FLAME RETARDANT POLYESTERS FROM RENEWABLE RESOURCES VIA ADMET

Polyesters are widely used for textile fibers, technical fibers, films, bottles or as a finish on high-quality wood products. The demand of polyesters in 2006 is an estimated 35 million tons and will grow annually by 9%.[1] Due to environmental concerns much work is devoted to the industrial use of products from renewable resources, and for this reason the development of polymeric materials, such as polyesters, from renewable resources has attracted much attention.[2] On the other hand, many kinds of flame retardants (FRs) have been tested to improve the flame retardancy of polyesters and have been applied to commercial products. Among these, phosphorous FR and halogenated FR are the most common. However, many kinds of halogenated FR, especially brominated FR, are restricted in many countries due to the formation of dioxin under combustion. Therefore most of the inherent FR polyesters are now produced using phosphorous FR by blending and/or copolymerizing with flame retardants. However, to obtain efficient flame retardancy by blending, high amounts of the flame retardant agent must be added and usually the polymer properties are affected. Also, when a blended fiber is washed, the blended flame retardants migrate to the fiber surface, leading to decreased flame retardancy and increased danger for the customers. Because of these problems, the copolymerizing method is becoming more common.
Acyclic diene metathesis polymerization (ADMET) has been shown to be an efficient tool for the synthesis of a wide variety of polymers and polymer architectures that are not available using other polymerization methods.[3] Among them, polyesters can be prepared with molecular weights that range between 20.000 and 70.000. In the present work, a renewable phosphorus containing monomer bearing two 10-undecenoic acid moieties has been homopolymerized and copolymerized with a 10-undecenoic acid derived monomer[4] via ADMET using the Grubbs second generation metathesis catalyst. Polymers with Mn up to 65.000 were obtained in absence of solvent. This procedure allowed us to synthesize a variety of polyesters with controlled phosphorus contents which are promising candidates for flame retardant materials.

1. Yang, S. C.; Kim, J. P. J App Polym Sci, 2007, 106, 2870–2874
2. Meier, M. A. R.; Metzger, J. O.; Schubert, U. S. Chem Soc Rev, 2007, 36, 1788–1802
3. Schwendeman, J. E.; Church, A. C.; Wagener, K. B. Adv Synth Catal, 2002, 344, 597-613
4. Rybak, A; Meier, M. A. R. ChemSusChem 2008, 1, 542-547