Thermal latent and Low-Temperature polymerization of a Bio-Benzoxazine resin from natural renewable chrysin and furfurylamine

Competitive Study of Novel Triptycene-Containing Benzoxazine Monomers and a Thermoresponsive Linear Main Chain-Type Benzoxazine Copolymer: Synthesis, Polymerization, and Thermal Properties of Their Thermosets

“…Moreover, the characteristic oxazine ring-related mode band observed in both TB-a and TB-fa spectra at 914 and 925 cm –1 , respectively, further support a successful synthesis of the monomers . In the case of TB-fa , the band at 753 cm –1 is assigned to the C–H out-of-plane in-phase wagging deformation, characteristic of the furan rings …”

“…Additionally, the furanic C–H out-of-plane in-phase wagging deformation at 753 cm –1 distinctive of the furan rings on the TB-fa partially decreased upon heating. This evidences additional cross-linking reactions involving the furan groups …”

“…32 In the case of TB-fa, the band at 753 cm −1 is assigned to the C−H out-of-plane in-phase wagging deformation, characteristic of the furan rings. 33 Figure 1b shows the 1 H NMR spectra of TB-a and TB-fa. As shown in the figure, two sets of characteristic peaks related to the two methylene groups forming the oxazine rings, namely, Ar−CH 2 −N and N−CH 2 −O, appear at 4.49 and 5.43 ppm and 3.78 and 4.84 ppm for TB-a and TB-fa, respectively.…”

“…This evidences additional cross-linking reactions involving the furan groups. 33 The thermally activated polymerization behavior of triptycene-based dioxazine benzoxazine monomers was also studied by DSC. Thermograms are shown in Figure 3c.…”

Photothermal polymerization of benzoxazines

“…17 On the one hand, we and others have investigated the use of initiators and catalysts for this purposee.g., Brønsted 18,19 and Lewis acids 20,[21][22][23][24] which can be either added as separate components to the polymerization mixture [18][19][20][21][22][23][24] or directly incorporated into the Bz monomers in a latent state. [25][26][27][28] However, only moderate T p reduction has been accomplished in this way for conventional monofunctional benzoxazines, although the introduction of additional functionalities may further lower the onset reaction temperature. 20,[29][30][31] Alternatively, Bz photopolymerization at room temperature has been explored, though with limited results.…”