The Optimization Process And Application Of Wood Surface Coating

Wood is composed of the three element which is cellulose, hemi-cellulose, and lignin, three element's absorbent make wood has becomed a kind of material to easy absorption water, that great impact of the use of wood, so make wood have water proofing property has great significance. The parylene thin film of this thesis is xylene polymer, it is a kind of thermoplastic polymer materials, in the process of coating, the monomer of vapor deposition and film forming almost simultaneously, there is no liquid phase transition state, and generally conducted at room temperature, it can be very uniform, coated with a pinhole in any shape of the objects on the surface, get a layer has good biological inert, mechanical properties, electrical properties and chemical inertness transparent film. This paper use the performance of parylene thin film and use a special process of vacuum evaporation coating to modification to wood surface, deposits a layer of parylene thin film on the wood surface, so as to improve the waterproof performance of wood, timber anticorrosion performance, resistant to pollution, improve the flame retardant wood hygroscopicity big shortcoming.First of all, because of the wood surface are non-polar surface, but parylene thin film belongs to polarity surface,there has the certain difficulty when combined with this two surface, so we need to take some surface pretreatment methods to improve the combination of these two interface, make the combination of these two interface is activated, to send to pull molecular deposition on wood surface.There are three kinds of surface pretreatment method, such as wood surface coating method of coupling agent, wood surface plasma processing method and the combined processing method. A coating test after using three kinds of surface pretreatment method, then measure the performance of the coated specimen, such as analysis of the coated specimen waterproof performance, surface wettability and the free energy on the macroscopic and analysis the film thickness of the coated specimens on the microscopic, research the three kinds of surface pretreatment method to impact on the wood surface coating process. Results show that the joint surface treatment method has the best effect, compared with the untreated sample, the maximum water absorption of joint surface treatment and coated sample decreased from 119.67% to 20.04%, down 99.63%, contact Angle increased from 79.4 ° and 147.28 °, increased 67.88 °, surface free energy fell to 6.49 j.m-2 from 47.88 j.m-2,decreased 41.21 j.m-2; Coating after the surface pretreatment of specimens compared with direct coating specimens, maximum water absorption decreased from 24.4% to 20.04%, down 4.36%, contact Angle increased from 128.53 ° to 147.28 °, increased 18.75 °, surface free energy from 9.64 j.m-2 to 6.49 j.m-2, decreased 2.97 j.m-2, film thickness increased from 29.5 um to 32.1 um, increased 2.6 um. All the performance shows that the surface pretreatment to improve the interface of wood and films, make for parylene thin film deposition on the surface of wood, optimized the wood surface coating process.Then, through the design of orthogonal test to study the optimal technology of film coating of wood surface coating, and analysis of orthogonal test results, film thickness under the different process, waterproof performance before and after coating wood, and use of the SEM and FT-IR to analysis of wood coating surface morphology and chemical changes before and after the coated, through comprehensive analysis of various, we get the optimal process of wood surface coating. The results show that the optimal process of wood surface coating is: coating time 5h, coating temperature 100 ?~105 ?, the coupling agent content is 3%; And waterproof performance of wood after the optimal coating process has improved significantly, the mensuration, maximum water absorption by 119.62% decreased to 14.72%, the coating of the contact Angle of coating increased 79.4 ° to 132.08 °, at the same time, the slice after coating wood dyeing under a microscope, visible form a layer of thin film, using the optimal technology of coating film thickness was 31.4 um.Finally, this paper studied the application of the coated wood. Reference standard “Wood preservative performance evaluation of field test method for buried” and “Thermosetting resin decorative laminate surface pollution resistance measurement” to explored the new performance after wood coated. Results show that the decay resistance rating of 10 and fouling resistance value summation of 30 which coated wood, the decay resistance grade 6 and fouling resistance value combined to 39 without coating modified. At the same time, the fouling resistance value is 5 reagent, measuring its pollution total depth, coating group is 0.17 mm, not coating group is 0.63 mm, significant difference, proved that the coating modification can effectively improve wood anticorrosion performance and surface pollution resistance. This thesis also to explore whether coating modification can improve the flame retardant shortcomings of wood moisture absorption is strong through fire retardant treated wood coating. The results show that the coating of the modified flame retardant wood, maximum water absorption rate fell to 152.59% from 152.59%, the effect significantly, the coating modification can effectively improve the flame retardant wood easy bibulous shortcomings. At the same time, through the halogen experiments, the coating modification effectively suppresses the halogen flame retardant wood reaction, give the good performance of flame retardant wood waterproof, moistureproof.The excellent properties which wood surface coating modification give wood expanded the use of wood in the daily life, and provide a theoretical basis and technical guidance for the use of wood in various harsh environment.