed description of the chemical characterization of the nanoclays can be found in a previous work. 44 The fluorinated modifier used to functionalize the surface of HNT was 1H,1H,2H,2H perfluorooctyltriethoxysilane (PFOTES, Worldyachem Co., China). Other reactants and solvents employed in surface and bulk modifications were TEOS (Merk, Buenos Aires), ammonia 28 wt.% and anhydrous ethanol (Biopack, Buenos Aires).…”

“…Such a wide range of degradation temperature is almost well-known for the silane chains degradation. 44…”

“…Some agglomerates of smaller size, which have already been partially detached from the matrix, can also be found, characteristic of the pattern of agglomerates' pull up and population of the holes. 44 F I G U R E 1 1 Scanning electron microscopy images of free surfaces (A) epoxy; (B, C) E-F-POSS@HNT-5; and (D, E) E-F-POSS@HNT-10.…”

Влияние Нанотрубок Галлуазита На Микрорастрескивание Матрицы В Эпоксидных Углепластиках

“…Тщательный обзор литературы показал, что улучшен ная межповерхностная адгезия между галлуазитом и эпоксидной смо лой -многообещающий способ достижения эффективного улучшения механических свойств всех композиций. Модификация поверхности и прививка ГНТ аминосиланами, а также гибридные нанонаполнители (ГНТ и УНТ) предложены для создания эффективной передачи нагрузки между матрицей и арматурой [42,54]. Дальнейшие исследования в этой области могут улучшить армирующую способность эпоксидной матрицы при малом содержании ГНТ.…”

Preparation of HNTs‐e‐POSS hybrid nanoparticles and modification of gallic acid epoxy resin

“…The shell composed of polyphosphazene (PZM) effectively promotes the interfacial interaction between HNTs and epoxy resin matrix. S anchez M et al 27 modified the surface of HNTs by alkali treatment and grafting of two different structures of amino silanes. The results showed that a chemical bond network could be formed between epoxy resin and HNTs.…”