Premium
Influence of thermal treatments, molecular weight, and molecular weight distribution on the crystallization of β‐isotactic polypropylene
Author(s) -
Marigo Antonio,
Marega Carla,
Causin Valerio,
Ferrari Paolo
Publication year - 2003
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.13260
Subject(s) - tacticity , crystallization , differential scanning calorimetry , crystallization of polymers , materials science , lamellar structure , recrystallization (geology) , polypropylene , polymer , molar mass distribution , isothermal process , polymer chemistry , melting point , chemical engineering , thermodynamics , composite material , polymerization , paleontology , physics , biology , engineering
Six samples of isotactic polypropylene were examined to study the influence of the thermal treatments and the molecular weights and their distribution on the β‐crystallization of the polymer. The highest amount of the β‐phase was obtained by isothermal crystallization and in correspondence of high average molecular weights and wide molecular weight distributions. Small‐angle X‐ray scattering pointed out that a partial β‐crystallization seems not to influence the lamellar morphology parameters. Differential scanning calorimetry measurements, at different heating rates, allowed us to confirm that the multiple melting endotherms behavior of the β‐phase is to be correlated to a melting–recrystallization–melting mechanism. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1008–1012, 2004