ПОЛЗУЧЕСТЬ И ОБРАТНАЯ ПОЛЗУЧЕСТЬ НАТУРАЛЬНОЙ И ПЛАСТИФИЦИРОВАННОЙ ДРЕВЕСИНЫ БЕРЕЗЫ ПРИ ПРЕССОВАНИИ ПОПЕРЕК ВОЛОКОН

Abstract

Pressed (modified) wood is a technological process of drying, impregnation and pressing (R 54577-2011 State Standard). The density of pressed wood, depending on the degree of pressing, ranges from 750 to 850 kg/m3. Strength, hardness toughness of this wood is several times greater than of natural wood. Coal oil, TCL (thermocatalytic cracking liquid), shale oil are most often used as wood antiseptics. They are plasticizers and change the nature of deformations during pressing.Experiments with natural and were conducted to obtain comparative data. Pressed wood contained 10% of TCL oily antiseptic by weight of absolute dry wood. Birch wood was used as the starting material. In this case, an antiseptic agent in an amount of 8-10% by weight of dry wood is evenly distributed over the entire cross section of the specimen. Direct and reverse creep was studied to assess time changes in deformation composition of wood, pressed across fibers. Measurements of direct and reverse creep of wood were carried out on a lever installation. The obtained modes can be used to optimize the technology of obtaining plasticized wood, because plasticization of wood with TCL oil reduces toughness 3-5 times (in the first phase of deformation), in the second phase - 1.1-1.5 times, in the third phase - 2.5-3 times. Transverse strain coefficient increases 1.2-1.3 times. Using creep curves of plasticized wood, it was found that oil impregnation gives 4-5 times greater reduction in the proportion of elastic deformations and, accordingly, increases the residual ones.