Polymer nanocomposite

About: Polymer nanocomposite is a research topic. Over the lifetime, 8977 publications have been published within this topic receiving 297599 citations.

High-and low-field dielectric characteristics of dielectrophoretically aligned ceramic/polymer nanocomposites

Abstract: Polymer/ceramic composites with controlled spatial distribution of fillers are synthesized, and the corresponding changes in their properties are studied. Using dielectrophoretic assembly, we create anisotropic composites of aligned BaTiO3 particles in silicone elastomer and study their electrical properties as a function of ceramic volume fraction and composite morphology. These structured composites show an increase in the permittivity compared to composites with the same composition and randomly dispersed (0–3) fillers. This study emphasizes the important role of conductivity, permittivity, and, particularly, local cluster distribution in controlling high-field dielectric behavior. Designed anisotropy in dielectric properties can provide unexampled paradigms for the development of high energy density materials and gain important insights into the mechanisms that control dielectric breakdown strengths and nonlinear conduction at high fields in polymer/ceramic composites.

Exfoliation and dispersion enhancement in polypropylene nanocomposites by in‐situ melt phase ultrasonication

Abstract: A novel process using ultrasonics to enhance the exfoliation and dispersion of clay platelets in polypropylene-based nanocomposites has been proposed and investigated. The materials studied were isotactic polypropylene of various molecular weights reinforced with organophilic montmorillonite clay (nanoclay) at 4–6 wt% loadings. X-ray diffraction (XRD) and rheological measurements, on a model system of nanoclay in mineral oil, were first used to determine ultrasonic energy requirements. The effectiveness of the proposed ultrasonic processing technique on polypropylene nanocomposites was evaluated by XRD and transmission electron microscopy (TEM). The effects of added maleic anhydride–grafted polypropylene compatibilizer, polypropylene molecular weight, and pretreatment of the nanoclays on the nanocomposite exfoliation were also investigated. Results indicate that ultrasonic processing of polymer nanocomposites in the melt state is an effective method for improving exfoliation and dispersion of nanoclays. Issues regarding molecular weight degradation, optimization, mechanical properties, and continuous processing are beyond the scope of the present study and are currently being investigated in our laboratory. Polym. Eng. Sci. 44:1773–1782, 2004. © 2004 Society of Plastics Engineers.

Influence of polymer matrix composition and architecture on polymer nanocomposite formation: Coarse-grained molecular dynamics simulation

Abstract: Coarse-grained molecular dynamics simulations of stacks of two-dimensional platelets immersed in a polymer melt were performed to investigate aspects of the polymer matrix that promote the formation of intercalated or exfoliated nanocomposite structures Such factors include temperature, copolymer architecture, and blend composition Increasing the polymer-sheet attractive interaction led to binding of the sheets, where individual beads simultaneously attract two neighboring sheets, thus kinetically blocking intercalation by occupying the perimeter of the affected gallery Polymers with a small polymer-sheet attraction, but having a strongly attractive chain end (end-functionalized polymers) minimized the bonding of adjacent sheets These systems exhibited some sheet sliding because a majority of the confined polymer beads only interacted weakly with adjacent sheets; however, the number density of intercalated polymer was low Mixtures of end-functionalized and nonfunctionalized polymers, however, yielded better intercalation efficiency For the mixed system, the reduced number of highly attractive beads provided sufficient interaction for intercalation to occur, enabling greater intercalation rates, less sheet-bridging, and incorporation of the nonfunctionalized polymers into the galleries © 2003 Wiley Periodicals, Inc J Polym Sci Part B: Polym Phys 41: 3272–3284, 2003

Carbon Nanotubes Composites: Processing, Grafting and Mechanical and Thermal Properties

Abstract: Carbon nanotubes represent one of the most important materials in nanoscience and nanotechnology today. The exceptional properties that these materials possess open new fields in science and engineering. Additionally, the chemistryassociated to these materi- als starts to play an important role, inasmuch, new moieties insert by different chemical routes, inside and outside of carbon nanotubes surfaces, have shown able to modify their structure and properties. To this date, new properties have been found in chemically-modified nanotubes and diverse potential applications are suggested for these materials. One of the most frequent applications for these carbon ma- terials is their inclusion as reinforcement in polymer matrices, due to the amazing structural, mechanical, electrical, chemical and thermal properties that carbon nanotubes possess, suggesting that these materials are ideal to produce new polymer nanocomposites. In this con- text, carbon nanotube nanocomposites have been developed by numerous research groups around the world aiming to produce new novel strong and light composite materials. Also, electrical conductivity and thermal properties have been studied for this kind of nanocompo- sites. However, new challenges to create a new age of multifunctional composite materials with these nanometric forms arise and, there- fore, the study of new properties in these nanocomposites has increased significantly in the last few years. In this review we discuss a range of methods to properly utilize nanotubes in poymer-based composites, from the solubility behavior of carbon nanotubes, the proc- essing methods to develop carbon nanotube polymer composites, interactions produced between carbon nanotubes and polymer grafted, to the most recent results on the mechanical and thermal properties of carbon nanotubes polymer composites, synthesized with different types of carbon nanotubes. In addition, we discuss the effect of different chemical modifications on nanotubes, with special focus on those developed to improve the compatibility between these nanostructures and engineering polymers, as well as their effect on the final composites properties. The significance of understanding, enhancing and controlling the behavior at the interface between nanotubes and polymer matrices towards the development of novel multifunctional applications with these composites, is also discussed in detail.