Thermosets derived from diallyl-containing main-chain type benzoxazine polymers

Making Benzoxazine Greener and Stronger: Renewable Resource, Microwave Irradiation, Green Solvent, and Excellent Thermal Properties

“…On the basis of literature survey, 6,44−46 the ring-opening polymerization (ROP) of ortho-and para-blocked furancontaining benzoxazine takes place below 270 °C, and the exothermic peak for oxazine and allyl thermal polymerization reaction usually overlaps. 40,42,47 Therefore, the single exothermic peak during DSC heating scan in Figure 3 should be attributed to the reaction of oxazine ROP and allyl radical polymerization, which was lower than that of some previously reported bio-based benzoxazines, such as 240 °C for guaiacolbased benzoxazine 16 and 256 °C for cardanol-based benzoxazine. 5 To further understand the curing mechanism of M-fa, FT-IR spectra at different curing stages were obtained to monitor the structure evolution during the curing process.…”

“…Interestingly, only one exothermic peak centered at 218 °C was observed when the heating rate was 5 °C/min, even though the upper temperature of DSC was set to be 350 °C. On the basis of literature survey, ,− the ring-opening polymerization (ROP) of ortho- and para-blocked furan-containing benzoxazine takes place below 270 °C, and the exothermic peak for oxazine and allyl thermal polymerization reaction usually overlaps. ,, Therefore, the single exothermic peak during DSC heating scan in Figure should be attributed to the reaction of oxazine ROP and allyl radical polymerization, which was lower than that of some previously reported bio-based benzoxazines, such as 240 °C for guaiacol-based benzoxazine and 256 °C for cardanol-based benzoxazine …”

“…Recently, furfurylamine has been increasingly incorporated into benzoxazine monomers due to its naturally occurring and reactive nature. ,,− In addition, allyl in benzoxazine monomers can also be involved in the formation of polymer network. − As we know, the network structure of polybenzoxazine is crucial to its properties. In this study, M-fa monomer, with special molecular structure, not only contains furan and allyl groups but also is blocked at ortho and para positions with respect to the phenolic hydroxyl.…”

Ortho-Imide and Allyl Groups Effect on Highly Thermally Stable Polybenzoxazine/Double-Decker-Shaped Polyhedral Silsesquioxane Hybrids

“…Several strategies have been tested to enhance the thermal stability of PBZs. For example, introducing allyl or alkynyl units into the BZ monomers can enhance the cross-linking density of the 3D network structure; − with this approach, the resulting PBZs can exhibit higher glass transition temperatures, superior mechanical properties, and greater solvent resistance. Alternatively, blending with other polymers can form miscible blend systems, − or blending with inorganic nanomaterials can vary the thermal properties through decreasing chain mobility.…”

“…Recently, Ishida et al proposed another way to obtain highly thermally and mechanically stable PBZs: through thermal conversion from ortho -functionalized BZs, leading to highly thermal stable polybenzoxazoles (PBOs). − These PBOs could have formed from ortho -imide-, ortho -amide-, and ortho -amide/imide-functionalized BZs through thermal conversions at relatively high temperatures (>400 °C). − In general, the thermal stability of ortho -functionalized PBZs is better than that of PBZs formed from para -functionalized BZ monomers. The introduction of allyl units or the use of ortho -functionalized BZs can improve the thermal stability, as mentioned earlier; although these individual approaches have been investigated widely, − ,− the effects of incorporating inorganic DDSQ nanoparticles into allyl- and ortho -functionalized BZ monomers, together, remain poorly understood.…”