ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
There has been considerable controversy over whether one can extract the primary normal stress difference (N1) for polymer melts from hole pressure (PH) and exit pressure (Pex) data. In this paper values of PH and Pex are obtained for three polymer melts in the same slit-die apparatus under the same operating conditions. It is found that there is a good correlation between values of N1 obtained by means of a cone-and-plate rheometer and those obtained by means of PH data and the Higashitani-Pritchard theory. On the other hand, values of N1 obtained by means of Pex data for polystyrene were two to five times higher than those obtained by means of the cone-and-plate device. For the lower molecular weight low density polyethylene (LDPE) sample, values of Pex were found to be both positive and negative. For the higher molecular weight LDPE sample, values of Pex were found not to increase monotonically with with σw. Hence, it was difficult to obtain unequivocal values of N1 for LDPE.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760260307
