Influence of the main components content of Picea jezoensis on acoustic vibration properties

The main chemical composition content of Picea jezoensis (holocellulose, lignin, and extractive content) was measured using the traditional chemical experiment method, and the vibrational parameters including of dynamic elastic modulus E, specific dynamic elastic modulus E/ρ, acoustic impedance Z(ω) and sound radiation coefficient R, of the spruce samples were measured using the multi-channel fast Fourier transform analyzer. The relationship between the different components and wood acoustic vibration properties were analyzed by simple linear regression analysis and bivariate regression models. The results showed that the holocellulose content significantly affected on the acoustic properties of the wood. The vibrational properties first increase and then decrease with the increase in holocellulose content. The best vibration properties is achieved when the holocellulose content is 62% to 65%. Lower lignin content and benzyl alcohol extractive content are beneficial in improving the acoustic properties of wood.

Chemical and structural analysis of lignocellulosic biomass of Ampelodesmos mauritanicus (diss) and Stipa tenacissima

Chemical composition, anatomical characteristics and cell wall structure of Ampelodesmos mauritanicus (Diss) and Stipa tenacissima (Esparto grass) fibers were analyzed. The results reveal the % (W/W) holocellulose content of Diss and Esparto grass was found to be 54.39 % and 51.8 %, respectively. Esparto grass had the greatest % (W/W) lignin content of 32.2 % while Diss had the last lignin content of 24.95 %. Estimation of %( W/W) extractives contents in Diss and Esparto-grass were observed to be 12.03 % and 13.5 % in that order. According to XRD data, Diss showed, as expected, a lower crystallinity index (CI) 52.5 % when compared to Esparto grass samples 55.2 %. The results of the thermal decomposition of natural fibers are shifted to higher temperatures with increasing the cellulose crystallinity. Based on the results of the chemical composition of Diss and Esparto grass, it was confirmed that straw is rich in cellulosic fibers and, therefore, a valuable raw material for the paper and manufacture industry.