Novel benzoxazine monomer containing diacetylene linkage: An approach to benzoxazine thermosets with low polymerization temperature without added initiators or catalysts

Partially Bio-Based Benzoxazine Monomers Derived from Thymol: Photoluminescent Properties, Polymerization Characteristics, Hydrophobic Coating Investigations, and Anticorrosion Studies

In this work, four thymol-based benzoxazines were synthesized using four primary amines with different chain lengths, namely methylamine, ethylamine, 1-propylamine, and 1-butylamine, which are then named T-m, T-e, T-p, and T-b, respectively. The optical properties of the synthesized thymol-based benzoxazines were examined via the photoluminescent study of their solutions in acetone. The results show that all the prepared benzoxazines emitted blue light with the maximum wavelengths from 425 to 450 nm when irradiated by the excitation wavelengths from 275 to 315 nm. The maximum excitation wavelengths are found to be 275 nm. The polymerization of the thymol-based benzoxazines is triggered by heat treatments with different conditions (160, 180, and 200 °C for 1 h). According to the FTIR results, the heat-curing process introduces a presence of the OH peak, of which intensity increases as the curing temperature increases. Thermal decompositions of thymol-based benzoxazines regarding TGA analyses reveal the enhancement of thermal stability of the benzoxazines with respect to the N-substituent chain length, as significantly observed the change in the first thermal decomposition at temperature ranged from 253 to 260 °C. Synthesized benzoxazine derivatives are further employed to coat the substrate, e.g., the glass slides. The investigation of the water contact angle shows that the coating of the benzoxazines onto the surface improves the hydrophobicity of the substrate, resulting in the enlargement of the contact angle from 25.5° to 93.3°. Moreover, the anticorrosion performance of the polybenzoxazine coatings is examined using potentiodynamic polarization techniques. The results illustrate the anticorrosion efficiency of the thymol-based polybenzoxazine up to 99.99%. Both hydrophobic and electrochemical studies suggest the feasibility for employing benzoxazines in anticorrosion coating applications.

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

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.

Effect of hydrogen bonds on the polymerization of benzoxazines: influence and control

Type I –OH⋯N hydrogen bonds blocked high-degree polymerization of benzoxazines and controlling them by introducing additional hydrogen-bonds acceptors can afford high-degree polymerization.

Multivalent photo-crosslinkable coumarin-containing polybenzoxazines exhibiting enhanced thermal and hydrophobic surface properties

Mono-, bi-, and trivalent coumarin-containing benzoxazine monomers were synthesized by facile Mannich reactions of 4-methyl-7-hydroxycoumarin and paraformaldehyde with aniline, bisphenol A–NH₂, and 1,3,5-tri(4-aminobenzene).

Thermal and dielectric properties of “thiol–ene” photocured hybrid composite materials from allyl-terminated benzoxazine and SH-POSS

In the present work, allyl-terminated benzoxazine and thiol-functionalized polyhedral oligomeric silsesquioxane (SH-POSS) were synthesized and their molecular structures were confirmed by Fourier transform infrared, proton nuclear magnetic resonance (NMR), carbon-13 NMR, and silicon-29 NMR spectroscopies. The PBZ hybrid composite materials were developed through photopolymerization (ultraviolet (UV) lamp) reactions of allyl-terminated benzoxazine monomer with different weight percentages of SH-POSS (P10, P30, and P50 wt%), followed by thermal curing. The data obtained from transmission electron microscopy and X-ray diffraction analysis infer the presence of homogeneous morphology of the cured samples. Data obtained from differential scanning calorimetry, thermogravimetric analysis, UV transmittance, dielectric, and contact angle studies indicate that the dual cured P50-PBZ hybrid composite exhibits higher thermal, UV shielding, and hydrophobic behavior and lower value of dielectric constant than those of lower weight percentages of SH-POSS reinforced hybrid composites.

Thermal property of an aggregation-induced emission fluorophore that forms metal–ligand complexes with Zn(ClO4)2 of salicylaldehyde azine-functionalized polybenzoxazine

A salicylaldehyde azine-functionalized benzoxazine monomer formed zinc ion complexes not only improved the thermal properties but also facilitated ring-opening polymerization.

Bifunctional polybenzoxazine nanocomposites containing photo-crosslinkable coumarin units and pyrene units capable of dispersing single-walled carbon nanotubes

A new bifunctional benzoxazine monomer possessing both coumarin and pyrene groups for photo-crosslinking and dispersing single-walled carbon nanotubes.

Synthesis and characterization of thermally cured polytriazole polymers incorporating main or side chain benzoxazine crosslinking moieties

Effect of the position of benzoxazine cross-linker on the thermal and mechanical properties of polymers.

Azopyridine-functionalized benzoxazine with Zn(ClO4)2form high-performance polybenzoxazine stabilized through metal–ligand coordination

Azopyridine-functionalized benzoxazine (PBZ) was prepared and then blended with zinc ion through metal–ligand coordination to form a high performance polybenzoxazine after thermal curing.