Macromolecular modification of EPDM: Wettability, miscibility, and morphology study

The present investigation deals with studies on wettability, miscibility, a nd morphology of the macromolecularly modified EPDM. Two different maleated EPDM rubbers (grafted rubber) were chosen (0.5 and 1% maleation) for such modification and they were used in various proportions. Wettability of the rubber substrate, as observed from dynamic contact angle measurement, was i mproved using these grafted rubbers. Results of X-ray photoelectron spectro scopy showed an increase in oxygen level with higher levels of grafted rubb er in the blends. Morphology study by transmission electron microscopy show ed a smaller domain size for the blend with higher maleic anhydride content in the grafted rubber. The viscosity versus blend ratio results showed a n egative deviation behavior for blends with 1% grafted rubber, whereas a pos itive negative deviation behavior was observed in blends with 0.5% grafted EPDM. As the strength of interaction increased, the glass transition shifte d to a higher temperature. All blends were heterogeneous, as indicated by d ifferent degrees of dispersion. (C) 2001 John Wiley & Sons, Inc. J Appl Pol ym Sci 80: 2647-2661, 2001.