Vinyl methyl oxazolidinone as reactive diluent to overcome the solubility limitations of highly polar unsaturated polyesters

• Published in: Journal of applied polymer science Vol. 141; no. 19
• Main Authors: Wylezek, Maciej, Kalinkin, Chris, Gläser, Kristin, Adermann, Torben, García Romero, Iván, D'Andola, Giovanni, Komber, Hartmut, Lorenz, Reinhard, Voit, Brigitte
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 15.05.2024; Wiley Subscription Services, Inc
• Subjects: Butanediol; crosslinking; Diols; Dynamic mechanical analysis; Molecular structure; polycondensation; Polyester resins; Polyesters; Solubility; Styrenes; Synthesis; thermosets
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.55338

Vinyl methyl oxazolidinone (VMOX®) is studied as a new reactive diluent (RD) for highly polar unsaturated polyesters (UPs). Molecules with special structure properties are extensively investigated as components for unsaturated polyester resins (UPRs) and thermosets, particularly for high‐temperature applications. Special diols with a cyclic structure like isosorbide and tricyclodecanedimethanol or special diols with side groups like 2‐methyl‐2‐propyl‐1,3‐propanediol and 2‐ethyl‐2‐butyl‐1,3‐propanediol can provide interesting properties. Bio‐based diols such as isosorbide and 1,3‐butanediol improve the sustainability profile. However, UPs based on such special diols have a higher polarity, limiting their solubility in styrene. This demands a RD, which provides adequate solubility and is suitable for high‐temperature applications. Therefore, our study compares the solubility of highly polar UPs based on special diols in styrene and VMOX®. UPs with different formulations, polarities, and Hansen parameters were synthesized and characterized. The solubility sphere of styrene was determined experimentally with the synthesized UPs. The influence of the special diols on the thermoset properties was investigated in dynamic mechanical analysis measurements. In conclusion, VMOX® as a RD enables full utilization of special diols properties due to the wide solubility window. Moreover, a new class of high‐temperature styrene‐free UP resin was developed. Highly polar unsaturated polyesters (UPs) are soluble in vinyl methyl oxazolidinone (VMOX®) and insoluble in styrene. The styrene solubility sphere with radius R0 = 12.71 was determined experimentally. Small VMOX® amount improves UPs solubility in styrene. VMOX® solubility sphere could not be determined. Thermosets based on high‐polar UPs and VMOX® achieve Tg between 187 and 207°C.