Compressive properties of closed-cell polyvinyl chloride foams at low and high strain rates: Experimental investigation and critical review of state of the art

Closed-cell foams are widely used in marine vessel and ground transportation applications due to their compressive energy absorption capabilities, especially as the core material in sandwich composites. In the present work, a set of closed-cell polyvinyl chloride (PVC) foams with different densities is studied for compressive response at a wide range of quasi-static and high strain rates. The results show that the mechanical properties depend on the foam density and are strain rate sensitive. The compressive strength and modulus increase with the foam density. Cell wall buckling is observed prominently in high density foams, whereas low density foams show wrinkling and stretching of cell faces. An extensive literature survey on PVC foams is presented in this work and the mechanical properties reported in published studies are analyzed to understand trends and future directions. It is found that within the quasi-static strain rate regime, the compressive strength of PVC foams can be up to 50% higher at 10^-1 s^-1 compared to 10^-4 s^-1. At strain rates of 2000 s^-1, the strength can be 200% higher than the quasi-static values noted at 10 ^-4 s^-1. Absence of experimentally measured mechanical properties in the intermediate strain rate range of 1-500 s^-1 is noticed for PVC foams. Scanning electron micrographs show cell wall buckling followed by folding as the compressive failure mechanism.