Research Of High-temperature And Pressure Treatment Process On Performance Of Pinus Massoniana And Hevea Spp.

Heat treatment with pressure, which is a new method to treat wood and could improve the modification quality and treating efficiency, plays a significant role in using and saving the limited wood resources.Pinus massoniana and Hevea spp. were taken as specimens in this paper to study the characteristics of heat treatment with pressure, the treating process are as follows:(1) The heating rates inner Pinus massoniana, whose thicknesses were 20mm,40mm and 60mm respectively, were studied under different vapor pressure conditions.(2) The Pinus massoniana and Hevea spp. were heat treated under the conditions that, the vapor pressures were 0.1MPa,0.2MPa,0.4MPa and 0.6MPa, the ultimate treating temperatures were 150℃, 160℃,180℃and 200℃, and the holding time were 1h,2h and 3h, then the density, dimensional stability, equilibrium moisture content, color and extract of Pinus massoniana and Hevea spp. were measured.The results are as follows:(1) Compared with heat treatment with ambient pressure, high pressure heat treatment holds an obvious advantage when it comes to heating rate inner Pinus massoniana, the heating rate of which was faster than the heat treatment with ambient pressure by 7% to 50%.(2) The correlation coefficients between the density of Pinus massoniana and treating temperature, treating time, treating pressure were 0.757,0.342 and 0.42 respectively, and those of Hevea spp. were 0.551,0.487 and 0.604 respectively; Compared with heat treatment with ambient pressure, high pressure heat treatment was more beneficially to improve the dimensional stability; The correlation coefficients between equilibrium moisture content of Pinus massoniana and treating temperature, treating time, treating pressure were 0.842,0.335 and 0.305 respectively, and those of Hevea spp. were 0.844,0.318 and 0.317 respectively.(3) The correlation coefficients between the vapor pressure and chromaticity parametersΔL*,ΔC*,ΔE* of Pinus massoniana were 0.858,0.743 and 0.86 respectively, and those of Hevea spp. were 0.873,0.474 and 0.624 respectively, which indicate that vapor pressure have significant impact on chromaticity parameters.(4) The measuring results of the content of turpentine inner the treating Pinus massoniana and the extracts inner the treating Hevea spp. demonstrate that:The vapor pressure is the biggest impact factor to the content of turpentine and the deoiling rate. The correlation coefficient between the content of the extract of Hevea spp. and the vapor pressure, which was 0.611, was approximate to that between the content of extract and the temperature, which was 0.601. The equation among the content of the turpentine(y1) inner Pinus massoniana, the content of the extract inner the Hevea spp.(y2), the ultimate temperature(x1), the holding time(x2) and the medium pressure(x3) was y1= 0.938-0.002x1-0.024x2-0.592x3 (R2=0.882) and y2=21.500-0.058x1-0.821x2-5.539x3 (R2=0.856) respectively.