Kinetics of Binder Burnout

Fundamental studies in the literature of the kinetics of binder burnout are scarce. This material has been developed by synthesis of several articles [3,10,46,47] and the application of principles of gas—solid reac- 

FIGURE 15B Typical rate versus concentration curve for autocatalytic reactions of the iype -rA = k Cf), A is the polymer. 

Binder burnout can be kinetically limited over several steps  

Mass transfer of ojg en in the boundary layer surrounding the green body, 

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Accounting for these rate determining steps the kinetics of binder burnout can be established for simple decompositions of polymers, such as depolymerization and the oxidation of carbon. For polymers with... 

P is the number of polymer molecules of degree of polymerization n, R is the number of radicals found in a volume V, R is the number of polymer radicals with degree of polymerization n found in a volume, V. For other definitions, please use the nomenclature associated with Table 15.2. Noting equation 15.14, the kinetics of polymer degradation are very complex. Only the most simple mechanisms have been thoroughly researched. These simplified reactions presented in Table 15.2 are sometimes zero order, more frequently first order, and infiiequently second order in polymer mass. These simplified rate expressions are typically used to model binder burnout. 

The effects of oxides on the binder burnout of poly(vinyl butyral) (PVB) was studied by Masia et al. [26]. The binder decomposition kinetics in air was shown to be a strong function of the ceramic oxide present. In all cases, the oxide decreased the temperature necessary for thermal decomposition compared to PVB alone. The order was the following ... 

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