Chrysin-Based Bio-Benzoxazine: A Copolymerizable Green Additive for Lowering Curing Temperatures and Improving Thermal Properties of Various Thermosetting Resins

Abstract

Adding copolymerizable components into thermosetting resins is a common strategy to improve the thermal and mechanical properties of thermosets. However, it remains quite challenging to discover a universal copolymerizable additive that is applicable for various thermosetting systems. Here, the flexible molecular design of benzoxazine allows us to design a biobased benzoxazine monomer (CHR-ac) with several smart functionalities, which can copolymerize with various traditional thermosetting systems, including benzoxazine, epoxy, and bismaleimide resins. CHR-ac has been synthesized using paraformaldehyde, 3aminophenylacetylene, and natural renewable chrysin as raw materials via the Mannich condensation. Specifically, the built-in intramolecular hydrogen bonding in CHR-ac results in a low polymerization temperature while it still maintains the advantage of long shelf life. In addition, the phenolic hydroxyl and acetylene groups in CHR-ac enable it to cross-link with well-commercialized thermosetting resins and significantly enhance their performance through the formation of highly cross-linked networks. Potentially, the rationally designed biobased benzoxazine in the current work can be used as a generic additive in thermosetting resins for applications spanning from the microelectronic to the aerospace industries.

Lignin as a green and multifunctional alternative to phenol for resin synthesis

“…87,88 Thermosetting PR is mainly synthesized over alkaline catalysts under excess formaldehyde. 89,90 The synthesis mechanism of thermosetting PR is shown in Fig. 3a.…”

Research Progress of Bio‐Based Polybenzoxazine Materials

“…In addition, Li et al [77] introduced the acidic medium pyrogallol into the eugenol / octadecylamine BOZ, which can effectively reduce the ring-opening polymerization temperature; the bisphenol acid / octadecylamine PBz prepared by Ručigaj et al [78] has excellent self-healing ability and shape memory function; Thirukumaran et al [79] compounded cardanol / octadecylamine BOZ with jute fiber to prepare PBz with excellent flame retardancy and high residual carbon rate. Flame retardant, hydrophobic coating, electronic packaging [48,60,63,65,68,69] etc. At present, there are relatively few studies on the synthesis of BOZ from bio-based diamines.…”

Catalytic Role of Nanoconfinement inside MIL-125 (Ti) on the Ring-Opening Polymerization of Simple Benzoxazines

“…This unique blend of advantages positions PBzs as compelling contenders for high-performance applications. Accordingly, the recent research is predominantly focusing on synthesizing monomers from renewable resources, − designing monomers with special functionalities, − blending with other monomers or polymers, , reinforcing PBzs with a diverse range of fillers, , and synthesizing polymers with arranged hydrogen bonding. − In addition to these diverse fields in benzoxazine chemistry, the combination of benzoxazines with metal–organic frameworks (MOFs) has recently gained increased attention. MOFs originate from self-assembled metal or metal oxide nodes/clusters and organic linkers, and they are crystalline structures containing ordered nanosized pores .…”