Prepapation Of Damping PU/PZT Piezoelectric Composites And Research On Properties Of Sound Absorption

The noise pollution has become one of the three worst problems ofenvironmental pollution in the world, which jeopardize our health seriously. Thekey factor to solve this problem is developing efficient sound absorption materials.Polymer piezoelectric ceramic composite materials showed its broad prospects duoto his high mechanical strength, resistance to environment and better soundabsorption for low-frequency. Therefore, the development of this material is ofgreat significance to solve the problem of noise pollution. This paper is research onthe structural design, preparation and the properties of sound absorption of PU/PZTcomposites.From the perspective of molecular structure, we designed a kind of T-typepolymer chain segments, the structure contains long polypropylene glycol (PPG)main chain and flexible side groups. The damping polyurethane was prepared byprepolymer process with PPG as soft segment and TDI as hard segment. The DMAmethod showed that the damping temperature range reached60℃(-40℃-20℃), themaximum tan value reached to0.62. The DSC showed that with the increasementof the free isocynate content, the crystallization melt peak become larger of hardsegment, which reflected the increase of hard content. Meanwhile, the effect of PPGmolecular weight, the kind of cross-linking agent and isocynate content on themechanical was discussed.The sintering temperature of PZT ceramic was droped from1250℃to900℃by optimizing the two-stage mixed oxide synthetic route. The XRD showed that thePZT ceramic was pure perovskite phase, SEM showed that the internal structure isdense. The d33constant of PZT ceramic reached to267.3pC/N in the polarizationvoltage of5kV/mm.The PU/PZT composites were prepared by situ polymerization process, theeffect of PZT surface property and content on the property of PU/PZT were studied.SEM showed that PZT and PU can combinated well, and the PZT disperseduniformly in PU with the maximum content of30wt%. DMA showed that the PZTcan obviously broden the damping temperature range (70℃), and the damping losspeak towards the higher temperature. The tensile tests showed that the tensilestrength increased by57.01%, the thermal gravimetric analysis showed that thedecomposition temperature increased by30℃.The damping and piezoelectric sound absorption mechanism were effectivelycombined to form a broad-band sound-absorbing material structure, The standing wave tube was used for testing sound absorption property, the results showed thatthe PU can absorbed the noise well, especially for the low frequency sound wave.PZT piezoelectric phase and MWCNTs conductive phase were added to improve thesound absorption coefficient of PU/PZT composites, the sound absorptioncoefficient reached to0.55in250Hz and the average sound absorption coefficientin125-4000Hz reached to0.48, which increased by285.4%and48.8%separatelycompared to the PU. The problem of can be solved well for sound absorption in lowfrequency.Inorder to improve the sound absorption coefficient in the high frequency, weprepared the PU porous foam and PU/PZT composites, this new structure materialsshowed excellently sound absorption property in the broad frequency range of125-4000Hz, the average coefficient reached to0.56, increased by15.5%. Thesound absorption mechanism of composites was explored based on the mode ofinteraction and the energy conversion forms.