Surfactant, Compatibilizers and Co-Solvent Assisted CNT-PMMA Composites

5 Surfactant, Compatibilizers and Co-Solvent Assisted CNT-PMMA Composites 

In the majority of the methods discussed above, CNTs are directly mixed with PMMA using ultrasonication or shear forces. Another approach which has been studied to improve quality of dispersion of CNTs in PMMA is third component assisted dispersion of CNTs (65-67). In this method, a third component such as a surfactant or a compatibilizer is added to assist the dispersion of CNTs in a solvent before mixing with the polymer solution (40). This is an effective non-covalent functionalization technique. 

Jin et al. (65) used poly(vinylidene fluoride) (PVDF) as a compatibilizer to assist dispersion of CNTs in PMMA. Multi-walled carbon nanotubes were first coated with PVDF and then melt-blended with PMMA. Poly(vinylidene fluoride) served as an adhesive to improve wetting of CNTs by PMMA and to increase the interfacial adhesion resulting in improved mechanical properties of MWCNT-PMMA composites. 

Kim et al. (66) used poly(3-hexylthiophene) (P3HT)-graft-PMMA as a compatibilizer to prepare MWCNT-PMMA composites by solution blending. The CNT content was varied from 0.01 to 0.1 wt%. The resulting composites showed improved tensile strength and modulus. 

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 

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