A truly bio-based benzoxazine derived from three natural reactants obtained under environmentally friendly conditions and its polymer properties

Abstract

The majority of the published bio-based benzoxazine research has focused almost exclusively on different phenolic and amine compounds, while the aldehyde portion of the oxazine ring remains the same.

Microporous Carbon and Carbon/Metal Composite Materials Derived from Bio-Benzoxazine-Linked Precursor for CO2 Capture and Energy Storage Applications

“…As expected, both the thermal degradation temperatures and the char yield of AP-BZ increased significantly upon increasing the thermal curing temperature from 110 to 250 °C, due to the formation of crosslinked structures with increasing crosslinking density after ROP of the oxazine ring. The poly(AP-BZ) obtained after thermal curing at 250 °C had higher thermal stability—characterized by higher values of T d5 (340 °C) and T d10 (382 °C) and a higher char yield (45 wt %)—than the previously reported BZ monomers poly(AP-f), poly(BA-a), and poly(NAR-fa) [ 25 , 26 ].…”

“…Based on the Kissinger and Ozawa methods [ 56 , 57 ], we calculated values of E a for the AP-BZ monomer of 23.93 and 8.36 kJ mol –1 , respectively, suggesting low-energy activation of the polymerization of AP-BZ. Notably, our new AP-BZ displayed values of E a much lower than those of other BZ monomers, bis-BZ monomers, and a previously prepared apigenin-based BZ (API-fa) [ 25 , 26 ]. This unique characteristic of AP-BZ during polymerization inspired us to prepare POP derivatives for application to energy storage and gas capture.…”

“…Many reviews describe how adding a catalyst, cationic species, or initiator or incorporating various functional groups (e.g., carboxylic acids, amines, phenols) into BZ resins can accelerate the rate of polymerization or decrease the polymerization temperature [ 11 ]. Many BZs derived from renewable, naturally abundant, bio-based phenols (e.g., resveratrol, bisguaiacol-F, sesamol, diphenolic acid, magnolol, eugenol, daidzein, apigenin, guaiacol, naringenin, coumarin, vanillin, sesamol, cardanol, urushiol, and guaiacol) have been easier to prepare, have displayed superior thermal properties and higher cross-linking densities, and have undergone ROP at lower temperatures when compared with those characteristics of BZ resins derived from petroleum compounds [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. For example, apigenin-, naringenin-, and daidzein-based bio-BZs have high glass transition temperatures ( T g , up to 360 °C) because they allow additional crosslinking reactions to occur from the olefinic bonds in their molecular structures, leading to highly cross-linked networks after ROP of their BZ units [ 27 , 28 , 29 ].…”

Sustainable and Ecofriendly Chemical Design of High Performance Bio-Based Thermosets for Advanced Applications

“…After an extensive literature survey, it appeared that only one study overcame this issue by substituting the paraformaldehyde with benzaldehyde. Thus, Machado et al described the solventless synthesis of so-called truly bio-based BZ monomers from sesamol, furfurylamine, and benzaldehyde (Machado et al, 2021). The corresponding polymer has high thermal stability with 5 and 10% weight-loss temperature of 317 and 332°C, respectively, char yield of 46%, and heat release capacity of 201 J/g.k.…”

Synthesis and thermal behaviour of thiophene-based oxazine-ring substituted benzoxazine monomers & polymers

“…3a and Table S1, ESI†), and revealed a short noncovalent distance and bond angle between the plane of the O-atom in the oxazine ring and aromatic ring at the 2-position [ O⋯H G –C G (2-phenyl ring) = 2.428 Å and O⋯H–C = 99.85°]. Natural Bond Orbital (NBO) analysis of PH-ta-[ 2 , 4 ]ph using theoretical calculations at the B3LYP/6-31(d,p) 11 level of theory revealed the existence of weak intramolecular noncovalent interactions between the nO (oxazine ring) → σ* (phenyl C–H G ), as depicted in Fig. 3b with second-order perturbation energy, E (2) , equal to 0.62 kcal mol −1 .…”