Thermal behaviour and degradation of a liquid crystalline alkylene-aromatic polyester: Poly(decamethylene-fumaroyl-bis-4-oxybenzoate) Fabio Bertini a, * , Vjacheslav V. Zuev b a Istituto per lo Studio delle Macromolecole e C.N.R., Via Bassini 15, Milano 20133, Italy b Institute of Macromolecular Compounds of the Russian Academy of Sciences, Bolshoi pr.31, Sankt Petersburg 199004, Russian Federation Received 10 April 2007; accepted 24 June 2007 Available online 17 July 2007 Abstract The thermal behaviour and degradation of an alkylene-aromatic liquid crystalline polyester, poly(decamethylene-fumaroyl-bis-4-oxyben- zoate), were studied by thermogravimetric analysis under dynamic conditions and by pyrolysisegas chromatography and pyrolysisegas chromatography/mass spectrometry in the temperature range 450e650  C. Among the degradation products detected, maleic anhydride, phenol, 4-hydroxybenzoic acid and the corresponding decenyl ester were the most abundant. The type and the composition of the pyrolysis products gave useful information about the mechanism of thermal degradation. The polyester decomposition starts with a free-radical scission in the mesogenic fragment and continues with electrocyclic reactions in the spacer. The influence of fullerene C 60 addition and of the deuteration of the decamethylene spacer on thermal behaviour and degradation were investigated. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Poly(decamethylene-fumaroyl-bis-4-oxybenzoate); Liquid crystalline polyesters; Pyrolysisegas chromatography; Thermal behaviour; Degradation mechanism; Fullerene C 60 1. Introduction Main chain alkylene-aromatic liquid crystalline (LC) polyes- ters have been widely studied over the past decades because of their unique properties that include their ability to be oriented in the desired liquid crystal phase and then quenched to create a highly ordered, strong solid [1]. As these technologies continue to develop, an increasing variety of new materials with strong and light-weight properties will become available. To achieve the de- sired physical properties, LC polymers with various chemical structures and molecular architectures including both the meso- genic groups and flexible spacers have been designed [1]. Thermal decomposition of LC polyesters is relevant to the deterioration of material properties during high-temperature processing. These materials have to meet stringent require- ments, and this stimulates both improvement of synthetic pro- cedures and material properties’ analyses including thermal behaviour and degradation mechanism. For this purpose we synthesized LC polyester, poly(deca- methylene-fumaroyl-bis-4-oxybenzoate) (I), and its thermal behaviour and degradation mechanism have been investigated by thermogravimetric analysis in dynamic conditions and by pyrolysisegas chromatography techniques in isothermal conditions. * Corresponding author. Tel.: þ39 02 23699356; fax: þ39 02 70636400. E-mail address: bertini@ismac.cnr.it (F. Bertini). 0141-3910/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.polymdegradstab.2007.06.009 Polymer Degradation and Stability 92 (2007) 1669e1676 www.elsevier.com/locate/polydegstab