| Viscoelastic damping material not only has high absorption and vibration capacity,but also has the characteristics of light quality,easy to design and easy to process.It has been widely used in the fields of weapons,equipment,transportation,precision instruments and so on.Because the damping characteristic of this kind of material is produced by internal friction of the polymer chain section,it has significant damping performance in the glass transition temperature(Tg)range.Because of the narrow Tg range of polymer materials,the widening of temperature range is a difficult and hot topic for damping materials.Damping materials have potential applications in full space exploration,aerospace vehicles,cryogenic and high-precision electronic devices.At present,the viscoelastic damping material exists the contradiction between the damping temperature field and the loss factor,which seriously restricts the use of damping materials in industry and national defense.In this paper,the inorganic piezoelectric/polymer viscoelastic damping composites are designed,and the damping mechanism and damping contribution of the piezoelectric materials are studied in detail.The main work and results of this paper are as follows:(1)The blend system of bisphenol A(DGEBP A)epoxy resin(DGEBP A)and polypropylene glycol epoxy resin(PPGDGE)was prepared.Polyether amine(D230)was used as a curing agent,and FTIR confirmed that the crosslinking network solidified completely;SEM,DSC and DMA were used to characterize the profile of the solidified substance and the mechanical behavior of the thermo machinery.The results show that compared with the pure DGEBP A/D230 system,the DGEBP A/PPGDGE/D230 system presents ductile fracture,and the effective damping temperature range is widened,but the loss values at the time of the glass state are both flat.(2)In the DGEBP A/PPGDGE/D230 system,Lead magnesium zirconate niobate lead titanate(PMN-PT)piezoelectric powder and conductive carbon nanotube(CNTs)are introduced,and the dual composite damping network of flexible epoxy resin organic 3D network and piezoelectric/conductive inorganic 3D network is constructed,and the two have damping synergy effect.The effects of the amount of piezoelectric ceramics and carbon nanotubes on the formation and damping properties of the conductive network were studied in detail by DMA.The results show that the damping effect of the resin can be slightly enhanced when the piezoelectric ceramics and carbon nanotubes are used alone,but the trend of the damping is increased with the increase of the amount.The feasibility of the piezoelectric damping mechanism is verified by the study of the piezoelectric ceramics of 20wt%and 60wt%.By comparing the damping properties of carbon nanotube/epoxy resin composites before and after the modification,the modified carbon nanotubes are beneficial to the damping property of the composites.On this basis,when using PMN-PT/CNTs(OH)piezoelectric conductive system,When the PMN-PT/CNTs(OH)piezoelectric conduction system is used,the addition amount of(PMN-PT)is 10wt%and the conductive phase is alkaline carbon.When the addition of CNTs(OH)is 0.2wt%,the best damping effect is achieved.The loss factor of the glass state is increased by 8 times,and the effective damping temperature range is widened to 2,indicating the synergistic effect of the two.The piezoelectric phase lead,lead zirconate titanate and lead titanate,proved the importance of the percolation threshold on the piezoelectric damping composite,and the addition of the piezoelectric ceramics should be controlled within the 20wt%.(3)A double composite material damping network is formed by the formation of a self-conductive circuit and the DGEBP A/PPGDGE/D230 system by a silver coated electric ceramic.At this time,the maximum loss factor of the double composite material is increased by 0.3 and the effective damping temperature range is reduced by 2 compared with the external conductive circuit.At the same time,the pressure is studied by changing different frequencies,loads and electrical circuits.The damping capacity of the composite material provides an experimental basis for the piezoelectric damping field. |
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