Release of interfacial thermal stress and accompanying improvement of interfacial adhesion in carbon fiber reinforced epoxy resin composites: Induced by diblock copolymers

In this work, diblock copolymer Hydroxyl-Terminated poly (n-butylacrylate)-b-poly (glycidyl methacrylate) (OH-PnBA-b-PGMA) was synthesized by atom transfer radical polymerization (ATRP) and was then introduced into the interface between carbon fiber and epoxy resin. Micro-Raman spectroscopy and microbond test were employed to study the influence of grafted polymers on the interfacial properties. From the Micro-Raman spectroscopy results, the interfacial thermal stress in carbon fiber/epoxy resin micro-composite decreases from 546.9 MPa to 451.9 MPa due to the grafting of OH-PnBA180-b-PGMA70 on the carbon fiber. Meanwhile, the interfacial shear strength (IFSS) value increases rapidly from 29.8 MPa to 52.3 MPa, measured by microbond test. Therefore, it can be concluded that such a diblock copolymer can effectively both release the thermal stress and improve the interfacial adhesion. Moreover, it proves that the length of PnBA block has great influence on the interfacial properties of carbon fiber/epoxy composite.