Chemical Engineering Communications, Vol.130, 45-52, 1994
Steam Oxidation of Carbon Formed by Thermal-Degradation of PMMA in Alumina
In the processing of multilayer ceramic multichip modules (MCM’s), a ceramic substrate, such as alumina, along with a polymer, such as poly(methyl methacrylate) (PMMA), solvents, plasticizers, flocculants is thermally degraded before sintering. The thermal degradation of PMMA from the green body of oxide ceramics leaves behind some amount of residual carbon in the ceramic. Carbon concentration above 100 ppm has a deleterious effect on the physical properties such as flexural strength, density, breakdown voltage and densification behavior of the ceramic. This paper discusses the kinetics of oxidation of carbon formed by the thermal degradation of poly(methyl methacrylate) in alumina. Pellets of 5 Irm and 1 pm size alumina were made at 6000 psig in a single step change. Kinetic runs were made in the temperature range of 673 to 993 K with steam as the oxidant at a flow rate of 9.96E-03 g/cm(2) sec The organics (polymethyl methacrylate, methyl ethyl ketone, methanol) concentration was varied from 5 to 20 by weight%. The oxidation products were analyzed using a Varian 3700 gas chromatograph coupled with CDS 111 integrator, and by volumetric analysis. Carbon analysis was carried out at the IBM Fishkill center using a Leco analyzer. Kinetic rates and activation energies are evaluated.
Keywords:POLY(VINYL BUTYRAL)