Post-Cure Prediction Responses

It was also apparent that a way of predicting whether a TPU s properties can be improved by a higher temperature post-curing step is available if during the DMTA test the E value is observed to increase with temperature, then the properties of the TPU can be improved, if required, by post-curing, for example see Fig. 9.7 of compound 10 post-cured. 

The following conclusions can be deduced from this work  

Polyurethane elastomers from both polyester and polyether polyols have been made from the diisocyanates CHDI and PPDI and found to possess high strength and low compression set. A feature of all 

With CHDI-based PUs, it is essential to use a catalyst to complete the polymer formation and obtain full strength. Stannous octoate is satisfactory for this purpose. Also enhancement of properties can be obtained by post-curing in hot air at temperatures greater than those used for the initial PU cure 24 h at 140°C has been found to be a satisfactory set of post-curing conditions. 

PPDI-based PUs do not need a catalyst to achieve complete polymerization and post-curing does not result in improvement in physical properties. 

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