TY - JOUR
T1 - Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of stabilizers
AU - Scaffaro, Roberto
AU - La Mantia, Francesco Paolo
AU - Dintcheva, Nadka Tzankova
AU - Botta, Luigi
AU - Mariani, null
AU - Morreale, Marco
PY - 2009
Y1 - 2009
N2 - Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing speed, and lower initial molecular weight), branching appears still the predominant reaction, but the chain scission becomes progressively more important. In both cases, no crosslinking occurs. The presence of stabilizers has different effects on the relative extent of branching or chain scission reactions depending on the kind and of the amount of stabilizer and on the processing condition adopted. The correct choice of a stabilizer system will, therefore, depend on the desired final structure.
AB - Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing speed, and lower initial molecular weight), branching appears still the predominant reaction, but the chain scission becomes progressively more important. In both cases, no crosslinking occurs. The presence of stabilizers has different effects on the relative extent of branching or chain scission reactions depending on the kind and of the amount of stabilizer and on the processing condition adopted. The correct choice of a stabilizer system will, therefore, depend on the desired final structure.
KW - degradation
KW - polyethylene
KW - stabilization
KW - degradation
KW - polyethylene
KW - stabilization
UR - http://hdl.handle.net/10447/56203
M3 - Article
VL - 49
SP - 1316
EP - 1325
JO - Polymer Engineering and Science
JF - Polymer Engineering and Science
SN - 0032-3888
ER -