Microstructural analysis of natural rubber/millable polyurethane blends using positron annihilation lifetime spectroscopy

Positron annihilation lifetime spectroscopy (PALS) was used to investigate the relationship between the free volume properties and miscibility of natural rubber (NR)/millable polyurethane (MPU) blends. The free volume parameters (Vf and I3) have been found to be increased regularly with an increase in NR concentration in the blend. The morphological analysis of the samples has been performed by scanning electron microscopy. The results obtained from PALS technique have been correlated with the observations from X-ray diffraction analysis and differential scanning calorimetry. Thermogravimetric examination highlighted the enhancement in thermal stability upon blending MPU with NR