Special Issue "Nanocomposites of Polymers and Inorganic Particles 2011"

Guest Editor
Dr. Laïla Raki
Concrete Materials and Structural Technologies, Institute for Research in Construction, National Research Council Canada, 1200 Montreal Road, M-20, Ottawa, ON, K1A 0R6, Canada
Website: http://www.nrc-cnrc.gc.ca/irc-irc/index.html
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Phone: +1 613 9912612
Fax: +1 613 9545984

Guest Editor
Prof. Dr. Claudio Nicolini
Nanoworld Institute – CIRSDNNOB and Biophysics Division, University of Genova, Corso Europa 30, 16132 Genoa, Italy
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Dear Colleagues,

In recent years, polymer-nanoparticle composites have attracted the interest of a number of researchers, mainly because of their hybrid properties derived from different components. In the materials industry, the development of polymer nanocomposites is rapidly expanding as a multidisciplinary research activity and is gaining momentum in mainstream commercial applications. The mixing of polymers, including biopolymers and inorganic matrices, and nanoparticles is opening new routes for engineering flexible composites that exhibit unique electrical, optical, mechanical or thermal characteristics. These novel materials benefit from the synergy between nanoparticles (filler) and polymers (matrix) to tailor nanocomposite materials with new and enhanced properties. So far, commonly used fillers are inorganic particles with spherical or layered materials such as metals (e.g. silver), semiconductors (e.g. CdS) or clay minerals (e.g. montmorillonite). However, nanofibers (e.g nanotubes) also show the promise to be used as fillers. Recent advances reveal new promising pathways to tailor the single components (matrix and filler) and thereby control the macroscopic performance of the composite material. As a result, several sustainable and eco-efficient applications have been identified for these novel materials including automotive and aerospace industry as well as in construction, electrical/electronics applications and food packing.

Prof. Dr. Claudio Nicolini
Dr. Laïla Raki
Guest Editors

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• nanoparticles
• nanotubes
• polymers
• composites
• sustainability
• eco-efficient

Title: Coating of Carbon Fiber with POSS to Enhance Mechanical Properties and Durability of Carbon/Vinyl Ester Composites
Authors: Hassan Mahfuz¹, Felicia Powell ¹, Richard Granata ¹ and Mahesh Hosur ²
Affiliations: ¹ Florida Atlantic University, Boca Raton, Florida; E-Mail: hmahfuz@fau.edu (H.M.)
² Tuskegee University, Tuskegee, AL 36088, USA
Abstract: Our continuing quest to improve performance of polymer composites under moist and salt water environment has gained momentum in recent years with the reinforcement of inorganic nanoparticles into the polymer. The key to mitigate the degradation of composites under such environment is to maintain the integrity of the fiber/matrix (F/M) interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by coating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS). POSS is a nanostructured inorganic-organic hybrid particle with a cubic structure having eight silicon atoms at the core and linked to 12 oxygen atoms. The advantage of using POSS is that the silicon atoms can be linked to a substituent that can be almost any chemical group known in organic chemistry. Cubic silica cores are ‘hard particles’ and are about 0.53 nm in diameter. The peripheral organic unit is a sphere of about 1-3 nm diameter. In a composite, these hard particles are linked to an organic component with known architecture. Therefore, a nanocomposite with completely defined interfacial component between the carbon fiber and the vinyl ester matrix can be obtained. Further, cubic structure of POSS remains intact during the polymerization process and therefore POSS particles with appropriate functional groups, if installed on the fiber surface, would provide a stable and strong F/M interface. Two POSS systems with two different functional groups; namely, OctaIsobutyl and Trisilanolphenyl have been investigated. A set of chemical and mechanical procedures has been developed to coat carbon fibers with POSS, and fabricate layered composites with vinyl ester resin. Interlaminar shear, transverse tension, and low velocity impact tests have indicated around 20% improvement in mechanical properties with respect to control samples made without the POSS coating. Differential scanning calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) tests have also shown significant improvement in glass transition temperature (T_g). Salt water and hygrothermal tests at various environmental conditions have revealed that coating with POSS reduces water absorption by 20-30% and retains the composite properties achieved under dry conditions.