Preparation of Isotropic Carbon Fibers from Kerosene-Purified Coal Tar Pitch by Co-Carbonization with Pyrolysis Fuel Oil.

Seon Ho Lee,Song Mi Lee,Doo-Hwan Jung,Haksoo Han,Seong-Ho Yoon,Seungjoo Park

doi:10.3390/ma14216280

Abstract

An inexpensive and general-purpose carbon fiber was prepared using coal tar pitch. In contrast to the solvent extraction process employing expensive solvents, a low-cost centrifugal separation method facilitated the reduction of loss due to the pitch purification and an overall yield increase. The coal tar pitch purified by centrifugation and subsequently co-carbonized with pyrolysis fuel oil improved in spinnability. Moreover, the resulting spinnable pitch had a softening point of 250 °C. The obtained carbon fibers were heat-treated at 1000 °C for 5 min, resulting in a tensile strength of approximately 1000 MPa and an average diameter of 9 μm. In this study, we present an effective method for obtaining low-cost general-purpose isotropic carbon fibers.

Highlights

Fuel economy is in high demand owing to the depletion of petroleum resources and environmental problems caused by large amounts of fine dust emissions
Coal tar pitch was first centrifuged with the low-cost Kerosene method, co-carbonized with pyrolysis fuel oil (PFO)
Kerosene was heated at 150 ◦C; afterwards, the solid content was separated and extracted, and filtrated and purified

Summary

Introduction

Fuel economy is in high demand owing to the depletion of petroleum resources and environmental problems caused by large amounts of fine dust emissions. Lightening the weight of the vehicle body structure can be achieved by using high-tensile steel and aluminum alloys, but the use of carbon fiber-reinforced plastics (CFRP) enables the production of the best-performing lightweight components for an automotive. Co-carbonization largely contributes to the high quality of the obtained fibers During this process, the free space within the polycyclic pitch structure is filled with relatively low-molecular-weight molecules, which avoid crack formation due to thermal contraction caused by stabilization and further carbonization. Coal tar pitch was first centrifuged with the low-cost Kerosene method, co-carbonized with pyrolysis fuel oil (PFO). Coal tar pitch (SP 30 ◦C, Posco Chemical Co., Pohang, Korea) was used as the raw material for the preparation of spinnable pitch, the precursor of the final isotropic carbon fibers. The Centrifuge Kerosene Equivalent method, consisting of melting coal tar pitch in an oven at 150 ◦C and purifying it to a liquid state, was employed to remove the insoluble precipitate by centrifugation

Preparation of the Spinnable Pitch

Purification of Coal Tar Pitch

Characteristics of Spinnable Pitch from Purified Coal Tar Pitch and PFO

Characteristics of Pitch Fibers from Purified Coal Tar Pitch and PFO

Conclusions