Compressive response of PMMA microcellular foams at low and high strain rates. Issue 13 (1st December 2017) - Zhang, Ruizhi
ABSTRACT: Microcellular foams are widely applied in various applications in both civil and military applications for barriers and energy absorption materials. Poly(methyl methacrylate) microcellular foams were fabricated via supercritical foaming method. Field emission scanning electron microscopy, differential scanning calorimetry, and mechanical test machine were used to visualize the foam structure and test the quasi‐static compression properties. Moreover, Split Hopkinson Bar (SHPB) setups were adopted to explore the dynamic compression properties. The experimental results show that the microcellular foams have homogeneous cell size distribution and exhibit superior compressive behavior at both quasi‐static and high strain rates. The mechanical properties depend on both foam density and strain rate. Strain rate effects are clearly observed. At quasi‐static strain rate and 7500 S −1 regime, cell wall bucking and folding are the main failure mechanism. However, at high strain rate regime, softening phenomenon is observed. By roughly calculating the energy absorbed and the temperature rise, the temperature of the foams will rise up to as high as 130 °C after conducting high strain rate compression, and it is postulated that the generated heat will destroy the cell structure of the foams. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018, 135, 46044. Abstract :