4D Printing of a Fully Biobased Shape Memory Copolyester via a UV-Assisted FDM Strategy

Abstract

The emergence of 4D-printing technology provides a new opportunity for the development of shape memory polymers (SMPs) with sophisticated or individualized architectures in the most material-saving way. Fused deposition modeling (FDM) has been regarded as a feasible and facile printing technology to print thermoplastics, but the low adhesion between interlayers of the obtained objects is an unavoidable problem caused by its printing principle. Fortunately, abundant biobased chemicals with a variety of reactive groups make it easy to design ecofriendly linear SMPs with active sites, which are ready for in situ reactions during FDM printing. Herein, we developed fully biobased shape memory copolyesters (PBSe-co-PBIs) by polycondensation of dimethyl itaconate, dimethyl sebacate, and 1,4-butanediol. The flexible and crystalline PBSe may serve as a molecular switch to ensure the desirable shape memory effect (SME) of the materials, and the PBI moiety with double bonds forming cross-linking points between layers during the printing process under UV irradiation acts as net points for SMPs and enhances interlayer adhesion. The shape memory performance and the enhanced interlayer adhesion of printed materials by this strategy were verified by DMA analysis and tensile tests. Finally, a 4D-printed "Sanxingdui bronze mask" and an overheating protection cover were demonstrated, which indicated a great potential in high-temperature protection devices.

3D Printing of Green and Renewable Polymeric Materials: Toward Greener Additive Manufacturing

“…The shape memory aspect was achieved by UV curing the material as the print progressed increasing the mechanical strength of the printed parts. The resulting materials were able to achieve an ultimate tensile strength of up to 19.5 MPa due to utilizing a vertical print orientation …”

“…The resulting materials were able to achieve an ultimate tensile strength of up to 19.5 MPa due to utilizing a vertical print orientation. 31 Last, there is a growing interest in the recycling of the polymer filaments themselves. This would provide more sustainable 3D printing as well, since this approach would reduce the greenhouse gas emissions and energy requirements even for petrochemically derived polymers simply through reuse.…”

“…30 FFF materials have also been shown to exhibit shape memory behavior using a copolyester of dimethyl itaconate, dimethyl sebacate, and 1,4-butanediol produced from biobased materials. 31 The shape memory aspect was achieved by UV curing the material as the print progressed increasing the mechanical strength of the printed parts. The resulting materials were able to achieve an ultimate tensile strength of up to 19.5 MPa due to utilizing a vertical print orientation.…”

Shape Memory Polyester Scaffold Promotes Bone Defect Repair through Enhanced Osteogenic Ability and Mechanical Stability

“…The emergence of three-dimensional (3D) printing technology provides a perfect strategy to accurately mimic the customized scaffold in sophisticated 3D shapes and the porous structure. , It is worth mentioning that the 3D printing of SMPs is also called “four-dimensional (4D) printing” because their shapes could shift over time . As an emerging technology, “4D printing” revolutionized the study of intelligent materials and structures by integrating stimulus-responsive features as the fourth dimension into 3D-printed materials . This integration unlocks enormous possibilities for the utilization of SMPs and opens new avenues for research.…”

“…Among the many printing technologies, fused deposition manufacturing (FDM) could be easily implemented in a hospital and has been considered the most convenient and suitable method for thermoplastics including crystalline aliphatic polyesters PCL. , However, limited by the layer-by-layer printing process, the products constructed using FDM display serious anisotropy in mechanical properties due to the weak interaction between each layer. , Regarding the scaffold, it is a great challenge to keep the framework stable in a physiological environment. To address this thorny issue, an ultraviolet (UV)-assisted FDM strategy was developed by us to fabricate linear polyesters containing photoactive groups . The in situ photo-cross-linking of the printed object effectively solves this problem.…”