关键词: 微胶囊, 木质功能材料, 应用, 发展趋势

Abstract: The functionalization has become an important way to broaden application areas of wood materials, to improve social and economic added values of wood products and to promote transformation and upgrading of wood industry, driven by the increasing market demands and competitions from other materials. The prosperous cross-disciplinary technology of microencapsulation, which is characterized by controlled release and effective insulation, provides a new platform for the development of wood functional materials. Functional units with special electrical, magnetic, optical, acoustic, thermal, mechanical, chemical and biomedical properties are separated into stable microparticles by microencapsulation, which greatly increases their specific surface area and thus enhances their functional effects. According to the specific functional requirement from products, these particles could be evenly imported into wood interior or just concentrated on the surface of wood substrate to prepare durable wood functional materials at a low consumption of functional units. After being encapsulated, wood preservatives generated obviously less harm to environment and human beings, and their release rates became slow and controllable. Microencapsulation could significantly reduce the hygroscopicity of fire retardants and their adverse effects on bonding strength and mechanical properties of wood materials, and efficiently combine the synergetic flame-retardant ingredients. When preparing fragrant wood products, microencapsulation was very suitable for improving the stability of flavors and extending their service period. In the development of reversible thermochromic wood materials, microencapsulation of the thermochromic compositions was an effective approach to improve their stability and durability. In addition, thermal/pressure sensitive functional microcapsules showed great advantages of long storage period, convenience of use and small dosage while being applied to wood materials. Microencapsulation could also be utilized to synthesize controlled-release formaldehyde scavenger, which significantly decreased the emission of formaldehyde over a very long period. Although microencapsulation has injected new vitality into the development of wood functional materials, its application is still in the initial stage. Future researches should focus on the following topics:to realize the quick import and durable bonding for microcapsules by further developing nano-capsule technology and thoroughly studying bonding mechanism between microcapsules and wood substrates; to systematically study the effects of external conditions in production and use of wood functional materials on morphologies, physical and mechanical performance and functional properties of microcapsules, providing theoretical basis for the application of microencapsulation in wood materials; to overcome the incompatibility of different types of functional units by microencapsulation while preparing multifunctional wood materials; to push forward the application of smart microcapsules such as thermalchromic pigments in wood materials, promoting the intelligentization of modern home furnishing; to carry out researches on the standardization of functional microcapsules, guiding a healthy and orderly development of microencapsulation in the field of wood materials.

Key words: microencapsulation, wood functional materials, application, future trends