چكيده لاتين :
The effects of differently tunctionalized polypropylene (PP) and styrene-ethylenebutene-
styrene copolymer (SEBS) on different properties of stretched-extruded
films of PP/EVOH blend were examined. The effect of melt stretching after die was
also studied, The stretched films of the original and polymer-g-diethyl maleate (OEM)
modified blends showed laminar morphology, whereas their maleic anhydride (MA) functionalized
counterparts showed fibrillar morphology. Rheology of the neat polymers along
with their straight and compatibilized blends was studied to assess the quality of mixing
under the actual conditions of blending in a counter-rotating twin-screw extruder to control
and retain laminar morphology. Differential scanning calorimetry (DSC) tests showed
a higher rate of interactions in the case polymer-g-MA modified blends. The SEBS-modified
blends showed a lower elasticity at low temperatures. Mechanical properties were
improved for almost all modified blends. SEM Micrographs revealed that as a result of
melt-stretching post-extruding stretching a finely dispersed EVOH phase in PP matrix
was obtained in the case of polymer-g-MA compatibilizer, whereas a laminar one was
obtained in the case of polymer-g-OEM compatibilizer. The lowest permeability to oxygen
gas was observed for DEM-grafted polymers. The SEBS-g-DEM modified blends showed
a barrier performance 90% better than that of pure matrix (PP) and 60% better than that
of the original stretched blend.
