Rubber Microfibers with Morphological Stability Prepared Through Combination of Electrospinning and In-Situ Chemical Crosslinking

Rubber microfibers with morphological stability were prepared through combination of electrospinning and in-situ chemical crosslinking.  The rubbers, including polybutadiene rubber (BR), butyl rubber (IIR), and silicon rubber (SiR) were first kneaded on a two-roll mill and dissolved in tetrahydrofuran (THF) to form stable solutions.  Prior to electrospinning, camphorquinone (CQ) for BR and IIR, while two-part platinum catalyst for addition curing of SiR, were added into the solutions for in-situ chemical crosslinking.  The morphology and crosslinking density of electrospun rubber microfibers were investigated.  The results indicated that, for the formation of uniform microfibers without beads and/or beaded fibers, the concentration of spinning solution had to be higher than the “critical chain entanglement concentration (Ce)” and the value of Ce divided by the value of C* appeared to be a constant of ~1.8. The study suggested that the in-situ chemical crosslinking was an effective method to substantially improve the morphological stability of electrospun fibers; upon prolonged storage under ambient condition or even upon immersion in THF (a good solvent for BR, IIR and SiR), the crosslinked BR, IIR and SiR fibers well-retained their morphology. 

Key words: Electrospinning; Fiber formation; Rubber; In-situ chemical crosslinking