Thermal investigations of deformation induced morphological developments

2 Thermal investigations of deformation induced morphological developments 

If you saw a heat wave, would you wave back (Stephen Wright) 

Not applicable for PUs, but what about us I would gladly wave back when it is cold outside. Numerous studies had been made on the influence of temperature on the PUs deformation. A series of model MDI based PUs were characterized by Crawford et al [220] before, and after varying degrees of strain aging to study the effect of strain on the polymer morphology and mechanical properties. The segmented materials were synthesized by using the one-shot technique. The molar ratios of the model polymers were varied. 

Heat aging the of the materials without strain elongation was shown to enhance domain ordering and phase separation and resulted in improved abrasion resistance. 

The mechanical hysteresis of a PU investigated by Gorce based on MDl/BDO and PTMO of molar 2 000 g/mol was also found to be sensitive to the temperature-dependent morphologies of this material and to the morphological changes induced by the strain level and deformation energy during a deformation cycle [291]. 

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