JOURNAL OF POLYMER ENGINEERING

 Vol. 23, No. 3, 2003, page 149

FLAME-RETARDED HALOGENATED UNSATURATED POLYESTER RESINS: THERMAL DECOMPOSITION STUDY

Ewa Kicko-Walczak

 Industrial Chemistry Research Institute

Warsaw, Poland

 ABSTRACT

      The thermal decomposition of halogenated unsaturated polyester resins (UPRs), flame retarded by zinc hydroxystannate and cross-linked with styrene, has been investigated by thermogravimetry (TG) in both dynamic and isothermal mode, and TG coupled on-line with Fourier transform infra red spectroscopy (TG-FTIR) or mass spectroscopy (TG-MS). The data from TG analysis show that degradation proceeds in two steps for pure as well as modified UPR, while the char residue at 500⁰C was considerably higher for flame-retarded resins. Analysis of the volatile decomposition products by FT-IR and MS spectrocopy revealed that, during controlled heating, emission of phthalic anhydride takes place at ca. 330⁰C, then at ca. 380⁰C styrene and a complex mixture of other aromatic compounds is evolved. Further studies by TG-FTIR revealed that evolution of CO₂ is considerably lowered by zinc hydroxystannate, whereas at a higher stage of decomposition evolution of H₂O and HBr (traces) can be identified. On the basis of the results obtained a mechanism of decomposition was proposed that takes into account tin compounds reactions with the products coming from ester linkage rupture processes. 

Keywords:     unsaturated polyester resins, thermal degradation, zinc hydroxystannate, hyphenated thermal analysis methods

P.O. Box 35010, Tel Aviv, Israel, 61350. Tel: 972-3- 562-8540; Fax: 972-3-562-8538

E-mail: h_freund@netvision.net.il; website: https://www.freundpublishing.com