This paper reviews recent developments in carbon fibers. Intensive studies focus on relationships among processing conditions, chemical/physical structures and tensile properties of polyacrylonitrile and meso-phase pitch based carbon fibers. Carbon fibers with specific geometry, such as hollow, porous, and patterned, have been fabricated for specific applications. Additionally, carbon nanotubes (CNTs), which have excellent mechanical properties, have been processed into macroscopic continuous fibers. Incorporating CNTs in precursor fiber also improves tensile strength and modulus of the resultant carbon fiber. Although extensive studies have been conducted for improving carbon fiber tensile strength and modulus as well as for reducing their production cost, these issues remain amongst the main challenges for broadening their applications.

Recent Progress in Fabrication, Structure, and Properties of Carbon Fibers

Due to their lightweight and excellent toughness, carbon fiber (CF) and its reinforced thermoplastic composites are suitable for high-performance applications such as aerospace, aviation, automotive and sport equipments. In this study, comprehensive detail is provided on the production of carbon fiber, its various forms and geometry and their corresponding effects on the mechanical properties of CF and its reinforced polypropylene (PP) and polyethylene (PE) composites. Here we discuss extensively various methods reported in literature on improving the interfacial fiber-matrix adhesion and dispersion in order to achieve better mechanical properties for such composites.

Progress in Carbon Fiber and Its Polypropylene- and Polyethylene-Based Composites

Middle-modulus high-strength polyacrylonitrile-based carbon fiber, and preparation method thereof

Fatigue assessment of welded joint is still far from being completely solved now, since many influencing factors coexist and some important ones should be considered in the developed life prediction models reasonably. Thus, such influencing factors of welded joint fatigue are firstly summarized in this work; and then, the existing life prediction models are reviewed from two aspects, i.e., uniaxial and multiaxial ones; finally, significant conclusions of existing experimental and theoretical researches and some suggestions on improving the fatigue assessment of welded joints, especially for the low-cycle fatigue with the occurrence of ratchetting, are provided.

Review on fatigue life prediction models of welded joint

The rational integration of multiple functional units into heterogeneous materials to improve catalytic performance is highly desirable for CO2 value-added processes. Herein, a catalyst composed of porous carbon matrix with atomically dispersed Lewis acid sites (i.e., AlO5 motifs) and imidazolium-based poly(ionic liquid)s (denoted as [email protected]) was fabricated. Compared with pure Al-O-C or PILs, the optimized [email protected] exhibits superior catalytic performance (>90% yield) towards cycloaddition reaction of CO2 and epoxides in the absence of solvent and co-catalyst. The enhanced activity of [email protected] is attributed to the synergistic effect among the uniform N sites (Lewis base sites) and abundant bromide anions (nucleophilic agents) in the PILs network, as well as the atomically dispersed Al sites (Lewis acid sites) in the Al-O-C matrix. This work provides an advanced [email protected] catalyst for constructing a neat catalytic system towards CO2 fixation. 

Atomically Dispersed Lewis Acid Sites Meet Poly(ionic liquid)s Networks for Solvent-free and Co-catalyst-free Conversion of CO2 to Cyclic Carbonates

The invention relates to a polyacrylonitrile-based hollow carbon fiber precursor and a preparation method thereof. The polyacrylonitrile-based hollow carbon fiber precursor of the invention can be used for preparing polyacrylonitrile-based hollow carbon fibers. An acrylonitrile binary copolymerization system containing itaconic acid or an acrylonitrile ternary polymerization system containing itaconic acid and methyl acrylate is adopted for spinning by a wet spinning process matched with a circular arc slit spinneret plate, and multiple filament bundles of the hollow carbon fiber precursor can be obtained, wherein the dimension of the outer diameter and the structure of the precursor meet the requirement of a conventional preoxidation carburizing process for precursor fibers, and the groove structure on the surface of the fiber is favorable for improving the interface performance of composite materials.

Polyacrylonitrile-based hollow carbon fiber precursor preparation method

High strength polyacrylonitrile-base carbon fibers having structured surface grooves, and preparation method thereof

Preparation method of polyacrylonitrile pre-oxidation fiber and carbon fiber

The invention relates to an acrylonitrile polymer composite prepared through polyacrylonitrile-based carbon fibers, carbon fiber precursors and carbon fibers prepared through the polymer composites, as well as the preparation methods for the carbon fiber precursors and carbon fibers. In particular, the polymer composite of the invention comprises a acrylonitrile-containing composite and an alkaline compound, the carbon fiber precursors and carbon fibers prepared through the polymer composite, and the preparation methods. With the methods of the invention, precursor fibers with high density and regular surface groove structures can be obtained without increasing the spinning draw-down ratio, or even under the condition of reducing the draw-down ratio appropriately; the volume density of precursor fibers can reach 1.19g/cm3 or more; through preoxidized carbonization, the precursor fibers can obtain high-performance carbon fibers with volume density exceeding 1.78g/cm3, the tensile strength surpassing 4.9GPa, and the tensile modulus greater than 230GPa.

Li Changqing

Papers

Middle-modulus high-strength polyacrylonitrile-based carbon fiber, and preparation method thereof

Polyacrylonitrile-based hollow carbon fiber precursor preparation method

High strength polyacrylonitrile-base carbon fibers having structured surface grooves, and preparation method thereof

Preparation method of polyacrylonitrile pre-oxidation fiber and carbon fiber

Acrylic nitrile-containing polymerization composition for carbon fibre and preparation thereof