Premium
Effect of negative pressure on melting behavior of spherulites in thin films of several crystalline polymers
Author(s) -
Pawlak Andrzej,
Piorkowska Ewa
Publication year - 1999
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/(sici)1097-4628(19991107)74:6<1380::aid-app9>3.0.co;2-m
Subject(s) - tacticity , materials science , polymer , ethylene oxide , supercooling , crystallization , melting point , adipate , polymer chemistry , polypropylene , oxide , isothermal process , composite material , chemical engineering , thermodynamics , polymerization , copolymer , metallurgy , engineering , physics
The melting behavior of spherulites in thin films of isotactic polypropylene, poly(ethylene oxide), poly(methylene oxide), and poly(ethylene adipate) crystallized isothermally at various temperatures has been studied by polarized light microscopy. The local increase of melting temperature in regions surrounding cavities and multiple boundary points, dependent on the crystallization temperature, was observed in all studied polymers. In pockets of occluded melt an arising negative pressure lowers an equilibrium melting temperature; hence, decreases an undercooling, which results in the increase of lamellae thickness and their melting temperature. The elevation of melting temperature and the negative pressure buildup depend on the polymer and the crystallization temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1380–1385, 1999