3D printing of thermosets with diverse rheological and functional applicabilities

Abstract

Thermosets such as silicone are ubiquitous. However, existing manufacturing of thermosets involves either a prolonged manufacturing cycle (e.g., reaction injection molding), low geometric complexity (e.g., casting), or limited processable materials (e.g., frontal polymerization). Here, we report an in situ dual heating (ISDH) strategy for the rapid 3D printing of thermosets with complex structures and diverse rheological properties by incorporating direct ink writing (DIW) technique and a heating-accelerated in situ gelation mechanism. Enabled by an integrated Joule heater at the printhead, extruded thermosetting inks can quickly cure in situ, allowing for DIW of various thermosets with viscosities spanning five orders of magnitude, printed height over 100 mm, and high resolution of 50 μm. We further demonstrate DIW of a set of heterogenous thermosets using multiple functional materials and present a hybrid printing of a multilayer soft electronic circuit. Our ISDH strategy paves the way for fast manufacturing of thermosets for various emerging fields.

Robust Biobased Vitrimers and Its Application to Closed-Loop Recyclable Carbon Fiber-Reinforced Composites

“…Additionally, the crosslinking density (ρ; mol/cm 3 ) of TA/ BA 0.7 /PVA 3.0 was evaluated using eq 4 based on the DMA results (Figure 3a) (4) where R is the gas constant (8.3144598 J/mol•K), T is the absolute temperature at T g + 50 °C (414 K), and E e ′ is the storage modulus at T g + 50 °C (584 J/cm 3 ). Therefore, the crosslinking density of TA/BA 0.7 /PVA 3.0 was evaluated to be 0.056 mol/cm 3 .…”

“…1−3 To maximize the excellent properties of CFRPs, thermosetting resins are typically used as their matrix. 2 Composite materials in various industrial products, such as wind turbines, sports goods, 4 and electronic systems, are prepared using thermosetting resins as the matrix; these materials account for 15% of the total plastic consumption. 5 Because thermosetting resins form three-dimensional (3D) covalent crosslinks, they exhibit superior strength, thermal stability, and creep resistance.…”

“…Carbon–fiber-reinforced plastics (CFRPs) are used in various industrial fields, such as aerospace, automobile, and structural material development, owing to their light weight, excellent corrosion resistance, high strength, and elastic modulus. − To maximize the excellent properties of CFRPs, thermosetting resins are typically used as their matrix . Composite materials in various industrial products, such as wind turbines, sports goods, and electronic systems, are prepared using thermosetting resins as the matrix; these materials account for 15% of the total plastic consumption . Because thermosetting resins form three-dimensional (3D) covalent crosslinks, they exhibit superior strength, thermal stability, and creep resistance. , However, because the 3D covalent crosslinks are permanent and irreversible, thermosetting resins can be neither melted nor depolymerized into their original monomers; consequently, these materials cannot be recycled and reprocessed. − Therefore, end-of-life waste CFRPs and thermosetting resins are either discarded in landfills or incinerated, causing serious environmental pollution and wasting energy and resources. ,,, …”

Laser‐Assisted Direct Ink Writing for High‐Fidelity Fabrication of Elastomeric Complex Structures

“…The DSC tests could be a suitable method for the purpose. [ 20 ] The DSC stacked profiles of silicone treated with different laser pulse duty factors are shown in Figure 4e. With the increase of laser power, the decrease of exothermic peak area indicates the deepening of curing degree.…”

“…In situ, the dual heating strategy was proposed for rapid 3D printing of thermosets by combining a Joule heater with the DIW printhead to provide a high‐temperature environment. [ 20 ] Compared to range heating, which inevitably requires the heat resistance of the materials and the equipment, another widely used approach is to achieve localized heating through an infrared laser‐assisted process. However, this method was mainly researched for the annealing of silver nanowires.…”