Synthesis and characterization of a cured epoxy resin with a benzoxazine monomer containing allyl groups

Abstract

Vinyl-terminated benzoxazine (VB-a), which can be polymerized through ring-opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer was then blended with epoxy resin and then concurrently thermally cured to form an epoxy/VB-a copolymer network. To understand the curing kinetics of this epoxy/VB-a copolymer, dynamic differential scanning calorimetry measurements were performed by the Kissinger and Flynn-Wall-Ozawa methods. Fourier transform infrared (FTIR) analyses revealed the presence of thermal curing reactions and hydrogen-bonding interactions of the epoxy/VB-a copolymers. Meanwhile, a significant enhancement of the ring-opening and allyl polymerizations of the epoxy was observed. For these interpenetrating polymer networks, dynamic mechanical analysis and thermogravimetric analysis results indicate that the thermal properties increased with increasing VB-a content in the epoxy/VB-a copolymers.

High-Tg, Low-Dielectric Epoxy Thermosets Derived from Methacrylate-Containing Polyimides

“…Epoxy resins are commonly cured by active hydrogen-containing compounds such as phenol novolac, bisphenol A novolac, dicyandiamide, and diamine [4][5][6][7][8][9][10][11][12][13]. However, the reaction product from active hydrogen and epoxy lead to a secondary alcohol.…”

Novel epoxy-benzoxazine water-based emulsions with reactive benzoxazine surfactants for coatings

“…However, as a consequence of lowered curing onset temperature, even broader exothermic peaks were observed. This indicates that during the curing process different reactions take place [8,14,15,17,19]. Figure 7 also shows that benzoxazine surfactants were completely cured already after first DSC runs, since no exothermic peak was observed in DSC thermograms of second runs.…”

“…&H value, on the other hand, increased with increasing concentration of epoxy groups in epoxy resin, which is confirmed by Figure 9 and results listed in Table 2, where it can be seen that Epoxy 340, which has the lowest molar weight, releases more heat during curing compared to other epoxy resins. Some epoxy-benzoxazine combinations have two exothermic peaks in their thermograms (Figure 10), which became more distinguishable with increasing benzoxazine content, because curing of an epoxybenzoxazine system is a multiple step process including more than one reaction [8,14,15,17,19]. 3.4.…”

“…Unfortunately, also copolymerization of benzoxazines with epoxy resins takes place at elevated temperatures [8,[10][11][12][13][14][15][16][17][18]. However, combining epoxy and benzoxazine resins seems a very perspective approach to design thermosets of enhanced properties, since also epoxy resins possess some excellent properties, such as good chemical resistance to solvents and good adhesion to many substrates [8,11,18,19]. One of promising applications may be an epoxy-benzoxazine coating for different substrates.…”

Preparation and characterization of a novel microcapsule-type latent curing agent for epoxy resin

“…Epoxy resins have been widely used in coatings, adhesives, insulating materials and composites because of their superior properties such as toughness, resistance to various chemicals and dielectric strength [1][2][3][4][5][6]. The superior mechanical and chemical properties of epoxy resins have close relationship with their curing processes, in which the resin with low molecular weight is transformed into polymer with infinite molecular weight and three-dimensional network structure [7][8][9][10][11][12][13].…”