This work investigates a novel concept of sandwich panel composed of discarded polypropylene (PP) bottle caps as circular honeycomb core and skins made with a hybrid glass fibre/silica composite. A full factorial design (DoE) is carried out to identify the effects of the core packing system and the inclusion of silica particles in the composite skins, on the flexural properties of the sandwich panels. Finite element analysis validated by the experimental results is used to investigate and predict the failure mechanisms of these sandwich structures. The DoE reveals that the hexagonal packing of PP bottle caps with the presence of silica in both skins lead to increased mechanical properties, such as core shear stress (0.79 MPa), facing stress (42.56 MPa) and flexural modulus (1589.21 MPa), especially when compared to the orthotropic packing with silica only on the bottom skin which obtained a lower performance of 21.01%, 11.41% and 17.22% for core shear stress, facing stress and flexural modulus, respectively. The findings reveal an alternative upcycling route for discarded polypropylene caps.

这项工作研究了夹心板的新概念，该夹心板由废弃的聚丙烯 (PP) 瓶盖作为圆形蜂窝芯和由混合玻璃纤维/二氧化硅复合材料制成的表皮组成。进行了全因子设计 (DoE) 以确定核心填充系统和复合材料表皮中包含的二氧化硅颗粒对夹芯板弯曲性能的影响。通过实验结果验证的有限元分析用于研究和预测这些夹层结构的失效机制。DoE 表明，PP 瓶盖的六边形填料在两个表皮中都存在二氧化硅，导致机械性能增加，例如核心剪切应力 (0.79 MPa)、面应力 (42.56 MPa) 和弯曲模量 (1589.21 MPa) 特别是与仅在底部表层上使用二氧化硅的正交各向异性填料相比，其芯部剪切应力、面应力和弯曲模量的性能分别为 21.01%、11.41% 和 17.22%。研究结果揭示了废弃聚丙烯瓶盖的另一种升级回收途径。