Synthesis of cresol-based benzoxazine monomers containing allyl groups and the properties of the polymers therefrom

Authors: Tsutomu Takeichi; Koji Nakamura; Tarek Agag; Hiroyuki Muto

Source: Designed Monomers & Polymers, Volume 7, Number 6, 2004 , pp. 727-740(14)

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Abstract:

A series of monofunctional benzoxazine monomers containing allyl groups was prepared from allylamine, paraformaldehyde and various cresols. Aniline-based benzoxazine monomers without allyl groups were prepared for comparison. The structure of the novel monomers was confirmed by IR, ¹H-NMR and elemental analyses. Sublimation caused problems in the polymerization of the monomers. Thus, oligomerization was done by heating the monomers at 120°C for 5 h. DSC of the oligomers exhibited two exotherms that were attributed to the polymerization of allyl group and ring-opening polymerization of oxazine ring. Light-brown transparent polybenzoxazine films were obtained by casting the pre-formed oligomer solutions, followed by heat treatment for curing. Thermal properties of the novel polybenzoxazines were examined by softening temperature measurement and thermogravimetric analyses. The results are discussed in relation to the reactivity of ortho-, meta- and para-cresols. The effect of additional allyl functionality on the enhancement of thermal properties was also examined.

Keywords: BENZOXAZINE; OLIGOMERIZATION; DIFFERENTIAL SCANNING CALORIMETRY; SPECTROSCOPY; THERMOGRAVIMETRY

Document Type: Research article

DOI: http://dx.doi.org/10.1163/1568555042474121

Publication date: 2004-12-01