Nanocomposites solvent casting method

Chen et al. (67) reported the use of trifluoroacetic acid (TFA) as a cosolvent with tetrahydrofuran (THF) to improve dispersion and processability of the nanocomposites. They prepared MWCNT-PMMA composite films with varying CNT content by solvent casting method using 10 vol % TFA as a co-solvent with tetrahydrofuran (THF). SEM and optical microscopy revealed a good dispersion of nanotubes in solvent and PMMA. The composites showed low percolation... 

B.K. Kuila and A.K. Nandi, Physical, mechanical and conductivity properties of poly(3-hexylthiophene)-montmorillonite clay nanocomposites produced by the solvent casting method. Macromolecules, 37, 8577-8584 (2004). 

Tang et al fabricated CNCs (4-24% v/v) and epoxy resin-based thermosetting thin film nanocomposites by using solvent casting method followed by curing. CNCs with aspect ratios of 10 and 84 were isolated from cotton and trmicates, respectively. The... 

In the case of PCL/OMLS blends prepared by the solvent casting method, whatever the clay content, was decreased with increasing temperature and a transition was observed at about —60°C. From the figures it is clearly observed that PCL/OMLS hybrids showed a strong increase in compared to neat PCL. On the other hand, the tan S curves showed a large maximum at T = —54°C, which corresponds to the Tg of neat PCL this value was similar to that reported for a crystalline annealed PCL. DMA has also been used to study the temperature dependence G of neat PVA upon nanocomposite formation. Results showed the storage modulus of PVA was remarkably improved after nanocomposite preparation with OMLS. 

In solvent casting or solution mixing, CNTs are first dispersed in a suitable solvent and then mixed with a polymer solution to obtain a suspension of nanotubes in the polymer. The mix is then poured into suitable die molds and the solvent is allowed to evaporate to leave behind nanocomposite film. Solution based methods offer advantages of lower viscosities which facilitate uniform mixing and dispersion. Ultrasonication or magnetic stirring is typically used to separate and disperse CNTs uniformly in different solvents or... 

Solution casting has been widely used as a nanocomposite processing method since solvent intercalation is the simplest way to prepare PLA/clay nanocomposites. But, a solvent where polymer is soluble and nanofillers are highly dispersible is necessary. The preparation of PLA-based nanocomposites by this method normally results in good dispersion of the nanofillers within the polymer matrix, and consequently in enhanced properties, as has successfully been demonstrated by some authors. 

Du, Fischer, and Winey (2003) and Zeng et al. (2010) used both methods in attempts to produce the PMMA/carbon nanotube (CNT) nanocomposites. They found ASP resulted in better CNTs dispersion. Unlike the solvent casting process where nanoparticles may agglomerate during solvent evaporation, in ASP, the rapid precipitation of PMMA-CNTs very effectively lock down the well-dispersed structure. 

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