Silicone rubber reinforced by self-welded short glass fibers: Effect of resin viscosity on preferential segregation

Abstract Self-organization of mesoscopic materials (≥10 μm) using capillary forces is an attractive strategy to assemble small objects into ordered structures. In this report, a small amount of epoxy resin (EP) is added as a “solder” in glass fibers (GFs)-reinforced silicone rubber (SR). The randomly dispersed GFs are found spontaneously self-welded into a three-dimensional GF-EP network under the driving force of capillarity. We center on investigating the effects of viscosity ratio of EP to SR (λ) and the matrix viscosity (ηm) on the size of EP domain, the encapsulation ratio (NEP) of EP on GF and the morphology evolution of self-welded GF scaffolds. NEP increases with decreasing ηm of the SR matrix. At a given matrix, enlarging the viscosity difference of EP from SR seems to maximize NEP. More interestingly, decreasing ηm can not only increase NEP, but also promote preferential segregation at the junction points of GFs. We confirm that NEP increases because of the viscosity-related enlargement of the EP domain size. The self-welded rigid GF-EP scaffolds mechanically support the SR matrix, thus providing a new strategy for the design of high-strength and pressure-resistant functional rubber composite materials.