(559d) Morphology and Properties of Nanocomposites from Poly(ethylene-co-methacrylic acid) Ionomers | AIChE

(559d) Morphology and Properties of Nanocomposites from Poly(ethylene-co-methacrylic acid) Ionomers

Authors 

Paul, D. - Presenter, The University of Texas at Austin
Cui, L. - Presenter, The University of Texas at Austin
Shah, R. K. - Presenter, The University of Texas at Austin
Yoo, Y. - Presenter, The University of Texas at Austin


Ionomers, where some of the acid groups of ethylene/methacrylic acid copolymers are neutralized to form sodium, zinc or magnesium salts, offer an attractive option in facilitating the exfoliation of the organoclay in polyolefin type matrices. Besides improving the clarity of the polymer, the acid and ionic groups provide the possibility of favorable interactions with the organoclay. Various structural aspects of an ionomer matrix, such as type of neutralizing ion and degree of neutralization of the acid groups, which could have an effect on its ability to exfoliate the organoclays, are discussed in this study. Along with these, some other efforts were made to find the best organoclay structure for nanocomposites prepared from a given ethylene/methacrylic acid sodium ionomer. Nanocomposites studied here were all prepared by melt processing in a twin-screw extruder, followed by a series of characterizations, such as stress-strain analysis, Izod and Dynatup impact tests, wide angle X-ray scattering (WAXS), and transmission electron microscopy (TEM) coupled with particle analysis, to evaluate the morphology and properties of the nanocomposites. The results suggest that nanocomposites prepared from the sodium and the zinc ionomers displayed much better exfoliation of the organoclay and superior levels of reinforcement compared to equivalent nanocomposites prepared from the lithium ionomer. Improved exfoliation of organoclay with elevated degree of neutralization of acid groups in sodium ionomers were observed, indicating that the sodium ionic units in ionomers provide more favorable interaction between the matrix and organoclay as compared to acid units, and lead to better dispersion of the clay particle.