چكيده لاتين :
Melt strength of polymer is one of the main primaries for the success of fabricating
low-density extrusion foam and thermoforming process. Polypropylene (PP) as a
linear polyolefin has low melt strength for bubble stabilization and sagging.
Large molecules and long chain branches of PP cause higher molecular entanglements
and increase elongational strength of PP melt. In this paper the rheological behaviour,
melt elasticity, mechanical properties, and crystallinity of linear PP blends are studied and
compared with blends containing a long chain branched PP resins. It is found that ternary
blends of linear PP improve the melt elasticity in a certain composition, comparing to
binary blends. Branched PP resins increase molecular entanglements, which it leads to
higher melt elasticity. The results of this study help to understand the effects of chain size
and chain architecture in increasing the melt strength and melt drawability of PP blends.
These are the most important factors for producing low density PP foam and high quality
thermoformed products.
