The influence of different processing methods on the nature of the dispersion achieved in the creation of a polyurethane nanocomposite is presented. The nanocomposites were produced using two different types of organically modified montmorillonite clays and a sample of fine particles of silicon nitride as a reference material. Rheological data were used to assess the nature of the dispersion achieved using the different processing methods. The nature of the dispersion produced was characterized using wide-angle X-ray scattering measurements of the finally cured products. Dynamic mechanical thermal analysis was used to investigate the effect of the incorporation of clay platelets into the matrix of the polymer. The high-temperature modulus provides evidence of the interaction between the polymer and the clay platelets; however, surprisingly, the glass transition temperatures of the filled and unfilled materials were almost identical

The preparation and physical properties of a series of nanocomposites based on dispersions of Montmorillonite clays in thermoset epoxy resins are reported. The effects of the variation of the concentration of the clay and the influence of a change of the functionality of the epoxy compounds and the amine curing agent are reported. The effects of the method of dispersion of the clay are studied, and it was found that ultrasound provides an effective aid to dispersion of the clay platelets. In general, the addition of clay platelets leads to an increase in the glass-rubber transition, but in the case of a highly cross-linked system, the reverse effect was observed. The effects observed are discussed in the context of the way in which the chemical structure of the monomers influence the dispersion process and the structure of the final resin system.

The preparation and properties of a series of nanocomposite materials obtained using different organically modified montmorillonite clays with a simple epoxy resin are reported. Dynamic mechanical thermal analysis is used to assess the effect of the incorporation of the clay platelets into the matrix of the polymer. In this system, it is observed that with the well‐dispersed clay system the low temperature modulus increases as would be predicted for a filled polymer system. The high temperature modulus increase is consistent with the premise that the polymer is interacting directly with the clay platelets. The glass transition temperature increases with the loading of the clay in the polymer resins. However, the extent to which enhancement of the physical properties of the composite occurs depends on the nature of the organic modifier. Copyright © 2004 Society of Chemical Industry

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Measurements are reported on the cure and physical properties of an epoxy resin created using a functionalised nanosilica filler. The filled bisphenol A epoxy (Nanopox A410) contained 40 wt% silica nanoparticles and was blended with two bisphenol A resins of molecular weights of 355 and 1075 g mol−1, respectively. Cure was achieved using 3,3‐diaminodiphenylsulfone. The functionality of the mixture containing the epoxy nanoparticles was determined using NMR analysis. Cure times showed a progressive decrease with increasing silica level. Dynamic mechanical thermal analysis showed a decrease in the value of the glass transition temperature (Tg) with increasing silica level. Tg was further studied using differential scanning calorimetry. The ability of the nanosilica to create a stable network structure was demonstrated by the variation of the high‐temperature modulus with silica composition. Thermomechanical analysis carried out below and above Tg showed a progressive decrease in the expansion coefficients with increasing silica level, indicating the effectiveness of the functionalised silica nanoparticles in forming a network. The network formed during cure in the nano‐modified epoxy is unable to undergo the densification possible in the pure resin material and explains the observed lowering of Tg with increasing nanosilica content. Copyright © 2009 Society of Chemical Industry