Filtration and Breakdown of Clay Clusters during Resin Transfer Molding of Nanoclay/Glass/Epoxy Composites

Dispersion of nanoclay clusters during resin transfer molding of nanoclay/glass/epoxy disks is investigated. In addition to a center-gated disk containing only 14% glass fibers, three nanocomposite disks are fabricated with the addition of 2, 5 or 10 wt% Cloisite® 25A nanoclay. The spatial distribution of nanoclay clusters along the radial axis of the nanocomposite disks are characterized at two length scales. Clusters larger than 1.5 μm are characterized by performing image analysis on the SEM micrographs whereas smaller nanoclay clusters are identified by wavelength dispersive spectrometry. Results obtained from image analysis indicate that nanoclay clusters are filtered out by as much as 50% in the flow direction by the glass fiber preforms. In addition, increasing nanoclay content led to higher filtration, suggesting that cluster formation is more prominent at higher nanoclay loadings. Cluster size distribution analyses revealed that the outer edges of the disks, on average, contain finer nanoclay particles. For instance, the outer edge of the nanocomposite with 2% clay contains 22% more small nanoclay clusters compared to center of the disk. Glass transition temperature, Tg, of four specimens obtained from each molded disks is characterized under oscillatory shear. Glass transition temperature of the samples are shown to increase with the nanoclay content, yielding a 40% higher Tg at 10% nanoclay loading compared to glass/epoxy composite without clay. Increasing glass transition temperature with increasing nanoclay content may be an indication of intercalation of nanoclay within the epoxy matrix.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

MULTISCALE CHARACTERIZATION OF NANOCOMPOSITES FABRICATED BY COPULVERIZATION OF EPOXY RESIN AND NANOCLAY IMECE2005-80380

ABSTRACT INTRODUCTION Effect of nanoclay on the thermo-mechanical properties of BT250E-1 epoxy resin is investigated. Nanocomposite parts containing 0, 2 and 10wt. % of Cloisite ® 30B nanoclay are fabricated by copulverization of nanoclay with epoxy resin at -25°C. Desired amounts of solid epoxy resin and nanoclay are placed into a grinder and copulverized for 20 seconds. The resulting fine powder is then cured using an APA2000 rheometer by using the time-temperature profile provided by the resin supplier. Five disk-shaped parts for each nanoclay content are fabricated. Two rectangular samples are cut out from each disk and used for characterization of mechanical properties and microstructure. Physical properties of polymers can be altered significantly by the addition of particulates. Traditionally, particulates such as calcium carbonate are added to reduce cost at the expense of strength. However, development of nano-scale particulates in the last two decades resulted in materials such as carbon nanotubes and nanoclay, which might improve mechanical performance in addition to other thermo-physical properties. Nanoclay, contrary to carbon nanotubes, is cost effective owing to its abundance in the nature and low processing cost Transmission electron microscopy indicates several nanovoids trapped in the intra-cluster regions. The existence of these voids is also verified by density measurements of the cured samples of the epoxy with and without nanoclay. The reduction observed in the flexural strength is believed to be due to these nanovoids and nanoclay agglomeration. Researchers often achieved promising results when they utilized nanoclay with various thermoplastic resin