Curing characteristics, kinetics, and thermal properties of multifunctional fluorene benzoxazines containing hydroxyl groups

Abstract

In this article, 9, 9-bis (4-aminophenyl)-2, 7-dihydroxy-fluorene (BADHF) was synthesized using methylsulfonic acid as catalyzer by direct condensation. Two kinds of novel multifunctional benzoxazine monomers containing fluorenyl groups and hydroxyl groups (MB-FH) were obtained from the chemical reaction of BADHF, salicylaldehyde, paraformaldehyde, and ethanolamine (or diethyleneglycolamine) through the adoption of o-hydroxy-benzylamine method and one-step Mannich condensation reaction method. In the traditional threestep synthesis method, the double bond reduction process took 8-12 h, but in this article, it only took 15 min. The structures of MB-FH monomers and their intermediates were characterized by Fourier transform infrared spectroscopy (FTIR), 1 H nuclear magnetic resonance (1 H NMR). The curing behaviors, curing kinetics, and thermal properties of MB-FH monomers were tested by using a dynamic rheometer, differential scanning calorimeter (DSC), FTIR, dynamic mechanical analysis (DMA), and thermogravimetric analyzer (TGA). The curing induction time can be apparently shortened by the introduction of hydroxyl groups into benzoxazine monomers, and it can catalyze the ring-opening polymerization of oxazine rings at lower temperatures, and improve the interaction of hydrogen bonds in the structure of polybenzoxazine. K E Y W O R D S crosslinking, kinetics, thermal properties, thermosets 1 | INTRODUCTION Polybenzoxazine, as a new kind of phenolic resin, possesses many excellent characteristics, for instance, the flexibility of molecular design, dimensional stability, heat resistance, flame retardancy, no generation of by-products, and low moisture absorption, etc. 1-5 Therefore, benzoxazine resin has broad application prospects in the fields of composites,

Synthesis and properties of a novel autocatalytic phthalonitrile monomer and its copolymerization with multi‐functional fluorene‐based benzoxazine monomers

“…All used chemicals were of AR grade. The two MFFB monomers [octylamine‐based ( t ‐BF‐sa‐o) and diethyleneglycolamine‐based ( t ‐BF‐sa‐dca) multi‐functional fluorene‐based benzoxazine monomers] were produced in the laboratory according to the References 36, 37.…”

The mechanochemical synthesis of environmentally benign fully biobased 4th generation benzoxazines and their polymers: mechanistic insights into the catalytic activity of latent catalysts

“…Alternatively, the introduction of active acidic functionalities, such as phenolic hydroxyls, thiols, and hydroxyethyl groups, in BZ monomers can also lower the ROP temperature. [16][17][18][19] However, the issue of the short shelf life of BZs persists. To mitigate this limitation, the incorporation of functionalities with an inherent latent catalytic effect in the phenolic and amine counterparts of BZ has been attempted.…”

Reprocessable Polybenzoxazine Thermosets with High Tgs and Mechanical Strength Retentions Using Boronic Ester Bonds as Crosslinkages

“…Benzoxazine resin, as a new class of thermosetting polymer, has gained considerable attention in recent years on account of its brilliant heat resistance, excellent flame retardance, and high hydrophobicity [ 13 , 14 , 15 ]. Recently, various dynamic covalent bonds have been introduced into polybenzoxazine networks to achieve self-healabilty or reprocessability [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”