Preparation Of Polyurethane And Research On Underwater Acoustic Properties Of The Polyurethane

With the rapid development of economy, countries are also increasing emphasis on military. Submarine is recognized as a strategic weapon, which requires a highly developed and comprehensive industrial capacity. With the gradual increase of the performance requirements of the submarine structure, its functional performance requirements are also increasing, which is a decisive factor in acoustic stealth performance of their combat effectiveness.Underwater sound absorption material has a certain mechanical requirements, thus the study on mechanical properties superior underwater sound-absorbing material is very important.Due to the characteristics of polyurethane acoustic impedance and transmission characteristics of the medium water acoustic impedance matching,and the material has the very high internal friction. This article obtains from the underwater sound-absorbing material, and put PU porous material as the main absorption material.Study the structure of polyurethane porous material and packing material and its sound absorption performance and the relationship between the mechanical properties. The research to promote the polyurethane materials in the field of underwater acoustic applications is of positive significance, but also provides some theoretical basis for the submarine stealth design.Based on the sound absorption performance of its main influencing factors, We design the PEG2000 as the soft segment, TDI and TEA as hard segment of polyurethane molecular chain structure. The study found that the material molecular structure affect its molecular chain flexibility and micro phase separation degree,which will affect the absorption of the material performance and mechanical performance. When hard segment content is 24.08%,the glass transition temperature Tg of the materials is lowest which reaches 43.39 ℃. The material of chain is more smooth, more advantageous. Material produce micro phase separation. At this time, in 3 ~ 16 kHz frequency, the average sound absorption coefficient of the materials is 0.66.At the same time, this paper studies the catalyst DBTDL and foaming agent of polyurethane material, the results of the influence showed that two kinds of additives has no effect on the molecular structure of materials, but there is a great influence on the pore structure.when the catalyst content is 0.4% and water content is 3%, the comprehensive performance of materials is the best and the average sound absorption coefficient of the material is 0.74.In addition, in this paper, polypropylene fiber and hollow glass beads applied to the polyurethane foam material for packing modification.And the results show that the effect of the hollow glass beads on the material is better.When the content of hollow glass beads was 20%, material deformation under the 5 mpa stress was only 32.2%, and the average sound absorption coefficient is 0.86, which is increased by 16.2% compared with adding no hollow glass beads.