V-photopolymerization 3D printing creates super strong “elastic foam”

Figure 1 shows the research ideas and experimental results of preparing high-performance foam materials by photocuring 3D printing technology. The research team developed a foamable resin system suitable for photocuring 3D printing by introducing a special polyurethane methacrylate (PUB) as the main component and combining thermally expandable microspheres (TEMs) as a foaming agent. In the experiment, by adjusting the content of PUB and the ratio of TEMs, the balance between high-precision printing and controllable foaming was successfully achieved. The results showed that this resin system has high precision and high success rate in the printing process, and the foamed foam material has excellent mechanical properties, such as tensile strain of up to 650% and density of 0.25 g/cm³. In addition, by changing the ratio of PUB to monomer, the density and mechanical properties of the foam can be adjusted to meet different application requirements. This study solves the problem of the difficulty in balancing precision and foaming performance faced by traditional photocuring 3D printing technology in preparing foam materials, and provides a new method for customized manufacturing of high-performance foam materials. 

Figure 2 shows the experimental results and performance verification of high-performance foam materials prepared by photocuring 3D printing technology. In the experiment, the researchers first tested the accuracy and foaming performance of photocurable resins with different formulations during 3D printing. The results showed that the resin system using PUB and IBOMA as the main components, combined with TEMs as a foaming agent, can achieve high-precision printing and uniform volume expansion after heating. After heat treatment, the printed samples showed excellent mechanical properties, such as tensile strain of up to 650% and density of 0.25 g/cm³. In addition, the experiment also observed the microstructure of the foam by scanning electron microscopy (SEM), and found that it had a closed-cell structure, which could not be achieved by traditional etching or emulsification methods. By simulating the foaming process through finite element analysis (FEA), the researchers were able to accurately predict the expansion behavior and dimensional changes of the foam. Finally, the researchers applied this 3D printed foam to the manufacture of shoe midsoles, verifying its potential in practical industrial applications and proving that this foam material not only has excellent mechanical properties, but can also be seamlessly integrated with existing manufacturing processes. 

Figure 3 shows the study of the mechanical properties of foam materials prepared by photocuring 3D printing technology. In the experiment, the researchers prepared foam samples with different densities and mechanical properties by changing the type and content of monomers in the photocurable resin, and performed compression and tensile tests on them. The results showed that the compressive strength and tensile strength of the foam material increased significantly with the increase of density, and at high density, it showed mechanical properties comparable to or even higher than those of commercial polyurethane foam. In particular, the IBOMA30 series samples have a compressive strength of 22 MPa at a density of 0.4 g/cm³, which is much higher than other 3D printed foam materials. In addition, by adjusting the type and content of monomers, performance adjustment from high rigidity to high toughness can be achieved. The experiment also found that the use of amine chain extenders with different functions (such as diamines and triamines) can significantly affect the crosslinking density of the polymer chain and the degree of entanglement of the molecular chain, thereby adjusting the mechanical properties of the foam. For example, the samples using triamine chain extenders showed higher crosslinking density and strength, while the samples using diamine chain extenders had better flexibility and ductility. These results show that by precisely controlling the composition and post-processing conditions of the photocurable resin, the mechanical properties of 3D printed foam materials can be flexibly adjusted to meet the needs of different application scenarios.

Figure 4 shows the performance and potential of high-performance foam materials prepared by photocuring 3D printing technology in practical applications. In the experiment, the researchers used an LCD photocuring 3D printer to manufacture foam components with different lattice structures and tested their performance in weight reduction, energy absorption and cushioning protection. The results show that by optimizing the lattice structure, 3D printed foam can achieve an extremely high strength-to-weight ratio at an extremely low density (such as 0.05 g/cm³), for example, it can withstand a load of 625 times its own weight, and at a higher density (such as 0.08 g/cm³), it can withstand the weight of an adult (75 kg) without deformation. In addition, the 3D printed foam performs well in energy absorption, and the absorbed compression energy is increased by more than 10 times compared with the unfoamed lattice structure. In the buffer protection experiment, the 3D printed foam can effectively protect the glass from impact damage, while the unprotected glass shatters under the same conditions. These results show that 3D printed foam not only has excellent mechanical properties and energy absorption capacity, but also has good shape adaptability and thermal recovery properties, which makes it have broad application prospects in the field of lightweight structural materials and buffer protection.