Studies on the thermal polymerization of substituted benzoxazine monomers: Electronic effects

Abstract

To evaluate the influence of the electronic effects on the polymerization temperature, we looked at several 3-phenyl-3,4-dihydro-2-H-1,3-benzoxazine monomers with electron-withdrawing or electron-donating groups in the 6 and 4 0 positions. The monomers were synthesized and characterized using different synthetic methods to achieve the best possible results. The thermal polymerization of these benzoxazine monomers was analyzed by differential scanning calorimetry, and the polymerization behavior and the polymer characteristics were related to the electronic character of the substituent and the polymerization mechanism. V

Studies on thermal and flame retardant behaviour of mixtures of bis(m-aminophenyl)methylphosphine oxide based benzoxazine and glycidylether or benzoxazine of Bisphenol A

“…However, in an effort to minimize the generation of oligomers, the synthesis of Bz-BAMPO [10] was conducted by a different pathway, preventing the direct reaction between diamine and paraformaldehyde, using a three-step synthesis [19], according the procedure presented in Scheme 1. In the first step, 2-hydroxybenzaldehyde was reacted with BAMPO.…”

Fatty acid-derived α,ω-bis-benzoxazines through hydrosilylation; curing and thermoset properties

“…In addition to the melting endotherm, all benzoxazine monomers present a relatively sharp exothermic peak between 250 and 280°C which is characteristic for the curing process of conventional non-activated benzoxazines [34].…”

“…Formation of oligomers, which reduces yield, is favoured mostly by water, polar solvents and high temperatures [1,28,32]. One way to minimize their formation consist of using paraformaldehyde and triazine derivatives in bulk conditions or with the help of low polarity solvents like toluene [32][33][34].…”

Synthesis and characterization of novel benzoxazines containing nitrile and allyl groups and their polymers

“…This can be ascribed to the existence of electron-withdrawing nitrile groups, which lead to a more acidic phenol species. Therefore, a stronger catalytic effect takes place [15].…”

“…The reason to choose nitrile and allyl groups is because recent research results reveal these two groups can greatly improve the glass transition temperature and thermal stability. Nitrile group also has electron-withdrawing effect and can decrease the polymerization temperature of the monomers [15]. In addition, all used raw materials are inexpensive and commercial.…”