Intrinsically flame-retardant vanillin-based PU networks with self-healing and reprocessing performances

A Biobased Epoxy Vitrimer with Dual Relaxation Mechanism: A Promising Material for Renewable, Reusable, and Recyclable Adhesives and Composites

“…The first approach for obtaining the Cyst-BVGE was synthesizing the imine derivative of vanillin with cystamine (free base) and consequent glycidylation with an excess of epichlorohydrin. The imine derivative of vanillin with cystamine was already described in the literature as a curing agent for diisocyanate monomers . Although the first step of the imine formation was achieved in good yield, the second step for the glycidyl ether incorporation was unsuccessful due to the partial hydrolysis of the imine bond and the formation of species from the ring opening of the epoxide, which was observed in the 1 H NMR spectrum (not shown).…”

Simultaneously Enhancing Mechanical Strength, Toughness, and Fire Retardancy of Biobased Polyurethane by Regulating Soft/Hard Segments and Crystallization Behavior

“…Polyurethanes (PUs) are usually synthesized from polyols and isocyanates through an addition polymerization reaction under suitable catalysts and the appropriate ratio. , The wide selectivity of raw materials and highly adjustable microstructure make polyurethanes rich in variety, and they can be used in various industries. , However, the traditional petrochemical feedstock makes it difficult to degrade and recycle polyurethane products after they have been discarded. , Biomass resources have been gradually receiving attention, and the production of polyurethane materials from biobased materials has become a hot topic . To reduce the consumption of petroleum resources, a variety of biomass materials, such as lignin (and its derivatives, such as vanillin, eugenol, etc.…”

“…In contrast, inherently flame-retardant polymers can be obtained through chemical reactions by introducing flame-retardant elements into the polymer chains without adding other flame retardants, making them have good flame retardancy and excellent mechanical properties. , Hu et al synthesized polyurethane materials with excellent reprocessability and fire resistance by grafting DOPO with vanillin and hexamethylene diisocyanate (HDI) trimer. The fabricated polyurethane material was shown to have a 30% LOI value and a UL-94 V-0 rating …”

“…Hu et al prepared flame-retarding vanillin-based polyurethane materials with dynamic imine and disulfide bonds, which exhibited excellent flame retardancy, self-healing properites, and reprocessability. However, the overall mechanical properties of the flame-retarding vanillin-based PU networks were still poor after the addition of 10% flame-retardant monomer vanillin-based polyol with the flame-retardant group . Xing et al synthesized a degradable and high-strength polyurethane elastomer by a two-step method.…”

Atom-Economic Synthesis of Phosphorus-Containing Biobased Aromatic Diol for Flame-Retardant Robust Polyurethane

“…In this context, a more optimal way to develop biobased flame-retardant polyols is based on the depolymerization products of lignin because they not only retain the aromatic rings of lignin but also possess much simpler and more precise chemical structures than lignin. Vanillin is the most productive derivate of lignin and has been widely used to synthesize aromatic polymerizable monomers for polyesters, epoxy resins, benzoxazine resins, PUs, , and polycarbonates, by taking advantage of the rich chemical diversity of its phenolic hydroxyl group and aldehyde groups. , Modifying the aldehyde groups through a condensation reaction is a commonly used strategy, , but the obtained PUs are degradable, , especially under acidic conditions, bringing about a negative effect on the mechanical properties and chemical resistance of PUs. It is believed that the use of atom-economic reactions, such as the Aldol reaction and Tishchenko reaction, , for the upgrading of vanillin by taking structural advantage of the aldehyde group not only provides a series of robust polymerizable monomers but also endows significant greenness in the emerging technologies for the preparation of biobased synthetic polymers.…”