Dielectric Properties of silicon dioxide/wood composite

摘要

In order to make clear the mode of binding between silicon dioxide and wood and dielectric properties of silicon dioxide/wood composite, dielectric relaxation was measured for untreated wood (Cunninghamia lanceolata (Lamb.) Hook) and silicon dioxide/wood composite with different weight percentage gain (WPG). Cole-Cole's circular arc law, distribution spectrum of relaxation time and relation model were applied to the results of relaxation due to motions of methylol groups. The results were as following. The generalized relaxation time and ε_s- ε_∞ decreased with increasing WPG The distribution spectrum of relaxation time became more and more low and broadened with increasing WPG The methylol group in the amorphous region of wood cell wall participated in hydrolysis reaction and condensation reaction caused by tetraethylorthosilicate (TEOS), and there is cross-link between silicon dioxide and wood. The value of apparent activation energy (Δ E) increased for silicon dioxide/composite, and increased with increasing WPG Activation enthalpy (ΔH) and activation entropy (ΔS) increased, while activation free energy (ΔG) decreased with increasing WPG The number of hydroxyl group cut in dielectric relaxation increased with increasing WPG