Determining the elastic properties of modified polystyrenes by sound velocity measurements

Abstract

The effect of the binding of various polyfunctional groups to polystyrene's (PS's) aromatic ring on the elastic properties of the PS were investigated by an ultrasonic method. Various sets of samples were prepared by chemical modification of pure PSs having different molecular weights with SA, maleic anhydride, and phthalic anhydride. The ultrasonic wave velocities of modified PSs were measured with the pulse-echo method at room temperature by a computercontrolled analyzer and a digital oscilloscope. The values of the acoustic impedance, Poisson's ratio, and elasticity constants of the samples were calculated by the measured values of the densities and sound velocities. The longitudinal and shear wave velocities and the values of all elastic constants increased with chemical modification of the pure PS.

Ultrasonic properties of polystyrene‐based composites

“…It can be stated that different functional groups may affect mechanical properties of composites in different ways. To understand the effect of molecular structure, three various carboxylic (COOH) functional groups with aromatic, saturated aliphatic and unsaturated aliphatic parts in case of PhA, SA, and MA, respectively are specifically studied 60. As seen from Figure 1, when pure PS modified with SA, COCH 2 CH 2 COOH polyfunctional group was bound to aromatic ring of pure PS, when pure PS modified with MA, COCHCHCOOH polyfunctional group was bound to aromatic ring of pure PS and when pure PS modified with PhA, COC 6 H 4 COOH polyfunctional group was bound to aromatic ring of pure PS.…”

“…One of the important results of this study is that showed that the best way for improving the mechanical properties of pure PS is to producing CPSs. In fact the researches60, 85, 86 made before had shown that modifying PS with various organic anhydrides, increases the elasticity properties of PS. But modifying PS by various anhydrides is an expensive way.…”

“…It was seen that this process improved the properties of PS. Modified PSs were found to have higher mechanical and elasticity properties than PS had and they were more durable against impact 60. But because that this process was an expensive way, as continue of the first part of the study, this study was done.…”

Determining the mechanical properties of epoxy resin (DGEBA) composites by ultrasonic velocity measurement

“…Included amongst these are medical imaging, dentistry, particle sizing, food processing, welding, waste water treatment, and surgical processes 25. Furthermore, ultrasonic methods have been successfully used to monitor polymer processing,26 chemical reactions,27, 28 film formation from aqueous polymer dispersions,29 glue processes, crystallization in polymers,30, 31 and also characterization of polymers 32. Thus, recently, a lot of attempts have been made to study the sound velocity and attenuation of polymers 33–42.…”

“…There are weak electrostatic gravitational forces (e.g., van der Waals forces, hydrogen bonds) between the molecular chains. These van der Waals forces and hydrogen bonds keep the chains of molecules close to each other 32, 45. The longitudinal modulus is related with bonds which creates the polymer chains between monomers.…”