セルロースおよび木材の低温での圧電緩和(<小特集>木質材料小特集)

概要

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In this paper the piezoelectric relaxation of cellulose and wood in a low temperature region was studied in relation to the elastic and dielectric relaxations. The piezoelectric strain constant d=d'-id'', the piezoelectric stress constant e=e'-ie'', the elastic constant c=c'+ic'' and the dielectric constant ε=ε'-iε'' were measured at the frequencies of 100 Hz, 50 Hz and 10 Hz over a temperature range from -130℃ to 0℃. There were observed the piezoelectric, elastic and dielectric relaxations. The activation energies for these relaxations were about 10 kcal/mole. These relaxations were ascribed to methylol rotation in cellulose. Piezoelectric relaxation is often ascribed to the elastic and dielectric relaxations in the noncrystalline phase of the two-phase system in which piezoelectric crystallites are embedded in a nonpiezoelectric matrix phase. The Present observations, however, suggest that the piezoelectric relaxation takes place in the crystalline phase and that the two types of polarization with opposite signs and different relaxation time exist in the crystalline phase.
社団法人日本材料学会の論文
1988-05-15