The melting polymerization of acetaldehyde

Abstract

The melting polymerization of acetaldehyde is studied. The melting polymerization does not change by the pretreatment of various immersion time in liquid nitrogen and the surface effect with various surface area which is in contact with acetaldehyde, but is affected by the ΔT which is the temperature difference between the melting point of acetaldehyde and the reaction temperature. The yield and the intrinsic viscosity of the polymer increase as being smaller the ΔT. On the other hand, the intrinsic viscosity diminishes with reaction time. From the initial rate of the melting polymerization, the value of -4.46kcal/mole is obtained as the apparent activation energy and this value is in good agreement with the values obtained from the high pressure polymerization of acetaldehyde at low temperature with no catalyst. The presence of the substances mixed homogeneously with acetaldehyde retards the melting polymerization remarkably in the same way as the high pressure polymerization. The effect of small amount of water or acetic acid on the melting polymerization is analogous to the high pressure polymerization rather than the freezing polymerization. Namely, the polymer yield of the melting polymerization is little affected by water, but the presence of acetic acid retards the melting polymerization remarkably.