Research On Technics And Property Of Mongolian Scotch Pine After Thermal Treatment With Pressure

China is a country with a short supplay of wood resource but a large size of population. Functional amelioration of wood is an effective method to alleviate the contradiction of wood supply and demand. Thermal treatment on wood with pressure is one of the important methods which can fully make use of wood resource, improve the comprehensive usage rate of wood, and meet the demand of natural, comfortable and pleasing to both the eye and the mind of people.Technics and property of Mongolian scotch pine which is treated at different temperatures(200℃,225℃,250℃), under different pressures(0.20MPa,0.40MPa,0.60MPa),treated with different hours(4h,6h),of different thickness(15mm,20mm) and of the flatsawn and quartersawn, are systematically investigated in this thesis. According to the influence of the five factors on the properties of Mongolian scotch pine, different technics can be designed to meet various demands.Based on related documents and large amount of prior tests, 45 kinds of technics are applied to treat Mongolian scotch pine. Related properties of treated wood at high temperatures and under high pressures have been studied. By analysis, the results are as follows:(1)In terms of color of Mongolian scotch pine, temperature, pressure, and the flatsawn or quartersawn are the factors which mainly influence the color parameters L~*,a~* ,b~*, and total color differenceΔE. The color of the wood becomes darker when the processing temperature and pressure are higher. As a conclusion, we can choose the quartersawn Mongolian scotch pine which is of 15mm or 20mm thickness, to be treated at 250℃,under the pressure of 0.60MPa for 4 hours as the optical processing condition.(2)In terms of physical properties, temperature is the notable factor influencing the density, water absorption, swelling and shrinkage of Mongolian scotch pine. Pressure remarkably influences the density, tangential and volume swelling of the wood. The flatsawn and quartersawn are the main factors affect the water absorption, radial swelling and shrinkage. Processing hours and thickness of the wood are the inapparent factors. In conclusion, the quartersawn Mongolian scotch pine which is of 15mm or 20mm thickness, to be treated at 225℃,under the pressure of 0.40MPa for 4 hours can be selected as the optical processing condition.(3)In terms of mechanical properties, temperature is the indistinctive factor to the maximum bending strength, MOR, MOE, impact strength of treated Mongolian scotch pine. However, when compared with the untreated samples, temperature has a great impact on the wood. When processing temperature ranges from 22℃to 250℃, the maximum bending strength, MOR (W= 12%), MOE(W=12%)and impact strength decrease 39.17%, 46.55%,25.79% and 41.10% respectively. Pressure apparently influences the MOR, MOE of the wood. 0.20MPa and processing 4 hours are the best choices. The flatsawn is better than the quartersawn. So the quartersawn Mongolian scotch pine which is of 15mm or 20mm thickness, to be treated at 225℃,under the pressure of 0.40MPa for 4 hours can be selected as the optical processing condition. Treating the quartersawn wood at the temperature of 225℃,under the pressure of 0.40MPa for 6 hours is the worst choice.(4)In terms of contact angle, compared with that of untreated Mongolian scotch pine, it decreases gradually, that means the surface free energy increases, and the wettability gets better. When the wood is treated at 225℃,under the pressure of 0.40MPa, the contact angle is the smallest. Then we know in this situation, the wettability is best.(5)Above all, the optical processing condition is to choose the quartersawn Mongolian scotch pine which is of 15mm or 20mm thickness, being treated at 225℃, under the pressure of 0.40MPa for 4 hours.Through treatment, the dimension stability and wettability of Mongolian scotch pine were improved to some great extend though strength characters have decreased at different degree. In addition, the mechanism of thermo-treatment wood is also discussed. With studying FTIR of the treated wood, a qualitative analysis for the interior structural change is studied, to provide the basic data and analytical evidence for future research.