Compressive behavior of rigid polyurethane foams nanostructured with bacterial nanocellulose at low and intermediate strain rates

Abstract

Nanocellulose reinforced foams are lightweight with improved mechanical properties; however, the strain‐rate effect on their mechanical response is not yet fully understood. In this work, rigid polyurethane foams (PUFs) nanostructured with bacterial nanocellulose at 0.2 wt % (BNCF) and without it (PUF) are synthesized and subjected to compression tests at different strain rates. The BNC acts as a nucleation agent, reducing the cell size but maintaining a similar apparent density of 40.4 ± 3.3 kg m−3. Both BNCF and PUF exhibit strain‐rate effect on yield stress and densification strain. The BNCF exhibits localized progressive crushing and reduced friability, causing a remarkable recovery in the transverse direction. Numerical simulations show that functionally graded foams subjected to impact could be designed using different layers of PUF and BNCF to vary energy absorption and acceleration rate. The results presented herein warrant further research of the mechanical properties of nanostructured foams for impact applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48701.

Nanostructured rigid polyurethane foams with improved specific thermo‐mechanical properties using bacterial nanocellulose as a hard segment

“…This behavior is similar to what the author has found in other PUF formulations. 23,32,45 On the other hand, as it can be deduced from Figure 2, this tendency was not found for the ISO route. In fact, the ΔT MAX decreased to a less extent (8.1 C) and it was not dependent of BNC concentration.…”

A review on recent advances in sandwich structures based on polyurethane foam cores

“…In this regard, a study was conducted to investigate the compressive and low velocity impact response of RPUFs nanostructured with bacterial cellulose at both low and intermediate strain rates. In the study, it was observed that both neat and nanostructured bacterial cellulose PUFs exhibited strain rate effect on yield stress and densification stress, which was primarily associated with the strain rate sensitivity of the base polymer . It has also been observed in a recent study that strain rate has a great influence on other mechanical properties of PUFs and their direction dependence (parallel and perpendicular to the foam rise directions).…”

Mechanical Properties of Natural Fiber Reinforced Foamed Concrete

“…The interest in materials reinforced with natural fibers is growing because it is possible to obtain materials with good mechanical properties, low density and low cost. In addition, natural fibers are biodegradable, renewable and promote sustainability [ 12 , 13 , 14 , 15 ], which is increasingly important currently. These fibers could replace synthetic fibers in certain applications, since synthetic fibers leave a greater environmental footprint.…”