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Impact of processing history on rheological properties for branched polypropylene
- Source :
-
Polymer . May2006, Vol. 47 Issue 10, p3629-3635. 7p. - Publication Year :
- 2006
-
Abstract
- Abstract: The impact of applied processing history and the post-processing annealing procedure on the rheological properties of long-chain branched polypropylene (B-PP) have been studied intensively as compared with conventional linear polypropylene (L-PP) and low-density polyethylene (LDPE) produced by autoclave process. It was found that drawdown force, as a measure of melt elasticity for B-PP, is greatly depressed even by the short-time processing in an internal batch mixer, whereas the rheological properties of L-PP are unchanged by the processing history. Considering that the drawdown force is recovered to the original value during the post-processing annealing, the phenomenon is ascribed to the conformation change related to the branch structure, i.e. the alignment of long branches to a backbone chain, which is known as ‘shear modification’. Further, it is demonstrated that the depression of the drawdown force for B-PP is more significant than that for LDPE. Moreover, it is also clarified that B-PP needs a longer post-processing annealing time to recover the drawdown force than LDPE. The difference in the recovery curves during the annealing suggests that B-PP has less relatively ‘short’ long branches. [Copyright &y& Elsevier]
- Subjects :
- *RHEOLOGY
*POLYPROPYLENE
*AUTOCLAVES
*LOW density polyethylene
*THERMOPLASTICS
Subjects
Details
- Language :
- English
- ISSN :
- 00323861
- Volume :
- 47
- Issue :
- 10
- Database :
- Academic Search Index
- Journal :
- Polymer
- Publication Type :
- Academic Journal
- Accession number :
- 20732580
- Full Text :
- https://doi.org/10.1016/j.polymer.2006.03.052