Suppressing droplet coalescence and aggregation in immiscible homopolymer blends by interfacially cross-linked compatibilizers

In this work, we study the effect of reactive compatibilization on morphological and rheological properties of immiscible homopolymer blends of polydimethylsiloxane (PDMS) and polyisoprene (PI). The blend systems contained a chemical reaction between amine-functionalized PDMS and maleic anhydride-functionalized PI additives at high temperatures. Interfacially cross-linked compatibilizers obtained with this procedure are investigated through dynamic rheological measurements and Fourier transform infrared spectroscopy. The results show that the interfacial cross-linking constituting strong heterogeneous network is symmetric, as it reduces the sizes of the dispersed phase with higher stability in both compatibilized PI-continuous and PDMS-continuous blends compared to their uncompatibilized counterparts. A complete suppression of droplet coalescence can be concluded due to the superposition of linear viscoelasticity of the reactively compatibilized blends after different shearing protocols. In the previous work [C. DeLeo et al., J. Rheol. 55(4), 713–731 (2011)], however, the weak network at room temperature was found to have an asymmetric effect on the suppression of drop coalescence.