Phenolic materials via ring‐opening polymerization of benzoxazines: Effect of molecular structure on mechanical and dynamic mechanical properties

Abstract

A series of benzoxazine compounds have been prepared from different bifunctional phenols and primary amines and the molecular compositions of the precursors are characterized by nuclear magnetic resonance, Fourier transform infrared, and size exclusion chromatography. It has been demonstrated that by design of the molecular structures of the benzoxazine precursors, therefore by tailoring of the network molecular architectures, new phenolic materials with superior mechanical and thermal properties, and ease‐of‐processing characteristics can be obtained. The characteristics of dynamic mechanical spectra of the phenolic materials are studied and related to their structural features. © 1994 John Wiley & Sons, Inc.

Synthesis and characterization of benzoxazine monomers from rosin and their thermal polymerization

“…The onset polymerization temperatures of Bra-1 and Bra-2 are 182 and 183°C, which are comparable to the polymerization temperatures of other benzoxazine monomers. [1][2][3] As it can be seen in Figure 5, Bra-1 and Bra-2 exhibited an exothermic peak centered at 228 and 232°C, respectively. As mentioned earlier, the polymerization temperatures of both Bra-1 and Bra-2 were 182 and 183°C, respectively.…”

“…It suggested that the ring opening reaction of benzoxazine had occurred in both Bra-1 and Bra-2 when the temperature increased to enough. [2,3] Figure 5 shows the DSC thermograms of Bra-1 and Bra-2 with the results summarized in Table 2. For Bra-1, there is a broad exotherm at around 125°C, which may be attributed to the reaction of double bond on the monomer.…”

“…Except that the peaks for imide at 1382, 1706, and 1754 cm À1 as well as in the spectrum of MPAIP, the characteristic adsorption bands of benzoxazine for both Bra-1 and Bra-2 appeared at 937 cm À1 . [2,3] Furthermore, the bands at around 1240, 1030, and 373 cm À1 were assigned to asymmetric stretching of C-O-C and wagging of CH 2, respectively, while the band at around 1450 cm À1 was assigned to multisubstituted benzene ring. Figure 3 shows the 1 H NMR spectra of MPAIP, Bra-1, and Bra-2, respectively.…”

“…Polybenzoxazine is a novel class of polymeric materials and it can be used as high-performance resins because of its excellent properties, such as nearly zero shrinkage upon curing, low moisture absorption, limited byproduct release upon curing, and good thermal stability. [1][2][3] The benzoxazine chemistry synthesis offers a wide range of molecular design flexibility on benzoxazine monomers, which are often synthesized from primary amine, formaldehyde, and petroleum-based phenolic compound. [4][5][6][7][8] So far, several research groups have reported the synthesis of cardanol-based benzoxazine monomers from cardanol to replace part of the petroleum-based phenolic compound.…”

Synthesis and Characterization of Substituted Bisbenzoxazine as Potent Antimicrobial Agent

“…These benzoxazines were synthesized from monophenols, monoamines, and formaldehyde, but they could not form polymers with high molecular weight. After benzoxazines based on bisphenol-A were synthesized [5,6], a series of bifunctional benzoxazines have been prepared from bisphenols (or monophenols), monoamines (or diamines), and formaldehyde [7][8][9][10][11][12][13][14][15]. The bifunctional benzoxazines can form into polybenzoxazines with high molecular weight via thermally activated ring-opening polymerization reaction [16][17][18][19], and the resultant polybenzoxazines possess excellent properties, such as relatively high glass transition temperature, superior mechanical properties, excellent electrical insulation properties, low moisture absorption, high thermal stability, high char yields, and low flammability.…”