Synthesis and thermal properties of a bio‐based polybenzoxazine with curing promoter

Abstract

A fully bio‐based benzoxazine, 3‐furfuryl‐8‐methoxy‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Bzf), has been prepared using guaiacol, furfurylamine, and paraformaldehyde as raw materials. Its chemical structure has been characterized by 1H and 13C NMR, FTIR, and elemental analysis. The polymerization behavior of Bzf in the presence of methyl p‐toluenesulfonate (PTSM) has been studied by FTIR and DSC, and the thermal stability of the cured resin has been evaluated by thermogravimetric analysis. It was found that PTSM is a good promoter that serves to avoid thermal decomposition of the bio‐based monomer during the curing process at high temperature. In contrast to the situation with neat Bzf, the presence of PTSM (5 mol % for Bzf) significantly improves the polymerization behaviors, including a decrease in the polymerization temperature from 240 to 174 °C, a shortening of the time required to reach the gel point on heating at 200 °C from 47 to 20 min, and an increase in the char yield of the cured resin from 53 to 62%. Moreover, these observed experimental results on the promoting effect of PTSM are interpreted in terms of several possible mechanistic schemes, which involve a catalytic effect on the dissociation of CO bonds in both the coordination ring‐opening reaction and the rearrangement from a phenoxy structure to a phenolic structure. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Biobased Benzoxazine Derived from Daidzein and Furfurylamine: Microwave‐Assisted Synthesis and Thermal Properties Investigation

“…[52] The band at 1497 cm À1 is ar esult of the trisubstituted benzene ring. In Endos'w ork, [27] similar resultsw erea lso reported. [21,22] In order to make af urthers tructuralc onfirmation, the NMR spectra of Dz-f are shown in Figure 3.…”

“…[15] Up to now,alarge quantity of biobased benzoxazines have already been prepared from the renewable cardanol, [16,17] diphenolic acid, [18,19] phloretic acid, [20] furfurylamine, [21,22] stearylamine, [23] coumarin, [24,25] umbelliferone, [26] and more recently the lignin derivatives (guaiacol, [27][28][29][30] vanillin, [31][32][33] and eugenol [34][35][36][37][38] ). [15] Up to now,alarge quantity of biobased benzoxazines have already been prepared from the renewable cardanol, [16,17] diphenolic acid, [18,19] phloretic acid, [20] furfurylamine, [21,22] stearylamine, [23] coumarin, [24,25] umbelliferone, [26] and more recently the lignin derivatives (guaiacol, [27][28][29][30] vanillin, [31][32][33] and eugenol [34][35][36]…”

A curing system of benzoxazine with amine: reactivity, reaction mechanism and material properties

“…57,58 The ortho-position on the phenolic ring is blocked and therefore complex polymerization can be avoided. 57,58 The ortho-position on the phenolic ring is blocked and therefore complex polymerization can be avoided.…”

Latent curing systems stabilized by reaction equilibrium in homogeneous mixtures of benzoxazine and amine

“…4 and Table S3). The oxazine ring of BF showed three characteristic peaks at 940 cm −1 , 1027 cm -1 , and 1223 cm −1 , assigned to the ring symmetric and anti-symmetric stretching of the C-O-C bond3132333435. When the mixture was stored at 25 °C, the three peaks were reduced clearly in the first day, but then become almost constant.…”