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Temperature‐dependent Cu 2+ ‐Cu 2+ paired structure in ethylene/methacrylic acid copolymer neutralized with Cu(II). Ionic crystallite disordering and polyethylene crystallite melting
Author(s) -
Yamauchi Jun,
Narita Hidehiro,
Kutsumizu Shoichi,
Yano Shinichi
Publication year - 1995
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1995.021961132
Subject(s) - crystallite , endothermic process , polyethylene , polymer chemistry , materials science , copolymer , ionic bonding , methacrylic acid , polymer , crystallography , chemistry , composite material , ion , organic chemistry , adsorption
Temperature‐dependent ESR spectra of Cu 2+ ‐Cu 2+ pairs in ethylene/methacrylic acid copolymer neutralized with Cu(II) were reexamined in detail. The resonance positions and the linewidths of one of the ESR fine‐structure lines showed thermal distension of the Cu 2+ ‐Cu 2+ distance, and the slopes in the temperature variations changed at the temperature associated with melting of the polymer crystallites. No meaningful anomalies were observed around the temperature at which the preceding endothermic transition takes place. In this transition, the Cu 2+ ‐Cu 2+ pairs seems to enter a disordered state, keeping almost the same paired structure. In contrast to this irreversible order‐disorder transition, the melting process in the most part of the polyethylene crystallite phases starts to impose stress upon the Cu 2+ ‐Cu 2+ pairs, accompanying the slope changes of the ESR parameters. These reversible variations with remarkable thermal hysteresis are compatible with the DSC analyses.