Phase Morphology of NR/SBR Blends: Effect of Curing Temperature and Curing Time

• Main Authors: Darja Klat, Hossein Ali Karimi-Varzaneh, Jorge Lacayo-Pineda
• Format: Article
• Language: English
• Published: MDPI AG 2018-05-01
• Series: Polymers
• Subjects: rubber; blend morphology; phase separation; miscibility; atomic force microscopy; transmission electron microscopy; surface free energy
• Online Access: http://www.mdpi.com/2073-4360/10/5/510

The morphology of natural rubber/styrene–butadiene rubber blends (NR/SBR) was characterized by atomic force microscopy (AFM), with regard to curing temperature and curing time. The changes in blend morphology were directly visualized by AFM which confirmed the results of indirect experiments like differential scanning calorimetry (DSC). Comparing the phase morphologies at different curing temperatures indicated that the domain size of SBR increases with temperature at lower curing temperatures, but domain growing stops at the latest scorch time. This effect is explained by longer scorch times at low curing temperatures which facilitate phase separation, while the short scorch times at higher temperatures meant that the coalescence of SBR phases was hindered by cross-linking between polymer chains.