Behavior of novel sandwich panels with cork/polyurethane composite foam cores and polymer facesheets

Abstract

This work presents an original approach by developing a new cork-incorporated polyurethane (PU) foam as a sustainable core material for sandwich structures. The novelty of the paper consists in the valorization and optimization of natural materials and the underuse of industrial products to address environmental concerns combined with high structural performance. An exhaustive experimental methodology was implemented to mechanically, physically, and thermally characterize the proposed cores and panels. Various configurations of cork particle size and percentage inclusion were considered to manufacture hybrid cores. Compression and flexural testing, thermal conductivity and ultrasonic measurements, porosity and water absorption, and SEM imaging were emphasized and discussed in the results. A two-way ANOVA-based statistical optimization was also carried out to identify the most effective formulation for a 95% confidence. The optimized cores with a 10% cork addition were subsequently assembled into PVC-skinned sandwich panels and tested under three-point bending. Outcomes in terms of load-deflection curves and failure mechanisms demonstrate a good response compared to standard foam panels with flexural strengths ranged between 4.71 and 6.61 MPa, attesting that cork-incorporated PU foam provides lightweight and high-performance solutions suitable for energy-efficient engineering applications.