US EPA

4423429 

Journal Article 

Ionic conductivity of cross-linked polymethacrylate derivatives/cyclophosphazenes/Li+ salt complexes 

Inoue, K; Yamauchi, T; Itoh, T; Ihara, E 

2007 

Yes 

Journal of Inorganic and Organometallic Polymers and Materials
ISSN: 1574-1443
EISSN: 1574-1451 

17 

2 

367-375 

10.1007/s10904-007-9126-3 

WOS:000246111400005 

The role of cyclophosphazenes with oxyethylene chains (N3P3(OCH2CH2)(n)OCH3, (n = 3, 3, n = 7.2, 4) and N4P4[OC6H4O(CH2CH2O)(7.2)CH3](8) (8) for the synthesis and ionic conductivity in polymethacrylate networks was studied. Reflecting the structural features of cyclophosphazenes, the Li-7 NMR spectra of the mixture of 3 and LiN(SO2CF3)(2) showed that more than 40% of the Li+ salt could exist as a free ion at room temperature. Similar values were obtained for 4 and 8. Cross-linked methacrylate polymers (12-14, and 16-18) were prepared from the reaction of poly(ethylene glycol) methyl ether methacrylate and poly(ethylene glycol) dimethacrylate both in the presence of these cyclophosphazenes which act as molecular imprinting molecules (method II, M-II) and without the cyclophosphazene (method I) DSC studies of the imprinted polymer, 12(20)/3/Li+ system after removal of the cyclophosphazene showed that the glass transition temperature range (Delta T-g) becomes significantly narrower compared to that of the unimprinted 11(20)/3/Li+ system, where cross-linked polymer 11(20) was prepared in the absence of the cyclophosphazenes (method I, M-I). The ionic conductivity of the Li+/cross-linked polymer system was improved by the subsequent readdition of the cyclophosphazenes. The 12(20)/3/Li+ complex showed a conductivity of 1.1 x 10(-3) S/cm at 90 degrees C, which was two times higher than that of the 11(20)/3/Li+ complex. The effectiveness of the small molecule imprinting technique for the preparation of cross-linked polyelectrolytes with high conductivity and mechanical stability is discussed. 

cyclophosphazene; polyelectrolyte; conductivity; cross-linked polymer