Design and construction for the interface between carbon fiber and epoxy via vinyl alkoxysilane modification

The construction of the interface for carbon fiber reinforced composites is important to the exhibition of excellent mechanical properties. Chemical bonding connection through the transition layer of sizing agent is the con-ventional method. However, physical connection is also benefit to the interfacial properties. Vinyl alkoxysilane (vinyl POSS) was designed as a bridge to introduce physical locking and chemical bonding simultaneously. A three-dimensional cage structure was formed on the surface of carbon fiber, that enables the matrix to enter inside and eventually form physical cross-linking. The effect of vinyl POSS on the stability of the sizing agent emulsions, surficial chemical structure and free energy was also evaluated as positive ones. The interfacial shear strength was improved significantly since a new complex connection interface was constructed. When the content of vinyl POSS was 1.2%, the interfacial shear strength was 97.0 MPa, which was increased by 92.5% compared with that without modification.

Automated summary

The construction of the interface for carbon fiber reinforced composites plays a crucial role in exhibiting excellent mechanical properties. The combination of chemical and physical bonding through the use of sizing agent and vinyl POSS enhances the interfacial properties, resulting in a significantly improved interfacial shear strength.