Dynamic Response of Filled Elastomers

Abstract

Polymers with rubber-like elasticity, also known as elastomers, are among promising candidates in ballistic protection products (armors) due to their low weight and high energy dissipation characteristics. Dynamic mechanical properties of elastomers, including their damping factor, can be enhanced by incorporations of fillers which are also expected to improve the ballistic protection capability of armor systems. In this study, dynamic response of such elastomers filled with micrometer-size carbon fibers at various high rates and temperatures above their glass transition is directly assessed using split-Hokinson pressure bar (SHPB). The dynamic mechanical analysis (DMA) test results are then compared with these direct measurements using timetemperature superposition (TTS) principle to construct frequency domain mastercurves, yielding stiffness and loss properties over a wide range of frequencies. It is observed that the incorporation of fillers within an elastomeric matrix can significantly increase its strength and stiffness while maintaining the loss properties. The effect of fillers volume ratio is further studied. It is shown that, although increasing the volume ratio can improve stiffness, the elastomer composite with excess amount of fillers will have higher induced shear stress between the matrix and fillers. The higher volume fraction of fillers can also increase the prospects of introducing more defects which at the end can negatively affect the ultimate toughness of the composite. This work may pave the way for designing more effective ballistic protection products at various impact speeds.