Regulating Self‐Welded Carbon Fiber Networks in Silicone Rubber Composites: Mixing Procedure and Fiber Dispersion

ABSTRACT The construction of a self‐welded fiber scaffold within a polymer matrix represents a key focus in composite research, wherein a solder joins randomly dispersed fibers. A central challenge is selectively localizing the solder at fiber junctions while avoiding capillary‐induced bundling. This study fabricated a silicone rubber (SR) composite with well‐dispersed carbon fibers (CF) and a self‐welded scaffold by using epoxy resin (EP) as the solder, optimizing kinetic parameters including mixing procedure, annealing time, and viscosity. With procedure 1 (adding EP to SR/CF mixtures), we found that annealing of the uncured specimens increased the encapsulation ratio of EP ( N _EP ) on fiber surface, but the network‐essential encapsulation efficiency ( e ) increased first then decreased, manifested as the composite's storage modulus and electrical conductivity both peaked then declined. Longer mixing time requires shorter annealing time for peak values. We confirmed that capillarity‐induced fiber bundling reduces e , causing agglomeration and network disruption. Higher solder viscosity delays bundling. Procedure 2 (adding CF to SR/EP mixtures) suppressed fiber bundling during annealing but presented lower N _EP and e , forming weaker and slower scaffolds in compression tests compared to Procedure 1. This work elucidates kinetic mechanisms of fiber scaffold formation and guides composite processing.