Research On Ultrasonic Characterization Of Particle In Highly Concentrated Polymer Composite

The new materials with performance can be produced by developing particle-reinforced composites. Whether the materials get expected performance principally affected by the dispersion of filled particle in the polymer composite. So it is necessary to measured detect the dispersion of the particle in the polymer composite. As one of mechanical wave detection means with advantages of nondestructive and real time testing, ultrasonic signals are highly sensitive to the materials microstructure. Therefore characterization of filled particle dispersion in polymer composite is important. Modifying model through research on the correlation between the ultrasonic signals and dispersed state. Developing a quick economic, convenient and comprehensive method is of great significance to the development of polymer composite processing industry.Compared with ultrasonic phase velocities, attenuation coefficient is more sensitive to materials microstructure. As the major study this paper chosen differential scheme model research object by comparing different ultrasonic attenuation model. Then setting diverse volume fraction of filled particle(6%, 10%, 20%, 30%, 40%, 50%), particle size(70μm,160μm), distribution state(normal distribution, bi-modal distribution) inside polymer composite acquire the differential dispersion state of the composite samples. Comparing the results between differential scheme model and spectral analytical experimental data from ultrasonic pulse echo method on setting samples, the experimental data verified simulated result and broadened the applied range in highly filled and different distribution composites system.The study shows that:(1) For the normal distribution particle size composite material, when particle size increases,the ultrasonic attenuation coefficient increases while velocity decreases. When volume fraction increases, ultrasonic attenuation coefficient first increases then decreases, while velocity increases. Comparing experiment data with differential scheme model, the results are matched each other as volume fraction reaches 50%. Differential scheme model is applicable to the highly filled concentration and particle size of composites.(2) For bi-modal distribution particle size composite material, when particle volume fraction is equivalent, the higher the proportion of larger particle, the greater ultrasonic attenuation coefficient and smaller the sound velocity. At the same time, the particle size distribution is semblable. When volume fraction increasing, ultrasonic attenuation coefficient first increases then decreases while velocity increases. Through modifying differential scheme model, total attenuation coefficient can be viewed as two components linear superposition. Comparing experiment data with modifying model, the result are matched each other as volume fraction reaches 30%. Modifying differential scheme model is applicable to the differential distribution state of composites.