The combination of flexibility and elasticity makes elastomers essential in a wide range of industries, including automobiles, construction, and consumer goods. In addition, they are becoming increasingly attractive in emerging fields such as microfluidics, soft robots, wearable electronics, and medical devices. Having sufficient mechanical strength is a prerequisite for any application. Therefore, resolving the seemingly contradictory attributes between softness and strength has always been an eternal pursuit. Natural spider silk has extraordinary strength, providing a constant source of inspiration for designing and synthesizing soft materials. Although its unique superstructure is difficult to replicate, the broader principles of designing layered structures provide useful tips for designing elastic materials with high mechanical strength. However, the above design principles cannot be directly applied to digital light processing (DLP) 3D printing based on photopolymerization. DLP printing needs fast light curing to achieve the necessary fast gel. Therefore, photo resins usually contain a considerable amount of multifunctional acrylic or methyl acrylic esters, which severely limits the freedom of molecular design. In addition, rapid curing can lead to uneven network formation and residual stress, which is also detrimental to mechanical properties. The potential for large-scale production of 3D printing is hindered by its low manufacturing efficiency (printing speed) and insufficient product quality (mechanical performance). The latest progress in ultra fast 3D printing of photopolymers has alleviated the issue of manufacturing efficiency, but the mechanical properties of typical printed polymers still lag far behind traditional processing techniques.

Recently, Professor Xie Tao and Associate Researcher Wu Jingjun's team from the School of Chemical Engineering and Bioengineering at Zhejiang University published an article titled "3D printable elastomers with exceptional strength and toughness" in Nature. The study reported a 3D photo printed resin chemistry that produced elastomers with a tensile strength of 94.6 MPa and a toughness of 310.4 MJ m-3, far exceeding any 3D printed elastomer. Mechanically speaking, this is achieved by printing dynamic covalent bonds in polymers, allowing for network topology reconfiguration and facilitating the formation of hierarchical hydrogen bonds (especially amide hydrogen bonds), microphase separation, and interpenetrating structures, thereby synergistically promoting excellent mechanical properties. This work provides a brighter future for large-scale manufacturing using 3D printing.

Figure 1: Chemical Design of 3D Photoprinted Elastomers ©  2024 Springer Nature

Figure 2. Mechanical properties of elastomers and their strengthening and toughening mechanisms ©  2024 Springer Nature

Figure 3. Elasticity and mechanical properties of elastomers ©  2024 Springer Nature

Figure 4: Strong and tough elastomers printed by DLP ©  2024 Springer Nature

The ability to 3D print super strong and ultra tough materials in this work extends its range of use under extremely harsh conditions, far beyond the two examples presented in the article. In addition, the printing precursor in this work was synthesized using readily available reagents in simple steps, ensuring its low cost. Although there are other established principles for designing polymers with superior mechanical properties, it is challenging to directly apply them to 3D printing because of the strict requirements for photo printing, including rapid gel under light and sufficient container life during printing and storage. Nevertheless, they provide useful insights for the future development of alternative high-performance 3D printing materials. Overall, the study suggests that 3D printing does not necessarily compromise mechanical performance, which clears a major obstacle for its future commercial implementation.

SAT NANO is a best supplier of metal powder and alloy powder for 3D printing, we also can supply 3D service, if you have any enquiry, please feel free to contact us at admin@satnano.com