Effect of SWCNT Dispersion on Epoxy Nanocomposite Properties

C. UZUNPINAR; M. A. MOSIEWICKI; M. L. AUAD

POLYMER COMPOSITES

JOHN WILEY & SONS INC

Año: 2012 vol. 33 p. 582 - 588

0272-8397

In nanocomposites containing single wall carbon nanotubes (SWCNTs), the final properties strongly depend on the dispersion quality of these fillers. Various methods have been used to improve the dispersion of nanofillers; however, one of the most effective ways is to functionalize carbon nanotubes with covalent and non-covalent functional groups. In this work, the dispersion of SWCNTs in an epoxy system was studied by using surfactants, acid (COOH) and ester groups (PGE) modified carbon nanotubes. Rheological and SEM analysis showed that functionalization of carbon nanotubes helped in improving the dispersion of fillers in the epoxy matrix. Systems with surfactant modified SWCNTs (1 wt%) exhibited the highest storage modulus at low frequencies after 5 min. sonication. This behavior is associated to a stronger network of fillers as a result of a good dispersion. However, longer sonication times lowered the storage modulus, corresponding to a degradation of the tubes. The effect of the dispersion quality on mechanical properties was also studied using a 3-point bending set-up. Incorporation of acidified SWCNTs improved the flexural modulus by 19%, while adding surfactant assisted SWCNTs with 5 min. sonication enhanced the flexural modulus by 48%.