Flexural properties nanocomposites

Kalaitzidou, K., Fukushima, H., and Drzal, L. T. (2007], A new compounding method for exfoliated graphite-polypropylene nanocomposites with enhanced flexural properties and lower percolation threshold. Compos. Sci. TechnoL, 10, pp. 2045-2051. 

Table 9.19 Effect of water treatment on flexural properties of clay-epoxy nanocomposites. Reprinted from [47] with permission from Elsevier.

Tensile, impact, and flexural properties Tensile test is the most widely used method to evaluate the mechanical properties of the resultant nanocomposites, accordingly. Young s modulus, tensile strength, and elongation at break are the three main parameters obtained. These vary with the silica content, but the variation trends are different. Furthermore, the impact test is also widely used for mechanical property characterization. 

Sinha Ray et al. [27] reported the detailed measurement of flexural properties of neat PLA and various nanocomposites prepared with organoclay. They conducted flexural property measurements with injection molded samples according to the ASTM D-790 method. There was a significant increase in flexural modulus for nanocomposite prepared with 4 wt% of organoclay when compared to that of neat PLA, followed by a much slower increase with increasing organoclay content, and a maximum of a 50% increase for nanocomposite... 

In parallel, it has also been formd that mechanical properties, flexural properties, heat distortion temperature, and oxygen gas permeability properties can be greatly improved by modifying PLA with organically modified layered silicate (OMLS) nanocomposites [36]. This is the basis of new PLA manufacture developed by Toyota. 

Nanocomposite researchers are generally interested in the tensile properties of final materials, but there are very few reports concerning the flexural properties of neat biodegradable polymer and its nanocomposites with OMLS. Very recently, Sinha Ray et reported the detailed measurement of flexural... 

Tensile and flexural properties of PP, PP blends with PP-g-MA and PP nanocomposites with a 2 1 ratio of PP-g-MA to clay. Reprinted with permission of John Wiley Sons, Inc. from Ton-That, M.T., Perrin-Sarazin, F., Cole, K.C., Bureau, M.N. and Denault, J. Polyolefin nanocomposites formulation and development , Polym. Eng. Sci., 44 (7), 1212-1219 (2004) Copyright 2004, Wiley. 

In several papers the PLA-organically modified layered silicate nanocomposites were studied.All the nanocomposites exhibited dramatic improvement in many properties as compared to those of neat PEA. These improvements include the rate of crystallization, the mechanical and flexural properties, the heat distortion temperature, and the O2 gas permeability, with a simultaneous improvement in biodegradability of neat PLA.° ... 

INFLUENCE OF SURFACE ENERGY ON DISPERSION AND FLEXURAL PROPERTIES OF PS/PHOSPHONIUM ORGANOCLAY NANOCOMPOSITES... 

Nylon-6-clay nanocomposites were also prepared by melt intercalation process [49]. Mechanical and thermal testing revealed that the properties of Nylon-6-clay nanocomposites are superior to Nylon. The tensile strength, flexural strength, and notched Izod impact strength are similar for both melt intercalation and in sim polymerization methods. However, the heat distortion temperature is low (112°C) for melt intercalated Nylon-6-nanocomposite, compared to 152°C for nanocomposite prepared via in situ polymerization [33]. 

Incorporation of monofunctional epoxy POSS into an amine-cured epoxy network increased and broadened the Tg without changing the crosslink density and enhanced the thermal properties. Additionally, it was found that the thermal and thermal-mechanical properties of resultant styrene-POSS vinylester resin nanocomposites were dependent on the percentage of POSS incorporated into the resin [171]. Over a range of POSS incorporations, the Tg of the copolymers changed very little, but the flexural modulus increased with increasing POSS content. 

Chow, W.S., Lok, S.K. Flexural, morphological and thermal properties of polylactic acid/ organo-montmorillonite nanocomposites. Polym. Polym. Compos. 16(4), 263-270 (2008)... 

The epoxy as well as nanocomposite samples kept in water medivun show a reduction in mechanical properties. The water absorption leads to plasticizing effect in the epoxy matrix, resulting in reduction in interfacial strength between the epoxy and reinforcing particles, which reduces flexural strength and modulus (Table 9.19). 

---