Current efforts for developing biobased monomers focus primarily on retrosynthetic pathways to provide direct replacements to petrochemicals. An alternate strategy includes utilizing “bioprivileged” platform intermediates to access novel monomers with properties that are not readily accessible from petroleum. Muconic acid, obtained through fermentation of sugar or lignin, has been identified as a bioprivileged compound key to the production of unsaturated diacids that can substitute for adipic acid and terephthalic acid to manufacture polyamides and polyesters with tailored functional properties. In this study, trans,trans-muconic acid (ttMA) was reacted with ethylene using Diels-Alder chemistry to produce an unsaturated cyclic dicarboxylic acid. This molecule was further co-polymerized with hexamethylenediamine and adipic acid, at 10 and 25 mol% diacid replacement. The properties of the resulting cyclo-aliphatic polyamides were analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The insertion of the cyclic diacid into Nylon’s aliphatic backbone altered its crystallinity thereby reducing its melting temperature. Additionally, the polymers exhibited an increased glass transition temperature and higher storage modulus than conventional Nylon-6,6. Next, ttMA was reacted with various vinyl-bearing groups for targeted property enhancements such as improved hydrophobicity and flame retardance. These functionalized cyclic diacids were incorporated back into the polyamide backbone to test their end-use performance. Overall, this study demonstrates the potential of bioprivileged molecules in producing novel monomers with tuneable properties.

Novel biobased cyclic diacids for polyamides with tailored functional properties

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.