Improved Interfacial Interaction of Carbon Fiber-Reinforced Polyamide 6 Composites by Sizing Agent of Blocked Isocyanate

Abstract

To enhance the interfacial properties of carbon fiber (CF)-reinforced polyamide 6 (CF/PA6) composites, a novel blocked isocyanate (BI) / polyurethane (PU) sizing agent was prepared by dispersing BI in an aqueous PU emulsion. It was then applied to the CF surfaces for modification via a room-temperature sizing method. The results indicated that the BI/PU sizing layer significantly enhanced CF surface wettability, facilitating impregnation of PA6 resin onto fibers. With the increase in BI content, the interfacial shear strength (IFSS) of CF/PA6 composites was enhanced. The IFSS of the desized CF/PA6 composites was 46.8 MPa. When the sizing agent with a BI mass fraction of 3.0% was applied, the IFSS of the CF/PA6 composite reached 62.3 MPa, which represented an increase of 33.1% compared with that of the desized CF/PA6 composite. The proposed method offers an efficient and scalable surface modification strategy for high-performance thermoplastic composites.

Keywords

carbon fiber / sizing agent / blocked isocyanate / polyamide 6 / interfacial shear strength

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