It is commonly assumed that a higher oxygenated content on the surface of carbon fibers will lead to high interfacial adhesion. Thus, carbon fibers are exposed to oxidizing treatments to increase surface polarity. Here, we examine the interfacial interactions of a range of thermoset and thermoplastic polymers with carbon fibers that have a grafted polyethylene oxide (PEO) chains to their surface. This provides an extremely hydrophilic surface, without potential degradation of the fiber via chemical oxidation. We find that high surface polarity does not always correlate to high interfacial adhesion; in some instances, unsized hydrophobic carbon fibers possess equal or better fiber-to-matrix adhesion than treated hydrophilic carbon fibers. The most notable example is in vinyl ester resin, in which the presence of an alkyne group, able to participate in the radical polymerization process, provides significant improvements in interfacial shear strength (IFSS) compared to a larger, and polar, PEO chain.

通常认为，碳纤维表面的含氧量较高会导致较高的界面粘合性。因此，碳纤维受到氧化处理以增加表面极性。在这里，我们检查了一系列热固性和热塑性聚合物与碳纤维的界面相互作用，碳纤维的表面接枝了聚环氧乙烷（PEO）链。这提供了非常亲水的表面，而不会由于化学氧化作用而使纤维潜在降解。我们发现，高的表面极性并不总是与高的界面粘合性相关。在某些情况下，未处理的疏水性碳纤维与经处理的亲水性碳纤维相比，具有相同或更好的纤维对基质粘合性。最著名的例子是乙烯基酯树脂，其中存在炔基，