| Wood-rubber composite (WRC) is a new kind of functional composite which comes up in recent years. It has many good performances, for example, waterproof, antiseptic, mothproof, antistatic, soundproof and sound absorption, vibration damping, heat insulation, and so on. Therefore, it can be widely used as indoor decoration materials for sound insulation, vibration damping and heat insulation. The development of WRC will show high-efficient utilization of wood, pollution-free recycled utilization of waste tyre and high-added value of forest products. Therefore, this composite has broad prospects. However, as the research work is just in a beginning stage, the industrialized production of WRC has not been realized yet.In order to gain a deep study on WRC, a lot of correlative literature was consulted, and the bionic design of WRC is obtained based on cork microstructure. According to the structure model, WRC was made of plantation wood, woodwork remainder and waste tyre particles. The main factors which affect the performances of WRC were studied in this paper. In addition, the soundproof mechanism of WRC was disclosed through experimental modal analysis. At the same time, the application of WRC in manufacturing wood-based soundproof flooring was experimentally studied, and the manufacturing process, performances and economic benefit were analyzed. The testing method of soundproof property was also studied.The main research results are as follows:1) In the bionic structure of WRC based on cork microstructure, wood particle is just like the cell wall, playing the role of supporting and filling. In WRC, wood particle is the strength element, which shows physical and mechanical properties; The rubber, just like the gas enclosed in cork cell lumen, plays an important role like spring in vibration damping; And adhesive is in some degree like the suberin with the function of connection.2) The main relationships of process and performance are as follows:The mass ratio of wood to rubber has a significant effect on the performances of WRC. With the reduction of the ratio, the amount of rubber particles increases, which makes the water absorption and swelling resistance of WRC increase, and makes the internal bond strength, modulus of rupture, modulus of elasticity, natural frequency and impact sound decrease; But, on the contrary, the damping ratio and improvement of impact sound insulation increase.The configuration of wood particles has a significant effect on the performances of the composite. Better physical and mechanical properties can be gained using flat wood particles and fibre. C-type wood particles can make WRC with lower natural frequency and impact sound, higher damping ratio and improvement of impact sound insulation.The resin content has a significant effect on the physical and mechanical performances (except thickness swelling rate of water absorption within two hours), but it does not have obvious effect on vibration and acoustic performances according to the results of experiment.The density of the composite has a significant effect on physical and mechanical, vibration and acoustic performances. WRC with the target density from 0.8 g/cm3 to 1.0 g/cm3 has better comprehensive performances.The interaction of the mass ratio of wood to rubber with the resin content, and that of the density with pressing time have some significant influence on the performances. Therefore, the interaction should be taken into account when process parameters are adjusted.3) In order to obtain better vibration and acoustic performances, the better process parameters are as follows: C-type wood particles, 2-3 mm waste tyre particles, the mass ratio of wood and rubber 40/60, the resin content 6%, the target density 0.8 g/cm3, the pressing time 4 min and the hot pressing temperature 140℃. By adopting the optimized process, the main performances of WRC are as follows: density 0.78 g/cm3, thickness swelling rate of water absorption within two hours 3.12%, internal bond strength 1.1 MPa, modulus of rupture 3.8 MPa, modulus of elasticity 342 MPa, natural frequency 17.4 Hz, damping ratio 0.15, impact sound 76.5 dB(A) and the improvement of impact sound insulation 15.5 dB(A).4) The mechanism of soundproof of WRC: Low natural frequency and high damping ratio due to the existence of large amount of rubber particles in the structure. Under the load of impacting, it is easy to generate sympathetic vibration because of the narrow space between different order frequency, and then the rubber particles'function of vibration damping and power absorption can be fully realized. At the same time, higher damping ratio can attenuate vibration. More energy dissipated in the course of transmission can reduce energy dissipation in the form of sound, thus vibration and noise are also decreased.5) The soundproof property can be evaluated with two parameters: impact sound and improvement of impact sound insulation. A new method called free-dropping-ball impacting method was put forward for testing soundproof property, and a set of testing system was designed and prepared. The feature of this testing method is: a few samples, easy and quick test and precise evaluation. This research will offer a new idea for drafting and developing testing method standards of wood-based soundproof flooring in future.6) The better soundproof and physical mechanical performances can be achieved through changing the structure of WRC-based soundproof flooring; Under exterior load, three kinds of forces are acted on WRC layers (tension, extrusion and shearing). There are two types of bending failure for WRC-based soundproof flooring.
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