Synthesis of a Liquid Lignin-Based Methacrylate Resin and Its Application in 3D Printing without Any Reactive Diluents

Abstract

3D printing of bio-based and renewable polymers such as lignin has gained research attention during the last few decades. We report on the synthesis and characterization of a liquid lignin-based photopolymer and its application in additive manufacturing (AM). Wheat straw soda lignin is liquified in an oxyalkylation reaction with propylene oxide under alkaline conditions and modified with methacryloyl chloride to obtain a lignin-based methacrylate resin. Ninety percent of the functional hydroxyl groups are grafted during the synthesis. The photopolymerization efficiency was evaluated by real-time-NIR-photorheology experiments with two different photoinitiators, leading to double bond conversions (DBC) of ≥80%. 3D-printing experiments of the methacrylated lignin were performed with the hot lithography technology. For the first time, a light-curable lignin derivative with a lignin content of over 30% was successfully 3D printed via vat photopolymerization without any reactive diluents, which is a significant improvement over current state-of-the-art solutions. This outstanding result is a motivating proof of concept and a promising starting point for the in-depth evaluation of bio-based precursors as an alternative to nonrenewable derivatives for 3D printing.

Type I Photoinitiator Based on Sustainable Carbon Dots

“…dental restauration. [26] The curing depth with samples comprising CD-PI was checked without deoxygenated treatment. A linear dependence existed between exposure time up to 30 min resulting in curing depth of ~25 mm.…”

Tannin-Assisted Synthesis of Nanocomposites Loaded with Silver Nanoparticles and Their Multifunctional Applications

“…As one of the traditional polymer materials, following Baekeland’s pioneering efforts in 1907, phenolic resins have gained considerable interest and have been used in a broad range of applications because of their unique properties. , Compared with the conventional nanocarrier materials, phenolic resins with versatile micro/nanostructures as an emerging carrier of Ag NPs have great application prospects and because of their simple preparation possess low cost, stable chemical structure, controllable size, large specific surface area, etc. However, limited accessible active sites and poor spatial environment for the location of Ag NPs make their application as phenolic resin nanomaterials challenging.…”

Typ‐I‐Photoinitiator auf der Basis nachhaltiger Kohlenstoffpunkte

“…B. bei der Zahnrestauration. [26] Die Aushärtungstiefe von Proben, die CD-PI enthalten, wurde ohne Entfernung von geprüft. Es bestand eine lineare Abhängigkeit von der Belichtungszeit bis zu 30 Minuten, was zu einer Aushärtungstiefe von ~25 mm führte.…”