Renewed interest in the reinforced carbon graphite composites has intrigued the community in the advanced materials fields. In this work, we present a simple carbon nanofibers reinforced carbon graphite composites synthetic method by incorporating mixture of coal tar pitch, synthetic graphite, pitch coke and the dispersion liquid of carbon nanofibers via liquid-phase mixing process. The impact of carbon nanofiber utilization on the microstructures and mechanical properties of carbon graphite composites are studied systematically. The covalent surface modification of carbon nanofibers effectively improves its microstructure and thereby promotes the carbon graphite composites’ dispersion behavior. We propose that a small amount of carbon nanofibers could promote the carbonization process of carbon graphite composites, facilitating the densification of carbon graphite composites and reducing the undesired open porosity. The amount of 0.7 wt % of carbon nanofiber concentration allows the enhancement of bend and compressive strength of carbon graphite composites up to 36.50 MPa and 60.46 MPa, increased by 167.9% and 146.9% compared with the pure carbon graphite composite, respectively. Our findings can be rationalized due to the improvement in the mechanical strength of carbon graphite composites could be attributed due to pull-out of carbon nanofibers from the matrix and bridging effect across the crack pores within the matrix.

    Abstract
    1 Introduction
    2 Experimental section
        2.1 Materials
        2.2 Surface oxidation and functionalization of CNFs
        2.3 Preparation of DAM-CNFs reinforced CGCs
        2.4 Mechanical properties and microstructure characterizations
    3 Results and discussion
        3.1 Surface structure of CNFs and DAM-CNFs
        3.2 Dispersion of CNFs in THF
        3.3 Effect of DAM-CNFs content on the microstructure of the CGCs
        3.4 Effects of DAM-CNFs content on the physical and mechanical properties of the CGCs
    4 Conclusions
    Acknowledgements 
    References

• Yixing Chen(College of Materials Science and Engineering, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University)
• Chuanjun Tu(College of Materials Science and Engineering, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University)
• Yanli Liu(College of Materials Science and Engineering, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University)
• Ping Liu(College of Materials Science and Engineering, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University)
• Pei Gong(College of Materials Science and Engineering, Hunan Province Key Laboratory for Advanced Carbon Materials and Applied Technology, Hunan University)
• Guangning Wu(College of Electrical Engineering, Southwest Jiaotong University)
• Xia Huang(College of Materials Science and Engineering, Sichuan University of Science & Engineering)
• Jian Chen(College of Materials Science and Engineering, Sichuan University of Science & Engineering)
• Tianhua Liu(Jinan Wanrui Carbon Co., Ltd.)
• Jizhou Jiang(School of Environmental Ecology and Biological Engineering, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education,)