In-situ Preparation And Performance Study Of PA1111/BaTiO₃ Piezoelectric Nanocomposites

Piezoelectric Polymer/ceramic nanocomposites have attracted widespread attention for their prospect of application in many energy-related areas,such as energy harvesting,energy transformation and energy storage.PA1111/BaTiO₃ nanocomposite designed here is supposed to combine the high dielectric property,piezoelectricity of BaTiO₃ and the easy molding,outstanding mechanical properties of PA1111.The prospecting better comprehensive performance of PA1111/BaTiO₃nanocomposite will meet the urgent demand from the flexible electricity manufacture.In this paper,a series of PA1111/BaTiO₃ nanocomposites with mass fraction varying from 0%to 10.0%were prepared via in-situ salification-melt polymerization process.In detail,tetragonal BaTiO₃ nanoparticles were well dispersed in undecanedioic acid-alcohol solution before 1,11-undecane diamine were added in.After the in-situ salification,PA1111 salt/BaTiO₃ composite was further conducted melt polymerization in a batch autoclave to in-situ synthesis PA1111/BaTiO₃ composite.FTIR,TG and DLS were utilized to analysis the salification process.It showed that the addition of BaTiO₃ did not affect the formation of PA1111 salt,and the interaction between BaTiO₃ and undecanedioic acid ensured the well dispersion of BaTiO₃ in PA1111 salt and further hindered the aggregation of the nanoparticles in the polymerization process.XRD and DSC results proved that the melt polymerization did not affect the crystal form of BaTiO₃,which was still a ferroelectricity-favored tetragonal phase,and BaTiO₃ nanoparticles played a role of crystallization inducer for polymer matrix.SEM and TEM investigation demonstrated that the uniformly dispersing situation of BaTiO₃ nanoparticles in PA1111 matrix was achieved by designed in-situ compositing process.The electric property of the series were then characterized.The dielectric constant climbed up along with the increasement of BaTiO₃ content,while the loss tangent almost stayed unchangeably.Theβrelaxation of nanocomposites moved toward higher temperature zone along with the increasing BaTiO₃ loading.The piezoelectric strain constant(d₃₃)and piezoelectric voltage constant(g₃₃)of the nanocomposites increased with the addition of BaTiO₃nanoparticles,and reached the maximum when the loading of BaTiO₃ nanoparticles was 10.0 wt.%,which was 2.6 times and 2.4 times of pristine PA1111,respectively.The ferroelectricity investigation of the nanocomposites showed that the remnant polarization（P_r）and coercive field（E_c）increased with the decreasing of frequency period and the increasing of applied electric field.When the electric field intensity was900 k V/cm,the test frequency was 0.05 Hz,and BaTiO₃mass fraction is 7.5 wt.%,Ec and Pr of the nanocomposites were 217.22 kV/cm and 0.3671μC/cm²,respectively.