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Crystalline memory on polycarbonate
Author(s) -
Filippo Giuseppe V. Di,
González María E.,
Gasiba María T.,
Müller Alejandro V.
Publication year - 1987
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/app.1987.070340514
Subject(s) - crystallinity , polycarbonate , crystallization , materials science , amorphous solid , acetone , extrusion , polymer , atmospheric temperature range , polymer chemistry , crystal (programming language) , chemical engineering , composite material , chemistry , crystallography , organic chemistry , thermodynamics , programming language , physics , computer science , engineering
A significant reduction on the time for thermal crystallization of Bisphenol‐A polycarbonate has been achieved by means of a previous crystallization step of the polymer in acetone, followed by a capillary extrusion processing at temperatures above its melting range (230–280°C). The crystallinity of PC was corroborated qualitatively by means of WAXS and quantitatively by means of DSC. The acetone‐crystallized polymer showed higher values of dynamic viscosity than its amorphous counterpart. Such difference decreased with the increase of the test temperature and disappeared at 280°C. The degree of crystallinity of thermally crystallized PC increased with the decrease of the capillary extrusion temperature of the acetone‐crystallized material. It is inferred that the time–temperature‐dependent long range molecular diffusion necessary for the total melting of the crystal fractions could not take place entirely for the short times employed (≈ 4 min), allowing the extruded polymer to behave as a self‐nucleated material.