Preparation Of Polyacrylate Damping Materials And Their ?' Transition Studies

Polymer damping materials are widely used for absorb vibration and noise-reduction in military and civilian fields,which damping functional area is the galss-rubber transition zone.Acrylate polymers usually be used as damping materials for their excellent performances,such as high temperature resistance,oil resistance,bonding properties and mechanical properties.The ?' process together with a transition can form a broad and strong damping dissipation peak in the glass-rubber transition zone of amorphous polymers,which can improve the damping properties.However,?' process of acrylate polymers are usually suppressed for the strong intermolecular coupling effect.The contribution from ?'process to damping performance can not be displayed.The release of ?' process of acrylate polymers is of significance to broaden its damping temperature and improve damping performance.To release ?' process of acrylate polymers,two kinds of copolymers P(MMA-co-BMA)and P(BMA-co-LMA)were prepared,which the two comonomers structure units have certain different glass transition temperature.The structure and molecular weight of copolymers were studied by FT-IR,1H-NMR and GPC.The results show that the copolymers were synthesized successfully,their molecular weight meet the requirement of viscoelasticity research.The thermal and dynamic mechanism properties were studied by DSC and DMA.It was found that incorporating a small amount of BMA structure units,the Tg of P(MMA-co-BMA)increased rather than decreased compared with PMMA.The relationship between Tg and composition is not consistent with the describe of Fox and Gordon-Taylar et al.Equations.The full width of half maximum(fwhm)of tan?reduced at first then raised.The rubber platform modulus increased at first and then decreased,the maximum was obtained at BMA content of 2.06%.According to relaxation time spectra and 2D-DMA spectra,it indicates that the degree of entanglement of molecular chains increased when incorporating a trace amount of BMA soft structure units,local segment movements were more different,the overlap between different motion rose,so the modulus and Tg increased,fwhm of tan? deceased.When BMA acts as main monomer structure units,and MMA structure units is very low,the tan?max of copolymers were higher than that of PBMA.The tan8 exhibited a asymmetric double peaks at MMA content of 2.43%,the ?' process of copolymer was released to a certain extent.Compared with PBMA,its fwhm and area of tan? were significantly improved,increased 38.30%and 39.17%,respectively.For P(BMA-co-LMA),the results of DSC and DMA show that the Tg of copolymers decreased with the raised of LMA content,unlike P(MMA-co-BMA),there is no obvious deviation from Fox equation.The tan? also exhibited a significant asymmetric double peaks at LMA content of 2.04%,?' process was released,compared with PBMA,the fwhm and peak area were increased 25.93%and 24.08%,respectively.Although the relationships between relaxation transition behavior and composition of the two kinds of copolymers is not exactly the same,the tan? can display remarkable asymmetric double peaks,?' processes were released,the damping performance were improved.The PBMA/Fe3O4 and PBMA/composite particles blends were prepared by emulsion blending.Composite particle was compound of Fe3O4 and graphene.The particle size and size distribution of inorganic particles were measured by laser particle size analyzer.The results show the particle size is in micron level and the size is homogeneous.The apparent morphology of composite particle was observed by SEM,the result shows Fe3O4 was wrapped by graphene and the composite particles show a uniform sphere.The dynamic mechanism properties of blends were researched by DMA.The results show the maximum of tan?max and its peak area can be obtained at Fe3O4 content of 3.30%.When the content of composite particles is 5.50%,the tan? also shows a double peaks structure.Namely a'process of PBMA/composite particles blends was released successfully.All the tan?max,fwhm and peak area increased prominently.This indicates that the ?' process can be released by blending,the damping temperature range of polymer damping materials were broadened,and the damping properties were improved.