Effects of the molecular structure from pitch fractions on the properties of pitch‐based electrospun nanofibers

Abstract

Mesophase pitch was separated into different pitch fractions to investigate the effect of pitch fractions on the properties of their nanofibers prepared by electrospinning. The evolution of different pitch fractions‐derived nanofibers during stabilization and carbonization were explored, and the properties of the resultant carbon nanofibers (CNFs) as electrode materials for supercapacitor were compared. Results indicated that the hexane insoluble‐toluene soluble (HI‐TS) and toluene insoluble‐tetrahydrofuran (THF) soluble (TI‐THFS) fractions had good spinnability due to their narrow molecular weight distribution. Moreover, compared with HI‐TS and THF insoluble (THFI), TI‐THFS consisted of appropriate aromaticity and branched alkyl groups which promoted the stabilization and carbonization behaviors of its nanofibers, resulting in maintaining ideal fiber morphology of TI‐THFS‐derived nanofiber due to the mitigation of their exothermic reactions. Meanwhile, the TI‐THFS‐derived CNFs presented the highest surface area of 543 m2 g−1 and exhibited an excellent specific capacitance of 167 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte.

Synthesis of Carbon Nanofibers Film from Coal Liquefaction Residues: Effect of HNO3 Pretreatment

“…According to Figure S3, the L-CLRPA/PAN film has a higher O and N content and a lower C and H content than that of the CLRPA/PAN film. The C 1s and O 1s peaks can be devalued into five and four peaks, respectively, as shown in Figure a,b. , The specific peak site and corresponding groups are shown in Table S1. , The L-CLRPA/PAN film shows higher contents of peak 4 (carbonyl group, CO) and peak 5 (carboxyl group, COOH) (Figure d) than the CLRPA/PAN film. Conversely, peaks 1 and 4 of the O 1s exhibit a similar variation tendency (Figure e).…”

“…27,28 The specific peak site and corresponding groups are shown in Table S1. 10,17 The L-CLRPA/PAN film shows higher contents of peak 4 (carbonyl group, CO) and peak 5 (carboxyl group, COOH) (Figure 4d) than the CLRPA/PAN film.…”

“…TG-MS was used to investigate the released gas, particularly in H 2 O and CO 2 , which are the main products during the stabilization process. , As illustrated in Figure c, during the stabilization process, the amount of H 2 O released increases and then decreases, reaching a maximum of 295 °C. Below 200 °C, the H 2 O product can be assigned to H 2 O adsorbed on the surface of the samples. , For the L-CLRPA/PAN film, H 2 O evolution is lower at the temperature range 200–270 °C, which is consistent with lower H content.…”

“…Electrospinning, stabilization, and carbonization processes are used in abricating pitch-based ECFs. In general, the successful preparation of ECFs heavily depends on the spinning of the pitch and the stabilization of as-spun nanofibers . A suitable precursor for ECFs should satisfy two requirements; first, the softening point (SP) should not be lower than 273 °C because pitches cannot sufficiently stabilize in the air during an appropriate processing time, , and second, the pitch should be spinnable because the spinning stock is typically a liquid.…”

Porous Carbon Nanofibers with Heteroatoms Doped by Electrospinning Exhibit Excellent Acetone and Carbon Dioxide Adsorption Performance: The Contributions of Pore Structure and Functional Groups

“…In addition, specific surface area and pore volume are the key factors for VOC adsorption . While electrospun-activated carbon fibers are easier to obtain a large specific surface area, their fiber diameter is much smaller than that of the traditional commercial fiber. − The fibers are fabricated using polyacrylonitrile, pitch, and poly­(vinyl alcohol) as precursors commonly, followed by electrospinning, stabilization, carbonization, and activation.…”