Synthesis of Bio-Based Thermoset Mixture Composed of Methacrylated Rapeseed Oil and Methacrylated Methyl Lactate: One-Pot Synthesis Using Formed Methacrylic Acid as a Continual Reactant

Abstract

Methacrylated vegetable oils are promising bio-based polymerizable precursors for potential material application in several fields, such as coating technologies or 3D printing. The reactants’ availability for their production is an enormous advantage, but the modified oils also exhibit high apparent viscosity values and poor mechanical properties. This work focuses on a way to produce oil-based polymerizable material precursors in a mixture with a viscosity modifier in a one-batch process. The required methacrylic acid for the modification of epoxidized vegetable oils can be obtained as a secondary product of the methacrylation of methyl lactate forming a polymerizable monomer along with the acid. This reaction results in a yield of over 98% of methacrylic acid. Epoxidized vegetable oil can be added into the same batch using acid for oil modification which results in the one-pot mixture of both methacrylated oil and methyl lactate. The structural verifications of products were provided via FT-IR, 1H NMR, and volumetric methods. This two-step reaction process produces a thermoset mixture with a lower apparent viscosity of 142.6 mPa·s in comparison with methacrylated oil exhibiting a value of 1790.2 mPa·s. Other physical-chemical properties of the resin mixture such as storage modulus (E′ = 1260 MPa), glass transition temperature (Tg = 50.0 °C), or polymerization activation energy (17.3 kJ/mol) are enhanced in comparison with the methacrylated vegetable oil. The synthesized one-pot mixture does not require additional methacrylic acid due to the use of the one formed in the first step of the reaction, while the eventual thermoset mixture exhibits enhanced material properties compared to the methacrylated vegetable oil itself. Precursors synthesized in this work may find their purpose in the field of coating technologies, since these applications require detailed viscosity modifications.

Designing Sustainable Polymers: Lactate Esters for 3D Printing and Upcycling

“…This is caused by an increase in the hydrophobicity with longer alkyl chains, which lowers product loss during the aqueous workup. The present reaction conditions outperform those previously reported in terms of efficiency and from a green chemistry standpoint by using a reusable catalyst. ,, …”

“…The present reaction conditions outperform those previously reported in terms of efficiency and from a green chemistry standpoint by using a reusable catalyst. 30,33,42 3D Printing of Lactate Ester-Based Formulations. The functionalized lactate esters were implemented as biobased monomers for DLP 3D printing (Figure 3).…”

“…Lactate esters are small biobased molecules that have mainly been used as green solvents, , with some further applications as additives in food and cosmetics. , They can be obtained by esterification of lactic acid, which is industrially sourced by fermenting carbohydrates with the desired alcohol. , Recently, their scope has been expanded to applications in polymer chemistry. − However, to the best of our knowledge, their application as monomers for 3D printing has not yet been reported.…”