Mechanical properties of carbon fiber/polypropylene composites using carboxylic-acid-modified polypropylene without and with oxazoline-containing polymer coated on carbon fiber

There have been many reports on the use of maleic-anhydride-modified polypropylene (MAn-g-PP) as a compatibilizer for carbon fiber (CF)/polypropylene (PP) composites, but there are very few examples using carboxylic-acid-modified PP. The purpose of this paper is to investigate the effect of hydrogen bonding at the CF/ PP interface contributed by the addition of carboxylic-acid-modified PP on the mechanical properties of composites, and to propose a new interface design for improving the mechanical properties of composites by combining a poly-2-vinyl-2-oxazoline (Pvozo) coating on the CF surface with the addition of carboxylic-acidmodified PP to composites. For this purpose, poly methacrylic acid-grafted polypropylene (PMAA-g-PP) was synthesized independently and added to the CF/PP composite. The addition of PMAA-g-PP enhanced the tensile properties of the composites due to the effect of hydrogen bonding at the CF/PP interface. The combination of PMAA-g-PP addition to the composites and the use of Pvozo-coated CF resulted in better interfacial adhesion and further improved the tensile properties of the composites. Increased entanglement with matrix PP molecules due to carboxylic-acid-modified PP being grafted onto the CF surface and different bonding modes at the CF/PP interface were suggested to contribute to the mechanical properties of the composite.

Automated summary

This paper investigates the effect of carboxylic-acid-modified polypropylene (PP) on the mechanical properties of carbon fiber (CF)/polypropylene (PP) composites, and proposes a new interface design to improve the mechanical properties. The addition of carboxylic-acid-modified PP and poly-2-vinyl-2-oxazoline (Pvozo) coating on CF resulted in better interfacial adhesion and improved tensile properties. Increased entanglement with matrix PP molecules and different bonding modes at the CF/PP interface were suggested to contribute to the mechanical properties of the composite.