Review on the Accelerated and Low-Temperature Polymerization of Benzoxazine Resins: Addition Polymerizable Sustainable Polymers

Abstract

Due to their outstanding and versatile properties, polybenzoxazines have quickly occupied a great niche of applications. Developing the ability to polymerize benzoxazine resin at lower temperatures than the current capability is essential in taking advantage of these exceptional properties and remains to be most challenging subject in the field. The current review is classified into several parts to achieve this goal. In this review, fundamentals on the synthesis and evolution of structure, which led to classification of PBz in different generations, are discussed. Classifications of PBzs are defined depending on building block as well as how structure is evolved and property obtained. Progress on the utility of biobased feedstocks from various bio-/waste-mass is also discussed and compared, wherever possible. The second part of review discusses the probable polymerization mechanism proposed for the ring-opening reactions. This is complementary to the third section, where the effect of catalysts/initiators has on triggering polymerization at low temperature is discussed extensively. The role of additional functionalities in influencing the temperature of polymerization is also discussed. There has been a shift in paradigm beyond the lowering of ring-opening polymerization (ROP) temperature and other areas of interest, such as adaptation of molecular functionality with simultaneous improvement of properties.

Novel Combination of Vinyl Benzoxazine and Its Copolymerizable Diluent with Outstanding Processability for Preparing a Bio-Based Thermoset

“…As a new type of thermosetting resin, polybenzoxazine has attracted worldwide attention in the past 30 years owing to its prominent performances in terms of not only thermal and mechanical properties − but also flexibility of molecular design, − low dielectric constant, − very low surface free energy without using fluorine atoms, and excellent flame retardancy. − Unfortunately, applications of benzoxazine have encountered processing problems because most benzoxazine monomers are solid at room temperature and their melting temperatures are generally higher than 90 °C. − Until now, poor processability of benzoxazine monomers is still the key barrier that limits the development of polybenzoxazine resin.…”

Metal Ion-Catalyzed Low-Temperature Curing of Urushiol-Based Polybenzoxazine

“…However, the curing temperature of most benzoxazine precursors is high (i.e., over 180°C), which greatly limits the application of polybenzoxazine resins. Much efforts have been devoted to reducing the curing temperature via intramolecular interaction [modification of monomer structures by electron-donating or -withdrawing groups, designing of monomer structure to influence the intermolecular packing (rigid groups)] ( Xu et al, 2015 ; Zhang et al, 2019c ; Zhu et al, 2020b ) or intermolecular interaction cationic initiators including ordinary acids, thiols or elemental sulfur, brønsted acids; catalysts including Lewis acids, amines, latent catalysts, and nanomaterials) ( Wang and Ishida 1999 ; Zhu et al, 2020a ; Chen et al, 2021a ; Liu et al, 2021 ; Lochab et al, 2021 ; Yan et al, 2021 ). Among these approaches, the introduction of Lewis acid is the most convenient and versatile one.…”

Adhesive Films Based on Benzoxazine Resins and the Photoreactive Epoxyacrylate Copolymer

“…Polybenzoxazines have outstanding properties, such as high glass transition temperature, high thermal stability, low water absorption, and excellent mechanical performance [ 10 , 11 , 12 ]. Therefore, they have a huge research and industrial application potential for various purposes, e.g., as components of self-healing systems (smart materials) [ 13 ]; as materials for space radiation shields [ 4 ]; as materials for aerospace application [ 14 ]; and as coatings, sealants and adhesives and others [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”