Effect of Nanoclay Content on Void Morphology in Resin Transfer Molded Composites

Abstract

Effects of nanoclay content on morphology and spatial distribution of voids in resin transfer molded nanoclay/E-glass/epoxy composite disks are investigated. Closite Õ 25A nanoclay loads of 2, 5, and 10 wt% are mixed by sonication with a low-viscosity epoxy resin prior to filling the mold cavity containing 13.6% E-glass preform by volume. A disk without nanoclay is also molded. Once the molded composites are cured, voids on radial composite samples are evaluated via microscopic image analysis. The addition of nanoclay is found to result in a significant increase in the apparent viscosity of the clay-epoxy mixture, thus increasing the molding pressure. Void occurrence is observed to increase considerably with increasing nanoclay content, from 2.1% in the composite without nanoclay to 5.1 and 8.3% in the composites molded with 5 and 10 wt% nanoclay, respectively. However, the composite with 2 wt% nanoclay yields the lowest void content of 0.7%. Voids are observed to be, in average, smaller after the addition of nanoclay at all nanoclay concentrations. Presence of nanoclay in the impregnating resin induces at least 60% reduction in voids located inside fiber tows, which are trapped by the fluid front motion during impregnation. Irregularly shaped voids are also observed to decrease with increasing nanoclay content. A nonuniform void content and morphology is observed radially, which seems to be affected by the flow kinematics as well as possible breakdown and filtration of clay clusters.

Effect of organoclay platelets on the mechanical properties of wood–plastic composites formulated with virgin and recycled polypropylene

“…Such nanoscale fillers frequently exhibit large surface-to-volume ratios and improve properties such as gas permeability resistance, fire resistance and dimensional stability of the fabricated composites (Cho & Paul, 2001;Zhao et al, 2005;Mohan et al, 2007;Hamidi et al, 2008;Zhang et al, 2009).…”

Manufacture and properties of a structural synthetic polymer fiber-containing nanoclay for concrete reinforcement

“…In some cases, only 1-5% nanoparticle content is needed to match selected properties of a microcomposite containing 20-40% filler [9,[12][13][14]. However, when the nanoparticles are not distributed evenly, agglomeration of the nanoparticles can occur and improvement in material properties may not be realized.…”

Effect of fiber treatment and nanoclay on the tensile properties of jute fiber reinforced polyethylene/clay nanocomposites

“…As a result, the tensile strength and modulus are found to be improved. Addition of nanoclay adversely affects the final properties of the composite but at high concentration of clay, nanoclay poorly dispersed inside the matrix forming platelet agglomerations which act as stress concentrators which in turn cause reduction in mechanical properties of the composite [37]. Thus, poor dispersion of more than 2 wt% of nanoclay is thought to lead to poor interface which will result in poor mechanical properties.…”