Preparation of gallic acid-polydimethylsiloxane codeposited carbon fibers to improve interfacial properties of epoxy composites

A novel method, drawing inspiration from the chemistry principle observed in mussels, has been recently developed to augment the wettability and adherence of carbon fibers (CFs) within epoxy resin matrix. This technique entails the concurrent application of gallic acid and aminopropyl double terminated polydimethylsiloxane on CF surfaces via a direct method. Advanced analytical techniques like scanning electron microscopy, X-ray diffraction, infrared and Raman spectroscopy, along with X-ray photoelectron spectroscopy, confirmed the effective simultaneous deposition of these agents, possibly via Michael addition or Schiff base reactions. Incorporation of these treated fibers into epoxy composites resulted in notable performance enhancements. The composites with gallic acid and polydimethylsiloxane modified fibers exhibited up to 14%, 13%, and 27% improvements in interlaminar shear strength, flexural modulus, and flexural strength, respectively, compared to their counterpart with untreated fibers. These results indicate that combining gallic acid and polydimethylsiloxane on CFs is a potent approach to boost the interface qualities of CF-reinforced epoxy resin composites.