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Water absorption effects on the thermal transition and stiffness of ethylene ionomers
Author(s) -
Tachino Hitoshi,
Hara Hisaaki,
Hirasawa Eisaku,
Kutsumizu Shoichi,
Yano Shinichi
Publication year - 1995
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.1995.070550115
Subject(s) - ionomer , differential scanning calorimetry , endotherm , polymer chemistry , materials science , absorption of water , absorption (acoustics) , ionic bonding , methacrylic acid , polyethylene , chemistry , chemical engineering , thermodynamics , composite material , copolymer , polymer , organic chemistry , ion , physics , engineering
Changes in the thermal transition and stiffness of ionomers occuring during aging or water absorption were investigated. Ionomers used in this study are Na, K, Mg, and Zn salts of poly(ethylene‐ co ‐methacrylic acid) (EMAA), whose methacrylic acid unit is 5.4 mol %. It was found that ionomer stiffness is subject to water absorption and the effect differs with the neutralizing cations. Water absorption effects on the thermal transition, measured by differential scanning calorimetry (DSC), indicate that there are no significant changes in the higher‐temperature endotherm assigned to a melting of polyethylene (PE) crystallities. However, the lower‐temperature endotherm, which we attribute to an order‐disorder transition of ionic aggregates ( T i ), exhibits significant changes upon water absorption. The mechanism of the water absorption effects on the thermal transition and stiffness is described. © 1995 John Wiley & Sons, Inc.