Pyrolysis fuel oil (PFO) is used for the manufacturing of high-purity pitch for carbon precursor due to its high carbon content, high aromaticity, and low heterogeneous element and impurity content. Pitch is commonly classified with its softening point, which is most considerable physical property affecting to various characteristics of the carbon materials based on pitch, such as electrical and thermal conductivity, mechanical strength, and pore property. Hence, the softening point should be controlled to apply pitch to produce various carbon materials for different applications. Previous studies introduce reforming process under high pressure and two step heat treatment for the synthesis of pitch with high softening point from PFO. These methods lead to a high process cost; therefore, it is necessary to develop a process to synthesize the pitch with high softening point by using energy effective process at a low temperature. In this study, waste polyethylene terephthalate (PET) was added to control the softening point of PFO-based pitch. The pitch synthesized by the heat treatment with the addition of PET showed the softening point higher than that of the pitch synthesized with only PFO. The softening point of PFObased pitch synthesized at 420 °C was 138.3 °C, while that of the pitch synthesized by adding PET under the same process conditions was 342.8 °C. It is proposed that the effect of the PET addition on the increase in the softening point was due to the radicals generated from thermal degradation of PET. The radicals from PET react with the PFO molecules to promote the polymerization and finally increase the molecular weight and softening point of the pitch. In addition, activated carbon was prepared by using the pitch synthesized by adding PET, and the results showed that the specific surface area of the activated carbon increased by the addition of PET. It is expected that the pitch synthesis method with PET addition significantly contributes to the manufacture of pitch and activated carbon.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Pitch synthesis using PFO and PET
        2.3 Pitch activation using KOH
        2.4 Analysis of characteristics
    3 Results
        3.1 Change of softening point depending on PET addition
        3.2 Pore characteristics of activated carbon products prepared by using pitch synthesized under different conditions
    4 Discussion
        4.1 Pitch pyrolysis characteristics depending on pet addition
        4.2 Change in molecular weight of pitch depending on PET addition
    5 Conclusion
    Acknowledgements 
    References

• Cheol Hwan Kwak(C1 Gas and Carbon Convergent Research, Korea Research Institute of Chemical Technology (KRICT), Department of Biological Engineering, Inha University)
• Sang Wan Seo(C1 Gas and Carbon Convergent Research, Korea Research Institute of Chemical Technology (KRICT), Department of Applied Chemical Engineering, Chungnam National University)
• Min Il Kim(C1 Gas and Carbon Convergent Research, Korea Research Institute of Chemical Technology (KRICT))
• Yun Suk Huh(Department of Biological Engineering, Inha University)
• Ji Sun Im(C1 Gas and Carbon Convergent Research, Korea Research Institute of Chemical Technology (KRICT), Advanced Materials and Chemical Engineering, University of Science and Technology (UST))