High mechanical properties of covalently functionalized carbon fiber and polypropylene composites by enhanced interfacial adhesion derived from rationally designed polymer compatibilizers

The carbon fiber reinforced plastics (CFRP) are still limited the used in the automotive industry mainly by the weak interfacial adhesion between the fiber and polymer matrix. Herein, to improve interfacial interactions between the carbon fiber (CF) and polypropylene (PP) matrix, poly(dimethylaminoethyl methacrylate)-b-poly (methyl methacrylate) (PDMAEMA-b-PMMA, PDM) compatibilizers are applied to functionalize the CF surface through a covalent bonding with epoxide groups on the chemically modified CF surface with tertiary amines in the PDMAEMA block, which induced intermolecular entanglement with PP chains with the PMD compatibilizers. The acquired compatibilizer-functionalized CF (CECF) was applied to fabricate PP composites by a melt-mixing method. The highly improved interfacial adhesion between the CECF and PP was confirmed by evaluating thermal, morphological, rheological, and mechanical properties. Based on the significantly enhanced interfacial adhesion, notably, the tensile strength and modulus of the CECF/PP composite exhibited a massive increase by ca. 312% and 664%, respectively, relative to those of the PP resin. The Ashby plot facilitated understanding that the acquired mechanical properties of the CECF/PP composite showed a relatively ideal position compared to reported PP composites and centered on the commercially available region in automotive components.

Automated summary

By using compatibilizer-functionalized carbon fiber, the interfacial adhesion of carbon fiber-reinforced polypropylene composites was significantly improved, leading to enhanced mechanical properties, specifically a substantial increase in tensile strength and modulus. This resulted in the composite exhibiting ideal mechanical properties in comparison to reported polypropylene composites, particularly in the commercially available region for automotive components.