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Three-dimensional-printed silicone rubber foams, with their designable and highly ordered pore structures, have shown exceptional potential for engineering applications, particularly in areas requiring energy absorption and cushioning. However, optimizing the mechanical properties of these foams through structural design remains a significant challenge. This study addresses this challenge by formulating the research question: How do different 3D-printed topologies and printing parameters affect the mechanical properties of silicone rubber foams, and how can we design a novel topological structure? To answer this, we explored the mechanical behavior of two common structures–simple cubic (SC) and face-centered tetragonal (FCT)–by varying printing parameters such as filament spacing, filament diameter, and layer height. Furthermore, we proposed a novel two-level 3D-printed structure, combining SC and FCT configurations to enhance performance. The results demonstrated that the two-level SC-SC structure exhibited a specific energy absorption of 8.2 to 21.0 times greater than the SC structure and 2.3 to 7.2 times greater than the FCT structure. In conclusion, this study provides new insights into the design of 3D-printed silicone rubber foams, offering a promising approach to developing advanced cushioning materials with superior energy absorption capabilities. [ABSTRACT FROM AUTHOR]

Abstract Boron carbide (B 4 C) is an important type of neutron radiation shielding material with relatively high efficiency due to the high content of 10B element. Incorporation of B 4 C particles into polymer to prepare high-performance neutron radiation shielding material has become more and more important for the safe operation of nuclear power in the defense industry and nuclear power plant. The polyimide/B 4 C composite films with different micro-sized B 4 C contents were successfully prepared by in-situ polymerization. Silane coupling agent KH550 was employed to functionalize B 4 C particles to improve the dispersion of B 4 C particles in the polyimide matrix with strengthened interfacial interaction. As shown that the micro-sized B 4 C functional particles can be well dispersed in the BPDA/ODA polyimide matrix. With the B 4 C content increase, thermal stability of the polyimide/B 4 C composite films can be significantly improved, even mechanical properties partly declined. Meanwhile, the polyimide/B 4 C composite films exhibit good thermal neutron radiation shielding properties. The neutron permeability I/I 0 changes exponentially with the change of B 4 C content. When the B 4 C content is increased to 30 wt%, the polyimide/B 4 C composite films show optimum properties combination with thermal decomposition temperature (T d 10) of 622 °C, neutron permeability (I/I 0) of 0.24 (800 μm in thickness), and tensile strength of 406 MPa. The composite thus shows great potential for use in applications which require materials with high thermal stability and neutron radiation shielding ability, such as fusion reactor system and nuclear waste disposal. [ABSTRACT FROM AUTHOR]