ORIGINAL Crosslinking of a polyester resin in the heated plain sheet copper mould Vanja Kosar Æ Zoran Gomzi Received: 14 September 2007 / Accepted: 2 April 2008 / Published online: 15 April 2008 Ó Springer-Verlag 2008 Abstract The crosslinking of the unsaturated polyester was studied by using experiments and a model of the process. The kinetic parameters were calculated from the heat flux–time curves obtained by differential scanning calorimetry (DSC, Netzsch–Simultaneous Thermal Ana- lyser DSC 200), working in DSC (dynamic) mode. The temperature–time histories were studied in plain sheet copper mould. The mathematical model was constructed by taking into account the heat transferred by conduction through the resin, as well as the kinetics of heat generated by the crosslinking reaction. The contributions to the rise in temperature from heat conduction and chemical reaction are different in different parts of the composite, and can explain the temperature-, or degree of crosslinking (DOC)– time histories. By considering temperature–time histories developed within the sample, more extensive knowledge of the process can be obtained. The effect of the heat transfer by conduction through the composite as well as the internal heat generated by the cure reaction is clearly shown, despite the complexity of the process. Finally, good agreement between experimental data and predicted mathematical model of the crosslinking process in plane sheet mould was shown. List of symbols A r arrhenius number, s -1 c index (composite) c p specific heat capacity, J kg -1 K -1 E a activation energy, kJ mol -1 dH/dt heat flow, J s -1 g -1 DH r heat of reaction, kJ kg -1 k rate constant, s -1 L mould width, 0.01 m m, n exponents in Eqs. (6) N number of experimental data P degree of crosslinking r radial position, m R g gas constant, 8.314 J mol -1 K -1 r A rate of reaction, s -1 t time, s T temperature, K T 0 initial temperature, 298 K T m mould wall temperature, K T gly glycerol temperature, K y iexp. experimental data i y iteor. evaluated data i w mass fraction z position in mould, m Greek symbols h m Dimensionless mould wall temperature q Density, kg m -3 k Heat conductivity, J m -1 s -1 K -1 a Thermal diffusivity, m 2 s -1 1 Introduction One of the main topics in the moulding processing is a design of the mould geometry [1]. All moulds are a com- bination of the three main geometries: cylinder, sphere, or plain sheet. In our previous works crosslinking in the V. Kosar (&)  Z. Gomzi Faculty of Chemical Engineering and Technology, Department of Reaction Engineering and Catalysis, University of Zagreb, Savska c. 16, 10000 Zagreb, Croatia e-mail: vkosar@fkit.hr 123 Heat Mass Transfer (2008) 44:1511–1518 DOI 10.1007/s00231-008-0399-z