Thermomechanical properties of arylamine‐based benzoxazine resins alloyed with epoxy resin

Abstract

Effects of epoxy resin on various arylamine‐based benzoxazine resins, i.e., aniline (BA‐a), m‐toluidine (BA‐mt), and 3,5‐xylidine (BA‐35x), have been investigated. Processing windows of BA‐35x, BA‐mt, and BA‐a were found to be widened with the amount of the epoxy. Gel points of benzoxazine‐epoxy resin mixtures can be predicted by an Arrhenius equation, e.g., gel time of BA‐35x and epoxy mixture at 70:30 mass ratio can be estimated by tgel = 0.7012 × 10−7 exp (10.563/T). Glass transition temperature (Tg) of BA‐a and BA‐mt alloyed with epoxy exhibited a synergistic behavior with the maximum Tg value at the benzoxazine‐epoxy composition of 80:20 mass ratio. However, in the BA‐35x and epoxy mixture, the decreasing trend in Tg from 241°C to 223°C with an addition of epoxy was observed. Furthermore, flexural strength and strain‐at‐break of those alloys were found to increase with increasing amount of the epoxy while modulus increased with the polybenzoxazine mass fraction. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Effects of benzoxazine resin on property enhancement of shape memory epoxy: A dual function of benzoxazine resin as a curing agent and a stable network segment

“…The phenolic hydroxyl groups of the ring opened the BA-a monomer then acted as an epoxy curing agent to open the epoxide ring to form the ether linkages in the copolymer networks as proposed in Figure 4b. These results are also in good agreement with the previous reports by our research group [30,36] and Kimura et al [31] using different types of epoxy resins.…”

“…More importantly, the benzoxazine resin has been shown to be able to blend with various types of resins or polymers to provide even broader spectrum of the copolymer properties. As exemplified, benzoxazine resin had been shown to be able to function as a latent curing agent for epoxy resin and, in some cases, provide synergism in thermal and mechanical properties of the obtained benzoxazine/epoxy copolymers [27,[29][30][31]. Very recently, shape memory polymers between bisphenol-A/aniline based benzoxazine resin (BA-a) and shape memory polyurethane (SMPU) have been investigated by Erden and Jana [32].…”

Characterizations of polybenzoxazine modified with isomeric biphenyltetracarboxylic dianhydrides

“…Moreover, polybenzoxazine provides some characteristics such as excellent dimension stability, high heat resistance, flame retardance and low moisture absorption as well as good dielectric properties in which cannot be found in traditional phenolic resins [6,7]. Alloying of polybenzoxazine with various other resins or polymers has been reported to economically provide a novel class of resin systems with superior performance [1,4,[8][9][10][11][12][13][14][15]. However, the major shortcoming of polybenzoxazine is its relatively high rigidity.…”

“…Alloying between benzoxazine resin and epoxy resin is considered to be a potentially effective measure to enhance thermal, mechanical properties, and flammability as well as processability of the polymers. Rimdusit et al [12] investigated effects of epoxy resin on various arylamine-based benzoxazine resins, i.e. aniline (BA-a), m-toluidine (BA-mt), and 3,5-xylidine (BA-35x) on processability, thermal, and mechanical properties of the polybenzoxazine copolymers.…”

“…Therefore, various efforts have been done to toughen polybenzoxazine such as by easily blending with more flexible monomers or polymers e.g. flexible epoxy resins [9,12], urethane elastomers [8,13], polyimides [14,15] or dianhydrides [16,17]. In recent reports, thermal and thermo-oxidative stabilities of polybenzoxazines have been substantially improved by alloying techniques [8,[15][16][17][18].…”