Evaluation of the Degree of Dispersion of Nanofillers by Mechanical, Rheological, and Permeability Analysis

The aim of this paper is a comparison of the effectiveness of different macrocharacterization techniques for the prediction of the degree of dispersion and intercalation of bidimensional nanofillers in an amorphous thermoplastic matrix. Organically modified montmorillonites (omMMT) were used as bidimensional nanofillers, whereas amorphous polyethylene-terephthalate copolymer (PETg) was used as matrix. Wide angle x-ray diffraction analysis showed no relevant difference between the samples processed at different temperatures, all characterized by a predominantly intercalated structure. On the other hand, transmission electron microscopy (TEM) analysis showed the presence of some degree of exfoliation, as well as the presence of lamellar stacks of different thickness. The aspect ratio of lamellar stacks was estimated by means of rheological, mechanical, and gas permeability analysis. All techniques provided values which are in quite good agreement with TEM analysis. Furthermore, all techniques were able to capture the increase in the lamellar stack aspect ratio with decreasing processing temperature. POLYM. ENG. SCI., 51:1280-1285, 2011. (C) 2011 Society of Plastics Engineers