Wu Yuchao, Fei Mingen, Chen Tingting, Li Chao, Wu Shuyi, Qiu Renhui, Liu Wendi
College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, P. R. China.
College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, P. R. China.
ACS Appl Mater Interfaces. 2021 May 19;13(19):22946-22954. doi: 10.1021/acsami.1c02513. Epub 2021 May 7.
The advent of 3D printing has led to a new era of highly customized products. Printing reprocessable thermoplastic polymers is limited to slow printing techniques such as fused deposition modeling. Photocuring 3D printing is a high-speed 3D printing technique suitable for photocurable thermosetting resins because the cross-linked 3D network could achieve rapid solid-liquid separation during printing. However, thermoplastics usually cannot be printed via photocuring 3D printers because rapid solid-liquid separation is hard to be achieved due to the diffusion/dissolution of linear molecular chains in their liquid precursor. Herein, we hypothesize that hydrogen bonds (H-bonds) between monomers may accelerate polymerization and reduce solubility of the polymer in liquid precursors to achieve rapid solid-liquid separation. Using this strategy, a series of UV-curable methacrylic and acrylic monomers was selected as inks to demonstrate the role of H-bonds in photocuring 3D printing. The hypothesis was further verified by using blended inks of -vinyl-2-pyrrolidinone (NVP) and acrylic acid (AA) via experimental and molecular dynamic simulation. Oil palm occupies the top position of plantation species in southeastern Asian forests. Palm oil (PO) has the lowest price compared with other plant oils. Thus, a PO-based vinyl monomer was selected as the raw material for 3D printing thermoplastic polymers. Various biobased thermoplastics were successfully printed from the PO-based monomer and commercial monomers. The amide structure in the PO monomer formed H-bonds with polar monomers, including NVP and AA, resulting in printed 3D objects with surprising functionalities such as high stretchability and self-healing ability.
3D打印的出现开启了一个高度定制化产品的新时代。打印可再加工的热塑性聚合物仅限于诸如熔融沉积建模等慢速打印技术。光固化3D打印是一种适用于光固化热固性树脂的高速3D打印技术，因为交联的3D网络在打印过程中可实现快速的固液分离。然而，热塑性塑料通常无法通过光固化3D打印机进行打印，因为线性分子链在其液体前驱体中的扩散/溶解使得难以实现快速固液分离。在此，我们假设单体之间的氢键（H键）可能会加速聚合反应并降低聚合物在液体前驱体中的溶解度，从而实现快速固液分离。采用这一策略，一系列可紫外光固化的甲基丙烯酸酯和丙烯酸酯单体被选作墨水，以证明氢键在光固化3D打印中的作用。通过使用N-乙烯基-2-吡咯烷酮（NVP）和丙烯酸（AA）的混合墨水，经实验和分子动力学模拟进一步验证了这一假设。油棕在东南亚森林的种植物种中占据首位。与其他植物油相比，棕榈油（PO）价格最低。因此，一种基于PO的乙烯基单体被选作3D打印热塑性聚合物的原料。从基于PO的单体和商业单体成功打印出了各种生物基热塑性塑料。PO单体中的酰胺结构与包括NVP和AA在内的极性单体形成氢键，从而得到具有诸如高拉伸性和自愈能力等惊人功能的3D打印物体。
