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PVT measurement methodology for semicrystalline polymers to simulate injection‐molding process
Author(s) -
Luyé J.F.,
Régnier G.,
Le Bot Ph.,
Delaunay D.,
Fulchiron R.
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/1097-4628(20010110)79:2<302::aid-app120>3.0.co;2-i
Subject(s) - crystallinity , materials science , crystallization of polymers , crystallization , polymer , volume (thermodynamics) , polypropylene , thermodynamics , thermal , molding (decorative) , composite material , polymer chemistry , physics
This article discusses the specific volume‐measurement methods for semicrystalline polymers needed in order to obtain reliable data. Particularly, the effect of the cooling rate is analyzed, taking into account the thermal gradient in a cylindrical sample. Experimental results for a polypropylene form the basis for the study. In a first step our thermal model was validated by comparing the calculated results with the experimental ones for a temperature range higher than the crystallization zone with different cooling rates and by analyzing the stabilization time of the measured specific volume after cessation of the cooling. Secondly, specific‐volume evolutions from 220°C to 50°C for different cooling rates and different pressures were analyzed, revealing that when the data are corrected to eliminate the thermal gradient effect, the transition zone is much narrower than the experimental one. Moreover, the effect of the pressure and the cooling rate on the relative crystallinity function—that is, on the crystallization kinetics—can be more accurately evaluated. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 302–311, 2001