Simultaneous improvement in strength, toughness, and thermal stability of epoxy/halloysite nanotubes composites by interfacial modification

Abstract

This work investigated the effect of silane modification of halloysite nanotubes (HNTs) on the mechanical properties of epoxy/HNTs nanocomposites. Three kinds of silane coupling agents, including 3-(2-aminoethyl)-aminopropyltrimethoxysilane (AEAPS), (3-glycidyloxypropyl)-trimethoxysilane (GPTMS), and octyltriethoxysilane (OTES), were employed. It was shown that the modified HNTs exhibited a better dispersion in the epoxy matrix compared with pristine one. Because of strong interfacial interaction between AEAPS modified HNTs and the epoxy matrix, the nanocomposites exhibited the highest glass transition temperature and modulus among all the samples. On the other hand, AEAPS and GPTMS modified HNTs/epoxy nanocomposites showed enhanced tensile strength and toughness. The toughing mechanisms were identified by the SEM micrographs of the fracture surfaces of the different kinds of samples. In this study, simultaneous enhancement of strength, toughness, and thermal stability of epoxy by the modified HNTs provides a novel approach to produce high-performance thermosets.

Preparation of viscoelastic gel‐like halloysite hybrids and their application in halloysite/polystyrene composites

“…(A). The characteristic peaks of p‐HNTs at 3694 and 3621 cm −1 , 1083 and 1031 cm −1 , 1114 and 796 cm −1 corresponding to inner‐surface Al&bond;OH stretching bands, in‐plane Si&bond;O stretching, apical Si&bond;O stretching and Si&bond;O&bond;Si symmetric stretching, respectively, are also observed in the spectra of h‐HNTs, indicating that surface treatment with different NaOH concentrations has no effect on the peak position and intensity of bands. Furthermore, it is hard to detect the obvious variation of hydroxyl content using different NaOH solution treatment in the FTIR spectra due to structural complexity of HNTs.…”

“…firstly use piranha solution (a mixture of H 2 SO 4 and H 2 O 2 ) to hydroxylate most of the surface of HNTs, which had higher activity for silanization . Wang and co‐workers further found that silane modification of hydroxylated HNTs firstly treated with NaOH solution could obviously improve the mechanical strength and toughness simultaneously . However, previous studies of surface‐hydroxylated HNTs had only emphasized the use of NaOH solution treatment to increase the hydroxyl content.…”

The use of colemanite and ulexite as novel fillers in epoxy composites: Influences on thermal and physico-mechanical properties

“…Polymer composites compose of filler and polymer matrix like thermoplastic, thermoset and elastomer [7]. Epoxy resins (ERs) are one of the most important thermoset matrices due to their remarkable properties including good mechanical and electrical strength [8], excellent adhesion capacity, high thermal and chemical resistance, low shrinkage [9] and processability [10]. In spite of these advantages, ERs have some adverse properties such as low thermal conductivity [11], high flammability [12] and brittleness [13] that restrict their applications.…”

Chemical reactions affecting halloysite dispersion in epoxy nanocomposites

“…Epoxy resins are types of widely used thermosetting polymers because of their high strength and stiffness, excellent chemical and thermal resistance; however, they are intrinsically fragile which limits their use. Inorganic nanofillers are often employed to improve the toughness of epoxy resin since these fillers can increase the toughness without sacrificing its rigidity and thermal properties . When chosen as matrix for glass and carbon fibers composites due to its excellent suitability for various processing techniques, the intrinsic brittleness of the matrix has greatly restricted their applications .…”

“…Many efforts have been made in order to improve the nanodispersion of HNT expecting an improvement in the matrix toughening. On the one hand, different mixing methods have been reported, like mechanical agitation, ball milling, ultrasonic treatments, solvent assistance, and so forth. On the other hand, there are strategies oriented to improve the filler–matrix physicochemical interaction through the surface modification of the halloysite .…”