Novel Biobased Non-Isocyanate Polyurethanes from Microbially Produced 7,10-Dihydroxy-8(E)-Octadecenoic Acid for Potential Packaging and Coating Applications

Abstract

In this study, a green and sustainable strategy was opted for the synthesis of a novel biobased non-isocyanate polyurethane (NIPU) or polyhydroxyurethane (PHU). NIPU or PHU was synthesized from microbially converted hydroxy fatty acid-based cyclic carbonate and diamine cross-linker. Initially, oleic acid was biotransformed into 7,10-dihydroxy-8­(E)-octadecenoic acid (DOD) using Pseudomonas aeruginosa. The cell-free approach was chosen for DOD production due to its high yield and productivity. Afterward, DOD was modified into DOD-based tricyclic carbonate by a two-step method. The prepared monomeric material was characterized using Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), and 13C NMR analyses. A series of DOD-based PHUs (DOD PHUs) were synthesized with different amine contents, and their structures were studied by FTIR and 1H NMR analyses. The morphological, mechanical, and thermal properties of DOD PHU were further analyzed. The tensile strength and elongation at break of the prepared DOD PHU were in the range of 2–6 MPa and 39–76%, respectively. The glass transition temperature of the material was in the range of 4–27 °C. Thermogravimetric analysis exhibited that thermal stability increases with the increase in amine content. The gel content was in the range of 73–100%, suggesting that the polymers are highly cross-linked. In addition, the synthesized DOD PHU displayed excellent ultraviolet and water resistance properties. The green synthesized DOD PHU depicts suitability for a wide range of applications, particularly in the coating and packaging industries.

Mechanically strong non-isocyanate polyurethane thermosets from cyclic carbonate linseed oil

“…The structures of the NIPU films became more compact due to the HB that is formed between amide N–H and CO. 30 Kim et al reported that the mechanical properties were improved with the increase in amine/cyclic carbonate molar ratio due to a large number of strong hydrogen bonds in the resulting polymer structures. 34 These results demonstrate that the properties of the NIPU polymer networks could be tailored by choosing different functionalities of CLSO, different reactant ratios and different diamine types.…”

“…The first thermal degradation stage of the NIPU films occurred at 220–320 °C, which was attributed to the decomposition of the unstable urethane bonds to alcohols, primary amines, secondary amines and CO 2 . 34 The second stage (320–460 °C) was the fastest thermal degradation process of the NIPU films, corresponding to the degradation of the unsaturated fatty acid chains of the CLSO. The final thermal degradation stage of the NIPU films occurring above 460 °C could be related to the decomposition of the residual components.…”

“…Every hydrogen bond (HB) generated an additional supramolecular network in the NIPU matrix, which extended throughout the polymer structure and acted as a bridge between the chains. 34 FTIR was a valuable tool to monitor the association and dissociation of hydrogen bonding. 36,37 When the CvO and N-H units of amides and urethanes formed hydrogen bonds, the characteristic infrared absorption frequencies shifted due to bond length changes.…”

Mechanochromic Self-Healing Materials with Good Stretchability, Shape Memory Behavior, Cyclability, and Reversibility Based on Multiple Hydrogen Bonds

“…As the temperature rose from 40 to 600 °C, three significant drops could be found from the weight loss curves of the PE-PU0 and PE-PU3 samples (Figure b). The first weight loss that appeared at 240.3–257.7 °C was assigned to the decomposition of the carbamate groups into primary or secondary amines . Afterward, the second weight loss was observed at 305.8 °C, which was ascribed to the thermal decomposition of ethyl cellulose.…”

Mechanically Robust and Chemically Recyclable Polyhydroxyurethanes from CO2-Derived Six-Membered Cyclic Carbonates

“…Aminolysis of cyclic carbonate to form polyhydroxyurethanes (PHU), one of the NIPUs, has been regarded as the most promising and competitive synthetic strategy. , Therefore, the development of PHU materials with outstanding mechanical strength, tunable properties, and adaptable performance to replace conventional PU has become a hot topic. A variety of PHU materials has been explored such as bio-based PHU, − PHU composites, , and rapid self-healing PHU materials. , The molar mass of linear PHU obtained by aminolysis range from 10 4 to 2 × 10 4 g/mol, which makes it a good choice to prepare functional materials as reactive prepolymers or chain extension of preformed polymers . As a result, less work has been carried out to tune the properties of PHU materials compared to the workload of studying the diversity of PHU materials.…”