Study On The Surface Density For Chinese Fir Of Plantations

For the shortcoming in Fast-growing Chinese fir of plantations material loose and low intensity, In order to explore the new ways for the efficient and effective using, We treated with it by surface densifying. Studied it about processing property and influencing factor in Densify of the surface compressing, the surface resin immerse, the surface resin immersing and compressing wood. The main results as follow:(1) Densify of Fast-growing Chinese fir of plantations with the surface compressing, the surface densify wood made by the sapwood and heartwood of Fast-growing Chinese fir, which used microwave softening and surface compressing. The result shows that: The influence of Microwave treatment times to ASE and response rate of the surface compressing densify sapwood is marked, to ASE of heartwood is marked, and to MOR is little more. The influence of Microwave treatment power to MOR and ASE of the surface compressing densify sapwood has much more. The influence of Moisture content to ASE, response rate of the surface compressing densify sapwood and heartwood is marked, The influence of compressing rate to ASE and response rate of the surface compressing densify sapwood is marked, to MOR, ASE and hardness of heartwood is little more.(2) Densify of Fast-growing Chinese fir of plantations resin with the surface immersing. The surface impregnating densify wood made by Fast-growing Chinese fir, which used for standard atmosphere immersing, microwave fore-treatment and pressure immersing with common water-solubility PF. The result shows that: The best standard atmosphere impregnating densify process are: 25% of moisture content, 15% of the adhesive concentration, 24h of impregnating time. The best compression impregnating densify process are: 3min of microwave fore-treatment, 640W of microwave power, 0.4Mpa of impregnating presure and 3h of impregnating time.(3) Densify of Fast-growing Chinese fir of plantations with the surface resin immersing and compressing. The surface impregnating and compressing densify wood made by Fast-growing Chinese fir, which used for immersing with low molecular weight and water-solubility PF, microwave soften, the surface compress and so on process. The result shows that: Chinese fir of plantations after impregnating and compressing treatment, Bending Strength and Modulus of Elasticity are increasing 45.8%,29.9%; abrasion resistance are lower 32.9%; hardness of three section are increasing, deformation recover have been fixation. The More appropriate process condition is 800W of microwave power, 5min of softening time and 30% of compression rate, 35% of the adhesive concentration.(4) Fourier transform infrared spectrometer analyses shows that Cellulose, Fast-growing Chinese fir of plantations after the surface densify, hemi-cellulose and lignin molecules have been reduced, parts of wood Cellular and some group of resin molecule occured cross linking reaction and form a new group.(5) Fast-growing Chinese fir of plantations after microwave fore-treatment , Although weakness of tracheid have been destroyed, but the penetrability have enhanced and increased the absorption of resin that make some performance of the surface density Chinese fir improved.(6) Fast-growing Chinese fir of plantations after the surface immersing and compressing densify, Time to Ignition has been extended, Smoke Produce Rate and Heat Release Rate have been Postponed, Peak of Smoke Produce Rate and Heat Release Rate have been suspend, Total Smoke Rate have been reduced.