Spontaneous frontal polymerization

Spontaneous Frontal Polymerization Propagating Front Spontaneously Generated by Locally Autoaccelerated Free-Radical Polymerization... 

Asakura, K., Nihei, E., Harasawa, H., Ikumo, A., and Osanai, S. (2004) Spontaneous frontal polymerization propagating front spontaneously generated by locally autoaccelerated fee-radical polymerization. Nonlinear Dyn. Polym. Syst., 869, 135-146. 

DBTDL was used as a catalyst in the frontal polymerization of 1,6-hexanediisocyanate with ethylene glycol. In frontal polymerization the polymerization is locally initiated and the exotherm of the reaction propagates the polymerization throughout the system. Pyrocatechol was used to avoid spontaneous polymerization. Pyrocatechol chelates tin and depresses the catalytic activity at room temperature without affecting catalysis at the higher temperature. To achieve a uniform advancing reactive front, and to avoid fingering, the viscosity of the blend was increased with colloidal silica. 

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