Coupling of carbon fibers to polycarbonate: Surface chemistry and adhesion

Lívia Dányádi, János Gulyás, Béla Pukánszky

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11 Citations (Scopus)


Anodically oxidized carbon fibers (CF) were treated with four different coupling agents containing epoxy, anhydride, and isocyanate functionality. The bonding of the coupling agents to the fiber surface was determined by dissolution experiments, while the chemical composition of the surface was studied by diffuse reflectance infrared spectroscopy (DRIFT), Micro-composites were prepared from polycarbonate resins (PC) by compression molding. The effect of surface coverage, processing temperature and molecular weight on interfacial adhesion (IFSS) was determined by fragmentation. The amount of coupling agent bonded to oxidized carbon fiber depends on its chemical structure and on the reactions taking place on the fiber surface. Several of the coupling agents formed a polymer layer on the surface; its structure also influenced both coupling to the matrix and the strength of interaction. The organofunctional group of the coupling agents reacts with the chain-end hydroxyl groups of PC. The number of these is limited, significantly lower than the concentration of reactive groups available on the surface of the coated fiber. As a consequence, interfacial interaction can be improved only to a limited extent in PC/CF composites; similar improvement can be achieved in IFSS with the three coupling agents reacting with the polymer. The agent containing anhydride functionality does not enter into coupling reactions with PC. Interfacial adhesion increased with processing temperature, which could be explained by the increased rate of reaction. The effect of molecular weight on interfacial adhesion is not clear; the results published earlier could not be confirmed unambiguously.

Original languageEnglish
Pages (from-to)61-76
Number of pages16
JournalComposite Interfaces
Issue number1
Publication statusPublished - Apr 21 2003



  • Carbon fiber
  • Chemical coupling
  • Fragmentation
  • Infrared spectroscopy
  • Polycarbonate composites

ASJC Scopus subject areas

  • Ceramics and Composites
  • Physics and Astronomy(all)
  • Surfaces, Coatings and Films

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