Mechanical properties nanocomposites

Key words Carbon-nickel, CNx-nickel, nanocomposites, mechanical properties, structure... 

S. Dutta, N. Karak, J. P. Saikia and B. Konwar, Biocompatible epoxy modified bio-based polyurethane nanocomposites mechanical property, cytotoxicity and biodegradation , Bioresour Technol, 2009,100, 6391-7. 

Keywords Nanodiamonds, carbon nanotubes, graphene, functionalization, polymer nanocomposites, mechanical properties, tribological properties... 

Keywords polyoxymethylene, polyurethane, montmorillonite, nanocomposite, mechanical properties, thermal degradation. 

One can speculate on the improvement of PP-organomontmorillonite nanocomposite mechanical properties without a compatibilizer if an... 

Mechanical properties represent a very important part of polymer materials characteristics, particularly if the talk is about their application as engineering materials. Nevertheless, even if the indicated materials have another functional assignment, mechanical properties remain always-practical application important factor in this case as well. Particulate-filled polymer nanocomposites mechanical properties have a specific features number, which will be considered below. 

PLA/PCL-OMMT nano-composites were prepared effectively using fatty amides as clay modifier. The nano-composites shows increasing mechanical properties and thermal stability (Hoidy et al, 2010c). New biopolymer nano-composites were prepared by treatment of epoxidized soybean oil and palm oil, respectively plasticized PLA modified MMT with fatty nitrogen compounds. The XRD and TEM results confirmed the production of nanocomposites. The novelty of these studies is use of fatty nitrogen compoimds which reduces the dependence on petroleum-based surfactants (Al-Mulla et al., 2011 Al-Mulla et ah, 2011 Al- Mulla et ah, 2010c). 

Diserens, M., Patscheider, J., and Levy, F., "Mechanical Properties and Oxidation Resistance of Nanocomposite TiN-SiN Physical-Vapor-Deposited Thin Films, Surf. Coat. Technol,Vol. 120 Ill, 1999,65. 

The data provided by Toyota Research Group of Japan on polyamide-MMT nanocomposites indicate tensile strength improvements of approximately 40%-50% at 23°C and modulus improvement of about 70% at the same temperature. Heat distortion temperature has been shown to increase from 65°C for the unmodified polyamide to 152°C for the nanoclay-modified material, all the above having been achieved with just a 5% loading of MMT clay. Similar mechanical property improvements were presented for polymethyl methacrylate-clay hybrids [27]. 

This is a nonpolar rubber with very little unsamration. Nanoclays as well as nanotubes have been used to prepare nanocomposites of ethylene-propylene-diene monomer (EPDM) rubber. The work mostly covers the preparation and characterization of these nanocomposites. Different processing conditions, morphology, and mechanical properties have been smdied [61-64]. Acharya et al. [61] have prepared and characterized the EPDM-based organo-nanoclay composites by X-ray diffracto-gram (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy... 

ENGAGE is an ethylene-octene copolymer. Ray and Bhowmick [70] have prepared nanocomposites based on this copolymer. In this study, the nanoclay was modified in situ by polymerization of acrylate monomer inside the gallery gap of nanoclay. ENGAGE was then intercalated inside the increased gallery gap of the modified nanoclay. The nanocomposites prepared by this method have improved mechanical properties compared to that of the conventional counterparts. Preparation and properties of organically modified nanoclay and its nanocomposites with ethylene-octene copolymer were reported by Maiti et al. [71]. Excellent improvement in mechanical properties and storage modulus was noticed by the workers. The results were explained with the help of morphology, dispersion of the nanofiller, and its interaction with the mbber. 

FIGURE 2.10 Variation in mechanical properties with styrene content in styrene-butadiene rubber (SBR)-based nanocomposites. 

Higher extent of silica generation with high TEOS concentration improves the mechanical properties severalfolds as illustrated by the tensile stress-strain plots on ACM-sdica hybrid nanocomposites on increasing TEOS concentrations in Figure 3.6. 

Different characteristics of solvents seriously affect the sol-gel reaction in solution. This in turn influences the physico-mechanical properties of the resultant rubber-silica hybrid composites. Bandyopadhyay et al. [34,35] have carried out extensive research on stmcture-property correlation in sol-gel-derived rubber-sihca hybrid nanocomposites in different solvents with both chemically interactive (ENR) and noninteractive (ACM) mbber matrices. Figure 3.12 demonstrates the morphology of representative ACM-sihca and ENR-sihca hybrid composites prepared from various solvents. In all the instances, the concentration of TEOS (45 wt%), TEOS/H2O mole ratio (1 2), pH (1.5), and the gelling temperature (ambient condition) were kept unchanged. 

Finer dispersion of silica in THF provides higher surface area to interact with the rubber molecules and the resultant nanocomposites show better mechanical properties than their macrocounterparts. Figure 3.13 illustrates these results. 

Adsorption of rubber over the nanosilica particles alters the viscoelastic responses. Analysis of dynamic mechanical properties therefore provides a direct clue of the mbber-silica interaction. Figure 3.22 shows the variation in storage modulus (log scale) and tan 8 against temperature for ACM-silica, ENR-silica, and in situ acrylic copolymer and terpolymer-silica hybrid nanocomposites. 

Dynamic mechanical properties of the nanocomposites are shown in Figure 4.6. There is 10% improvement of the storage modulus at 20°C by incorporating only 4 wt% of the nanombe. 

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