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Khonakdar, H. A. ; Jafari, S.H. ; Haghighi Als, A. ; Wagenknecht, U. ; Häußler, L. ; Reuter, U.
Thermal and mechanical properties of uncrosslinked and chemically crosslinked polyethylene/ethylene vinyl acetate copolymer blends

Uncrosslinked and chemically crosslinked binary blends of low- and high-density polyethylene (PE), with ethylene vinyl acetate copolymer (EVA), were prepared by a melt-mixing process using 0-3 wt % tert-butyl cumyl peroxide (BCUP). The uncrosslinked blends revealed two distinct unchanged melting peaks corresponding to the individual components of the blends, but with a reduced overall degree of crystallinity. The crosslinking further reduced crystallinity, but enhanced compatibility between EVA and polyethylene, with LDPE being more compatible than HDPE. Blended with 20 wt % EVA, the EVA melting peak was almost disappeared after the addition of BCUP, and only the corresponding PE melting point was observed at a lowered temperature. But blended with 40% EVA, two peaks still existed with a slight shift toward lower temperatures. Changes of mechanical properties with blending ratio, crosslinking, and temperature had been dominated by the extent of crystallinity, crosslinking degree, and morphology of the blend. A good correlation was observed between elongation-at-break and morphological properties. The blends with higher level of compatibility showed less deviation from the additive rule of mixtures. The deviation became more pronounced for HDPE/EVA blends in the phase inversion region, while an opposite trend was observed for LDPE/EVA blends with co-continuous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3261-3270, 2007

Journal of Applied Polymer Science 103



March 2007


Nanostructured Materials