Synthesis and characterisation of fluorescent polyacrylonitrile copolymers with 1,8-naphthalimide side chains
Introduction
Dyeing and bleaching of synthetic polymeric materials is important for their various practical applications [1]. The comparatively low molecular mass of the 1,8-naphthalimides dyes as well as their high photostability and intensive fluorescense, makes these dyes preferable to other types of disperse and covalently bound dyes for colouration of polymers. The introduction of unsaturated polymerising double bond into naphthalimide molecules allows the combination of the two processes, dyeing and polymer formation, and the dyes being introduced during copolymerisation with vinyl monomers forming a covalent bond in the polymer molecule. During the last years we have synthesised fluorescent polymerisable compounds, derivatives of 1,8-naphthalimide [2], [3], [4], [5], [6], [7] and investigated their ability to copolymerise with styrene, methylmethacrylate or acrylonitrile, obtaining copolymers with an intensive fluorescence [7], [8], [9], [10], [11]. On the other hand, the fluorescent 1,8-naphthalimide derivatives have been extensively studied in recent years because of their various applications. Due to their spectral properties, 1,8-naphthalimide derivatives find use as fluorescent dyes for solar energy collectors [12], organic light-emitting diodes [13], markers in molecular biology [14], in laser active media [15], [16], in medicine as antiviral compounds [17] or as analgesics [18], as well as in “guest–host” liquid-crystal systems [19], [20]. Recently the photostabilising efficiency of some 1,8-naphthalimide chromophores in polymer matrices has been investigated [21], [22].
In this work we have investigated the radical copolymerisation of five new fluorescent 4-alyllamino-N-(phenyl)-1,8-naphthalimides with acrylonitrile in N,N-dimethilformamide solution, yielding coloured and intensive fluorescent polyacrylonitrile and studied some of their properties. It was of interest also to investigate the photostability of the coloured polyacrylonitrile.
Section snippets
Materials
Acrylonitrile (AN) (Fluka b.p. 75–77°C) was redestilled and dried. Dibenzoylperoxide (DBP) (Fluka 99.6%) was recrystalized from chloroform. Nitrogen (99.99%) was dry. N,N-Dimethylformamide (DMF) (Merck) for synthesis and for spectroscopy grade were used. Dyes were synthesized and purified by a method described previously [23].
The structure of the monomeric dyes is shown in the general formula presented in Scheme 1.
Kinetics of the polymerisation
The radical copolymerisation of the unsaturated naphthalimide dyes 1–5 with AN
Polymerisation of acrylonitrile
The solution process is generally used to prepare PAN polymers suitable for direct wet- or dry-fibre spinning. DMF is one of the best solvents for PAN and is used extensively. The copolymerisation of AN with the dyes was investigated kinetically. The polymerisation reactions involving dyes 1–5 with AN were conducted in sealed vials using dry degassed DMF as the solvent and benzoyl peroxide as initiator. The yields for the poly(AN-co-dye) were 55–69 and 80 wt.% for PAN at 70°C. On the basis of
Conclusion
In this paper, we presented the results of photophysical investigation of five new 1,8-naphthalimide dyes havind an allylic group in position-4 of the naphthalimide molecule and their copolymers with acrylonitrile. The monomeric 1,8-naphthalimide dyes, participated actively in copolymerisation, and 0.70–0.88% were covalently bound in the polymer chain. It was found that no change in the chemical structure of the naphthalimide derivatives occurred during polymerisation. The monomeric dyes and
References (33)
- et al.
Dyes and Pigments
(1993) - et al.
Dyes and Pigments
(1995) - et al.
Dyes and Pigments
(1997) - et al.
J Lumines
(1996) - et al.
Biorganic and Med Chem Lett.
(1993) - et al.
Displays
(1992) - et al.
J Photochem Photobiol, A:Chem.
(1998) - et al.
Polym Degrad Stab
(1999) Dyes and Pigments
(1998)- et al.
Dyes and Pigments
(1999)
Tetrahedron Letters
Polym. Int.
Dyes and Pigments
Dyes and Pigments
J. Polym. Sci. Polym. Chem.
Angew Makromol Chem.
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