DIELECTRIC-RELAXATION STUDIES ON WATER-ABSORPTION OF ETHYLENE IONOMERS

被引:36
作者
YANO, S
TADANO, K
NAGAO, N
KUTSUMIZU, S
TACHINO, H
HIRASAWA, E
机构
[1] GIFU COLL MED TECHNOL,GIFU 50132,JAPAN
[2] DUPONT MITSUI POLYCHEM CO,CTR TECH,CHIKUSA KU,CHIHARA,CHIBA 29901,JAPAN
关键词
D O I
10.1021/ma00052a015
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Sodium and zinc salts of ethylene-methacrylic acid (5.4 mol %) copolymer were studied by dielectric spectroscopy to clarify how water molecules are absorbed in these ionomers. The samples are denoted EMAA-xNa(or Zn)-yH2O, where x and y are degree of neutralization and molar ratio of H2O to COONa, respectively. The dielectric relaxations of EMAA and EMAA-0.6Zn, whose water absorption is usually small, were scarcely affected by water uptake. On the other hand, the dielectric relaxations of EMAA-xNa, particularly highly neutralized sodium salts, sensitively responded to water uptake. In EMAA-0.90Na-yH2O, for example, a water peak appeared near 270 K at 1 kHz in addition to the alpha and beta relaxations and gradually increased with increasing water content (y). Interestingly, the dielectric increment (DELTAepsilon) of this water peak increased more than 100-fold when y was increased from 2 to 3. At y = 3, a new peak appeared near 320 K and was independent of measuring frequency. The temperature exhibiting this peak corresponded to the order-disorder transition of ionic clusters. These results indicate that three water molecules per sodium cation form a primary hydration shell and that the excess water molecules are absorbed around that shell. Consequently, we can conclude that the ionic clusters are probably transformed into a structure reminiscent of an inverse micelle upon water absorption.
引用
收藏
页码:7168 / 7171
页数:4
相关论文
共 24 条
[1]   Dispersion and absorption in dielectrics I. Alternating current characteristics [J].
Cole, KS ;
Cole, RH .
JOURNAL OF CHEMICAL PHYSICS, 1941, 9 (04) :341-351
[2]   MODEL FOR THE CLUSTERING OF MULTIPLETS IN IONOMERS [J].
DREYFUS, B .
MACROMOLECULES, 1985, 18 (02) :284-292
[3]  
EISENBERG A, 1982, ACS S SERIES, V180
[4]  
EISENBERG A, 1977, ION CONTAINING POLYM, V2
[5]  
ESCOUBES M, 1987, NATO ASI SER C-MATH, V198, P341
[6]  
GIRKE TD, 1981, J POLYM SCI PE, V19, P1687
[7]  
HIRASAWA E, 1990, INT S FINE CHEM FUNC, P102
[8]   SMALL-ANGLE X-RAY-SCATTERING STUDY FOR STRUCTURAL-CHANGES OF THE ION CLUSTER IN A ZINC SALT OF AN ETHYLENE METHACRYLIC-ACID IONOMER ON WATER-ABSORPTION [J].
ISHIOKA, T ;
KOBAYASHI, M .
MACROMOLECULES, 1990, 23 (12) :3183-3186
[9]   SORPTION AND PERMEATION BEHAVIOR OF WATER-VAPOR AND CARBON-DIOXIDE GAS THROUGH ETHYLENE IONOMER MEMBRANES [J].
ITOH, K ;
TSUJITA, Y ;
TAKIZAWA, A ;
KINOSHITA, T .
JOURNAL OF APPLIED POLYMER SCIENCE, 1986, 32 (01) :3335-3343