Melt-Spinnable Polyacrylonitrile—An Alternative Carbon Fiber Precursor

Abstract

The review summarizes recent advances in the production of carbon fiber precursors based on melt-spun acrylonitrile copolymers. Approaches to decrease the melting point of polyacrylonitrile and acrylonitrile copolymers are analyzed, including copolymerization with inert comonomers, plasticization by various solvents and additives, among them the eco-friendly ways to use the carbon dioxide and ionic liquids. The methods for preliminary modification of precursors that provides the thermal oxidative stabilization of the fibers without their melting and the reduction in the stabilization duration without the loss of the mechanical characteristics of the fibers are discussed. Special attention is paid to different ways of crosslinking by irradiation with different sources. Examples of the carbon fibers preparation from melt-processable acrylonitrile copolymers are considered in detail. A patent search was carried out and the information on the methods for producing carbon fibers from precursors based on melt-spun acrylonitrile copolymers are summarized.

Study on the Morphologic and Flow State of Polyacrylonitrile Particles in a Microchannel Reactor

“…In recent years, microchannel reactor technology has been widely used in the field of chemistry and the chemical industry. − Microchannel reactors are small continuous tubular reactors composed of tiny channels. Compared with batch reactors, microchannel reactors have the advantages of a large specific surface area, fast heat and mass-transfer rates, high mixing efficiency, strong process safety, and more precise control of process parameters. − Due to these advantages, polymers synthesized by free-radical polymerization using microchannel reactors have controllable molecular weights and narrower molecular weight distributions. − However, in the PAN precipitation polymerization reaction, the reaction products can easily be deposited on the walls of the microchannel reactor. This can lead to a sharp increase in the pressure drop in the reactor and even blockage.…”

Toughening nonwoven polyacrylonitrile.carbon nanotube composite materials

“…The process has issues with temperature, as cyclization reactions can occur around 270 °C, which is below the temperature of melt processing (Chernikova, 2022). In order to use this method, the melting point has to be adjusted below the cyclization reaction temperature, which involves adding more chemical species to the system (Chernikova, 2022). That makes the overall chemistry less predictable, as more species factor in rules of mixing that can affect other properties in the system.…”