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By using treatments such as varying moisture content, densification and chemical treatments etc., samples of yellow poplar (Liriodendron tulipifera) and hard maple (Acer spp.) with different moduli have been studied with Dynamic Mechanical Analysis (DMA) and Solid State I3 C CP/MAS NMR. A correlation between the cross-polarization time constant * and the dynamic storage modulus (E') is established for dry wood. It indicates that <ΤαΡ>* and E' both correspond to similar near static molecular motions in wood. It has also been found that the relationship between <Ύ&Ρ>* and E' is not valid for wet wood samples. Molecular motions of each wood component were analyzed.

The 0.1 mol•L −1 MgSO 4 liquor and 5 mol•L −1 NaOH liquor were prepared by MgSO 4 ·5H 2 O and NaOH as raw materials, and then different diameter nano-Mg(OH) 2 powders were prepared by chemical precipitation. The DTA-TG curves data obtained was by SDT 2960 simultaneous DSC-TGA analysis apparatus. The mensuration conditions were that rise temperature velocity was 15 • C·min −1 , gas was air. The kinetics was calculated by DTA-TG curves data and dα dt = k(1−α) n kinetics model. The results shown that nano-Mg(OH) 2 powders shape were stick or spherical, their diameter were 7, 12, 20, 40, 70 nm. Their thermal decomposition reaction apparent activation energies were 188. 065, 195.935,202.493, 210.178, 297.527KJ·mol −1 , the apparent activation energy increase with Mg(OH) 2 diameter. Their frequency factors were 2.721 × 10 15 , 9.246 × 10 15 , 4.251 × 10 16 , 6.067 × 10 16 , 3.866 × 10 23 , the frequency factors increase with diameter Mg(OH) 2 . Their reaction progression were 0.8296, 0.9321, 0.8743, 1.0275, 0.8903, the reaction progressions were fluctuated in 0.9108 (average) about.