Lactone monomers obtained by enzyme catalysis and their use in reversible thermoresponsive networks

Abstract

The cover image by Per-Olof Syrén and colleagues shows a green route to new star-shaped polymeric materials that can reconstruct themselves by means of Diels-Alder chemistry when stimulated by heat. The image shows how enzyme catalysis successfully afforded two key reaction steps. In addition, the image reveals the conversion of bulky bicyclic ketone to its corresponding activated lactone monomer, as well as end-capping of the chemically synthesized polymer with the renewable building block furoic acid.Volume 137, Number 18 was mailed the week of February 3, 2020.ARTICLES 48608 Hydrophobic-associated polymer-based laponite nanolayered silicate composite as filtrate reducer for water-based drilling fluid at high temperature

Turning natural δ-lactones to thermodynamically stable polymers with triggered recyclability

“…Many of the naturally occurring lactones are five-(γ) or six-membered (δ) rings, and have traditionally been utilized by the food-and fragrance industry. Lately, the bio-derived natural lactones have received academic attention as monomers for ROP, [7][8][9][10][11] but so far, they are not utilized commercially by the polymer industry.…”

Prospects of Using Biocatalysis for the Synthesis and Modification of Polymers

“…The resulting lactone can be subjected to enzymatic polymerization or polymerized chemically. The beneficial application of Baeyer–Villiger monooxygenases was demonstrated in the preparation of lactones from terpene derivatives, where the use of the classical approach with hydrogen peroxide would be impossible due to the formation of a significant amount of by-products [ 71 , 73 ]. The limiting factor when using this type of monooxygenases is the need to regenerate the coenzyme NAD(P)H. To solve this problem, NAD(P)H cyclic regeneration systems based on alcohol dehydrogenase or glucose oxidase with appropriate substrates were used together with monooxygenase [ 70 , 72 ].…”

“…Recent work demonstrated a very interesting scheme for the chemoenzymatic preparation of thermosensitive polymers based on star-like polyesters [ 73 ]. The described method included biocatalytic synthesis of monomeric lactone followed by its chemical copolymerization with a previously obtained star-like polycaprolactone, biocatalytic modification of the copolymer and, finally, the chemical formation of crosslinks, which have the property of breaking down on heating and forming on cooling ( Figure 17 ).…”

“…Thermoresponsive networks were generated via the reaction with 1,1’-(methylenedi-4,1-phenylene)-bis-maleimide (BMI) by Diels–Alder (DA) chemistry. The Diels–Alder cycloaddition reaction is reversible with temperature changes; thus, the bonding/debonding state of the designed gels can be modulated in response to a specific thermal treatment [ 73 ].…”