科创中国

Hypothesis: Carbon based nanofibrous materials are considered to be promising sorbents for the CO₂ capture and storage. However, the precise control of porous structure with flexibility still remains a challenging task. In this research, we report a simple strategy to develop tin oxide (SnO₂) embedded, flexible and highly porous core-shell structured carbon nanofibers (CNFs) derived from polyacrylonitrile (PAN)/polyvinylidene fluoride (PVDF) core-shell nanofibers. Experiment: PAN/PVDF core-shell solutions were electrospun using co-axial electrospinning process. The as spun PAN core, and PVDF shell, with an appropriate amount of SnO₂, fibers were stabilized followed by carbonization to develop SnO₂ embedded highly porous and flexible core-shell structured CNFs. Findings: The optimized CNFs membrane shows a prominent CO₂ capture capacity of 2.6 mmol g⁻¹ at room temperature, excellent CO₂ selectivity than N₂, and a remarkable cyclic stability. After 20 adsorption-desorption cycles, the CO₂ capture capacity retains >95% of the preliminary value showing the long-term stability and practical worth of the final product. The loading of SnO₂ nanoparticles in the carbon matrix not only enhanced the thermal stability of the precursor nanofibers, their surface characteristics, and porous structure to capture CO₂ molecules, but also improves the flexibility of the CNFs by serving as a plasticizer for single-fiber-crack connection. Meaningfully, the flexible SnO₂ embedded core-shell CNFs with excellent structural stability can prevail the limitations of annihilation and collapse of structures for conventional adsorbents, which makes them strongly useful and applicable. This research introduces a new route to produce highly porous and flexible materials as solid adsorbents for CO₂ capture.

Nadir Ali;Aijaz Ahmed Babar;Yufei Zhang;Nousheen Iqbal;Xianfeng Wang;建勇 俞;彬 丁

Journal of Colloid and Interface Science

2020-2-15

Frequent oil spills and the ever-growing discharge of industrial oily wastewater seriously threaten ecosystems and human safety and result in huge economic loss, which has stimulated researchers to explore advanced oil/water separation materials. Electrospun nanofibrous membranes, featuring tunable wettability, good flexibility, high porosity, and outstanding pore connectivity, have received increasing attention. In this review, we aim to present the design and fabrication of electrospun flexible nanofibrous membranes with special wettability for oil/water separation. This review focuses on the discussion of various electrospun flexible membranes, assorted into three categories, including polymer-based membranes, ceramic-based membranes, and carbon-based membranes. In each type, the representative studies, fabrication techniques, and the synergistic effect among the membrane structure, selective wettability, and oil/water separation performance are discussed in detail. Finally, future perspectives and challenges in this promising field are highlighted.

Jichao Zhang;Feng Zhang;Jun Song;Lifang Liu;Yang Si;建勇 俞;彬 丁

Journal of Materials Chemistry A

2019

Damping behaviors and miscibility between a polar polymer (CPE) and an organic small molecule (AO-18) are mainly discussed in this paper. It is well-known that mixing two partly compatible polymers can produce a material with a wide range of the glass transition temperature (Tg) and thus good damping behavior. In this paper, since CPE and AO-18 are partially miscible, adding AO-18 to CPE causes T_g of the mixture shifts to higher temperature, and the relaxation of AO-18 appears when AO-18 content is high in CPE/AO-18 alloy, similar to two partly compatible polymers. The damping properties around CPE glass transition are greatly improved compared with pure CPE, which can be attributed to the hydrogen bonds between CPE and AO-18 in CPE/AO-18 hybrids.

Jitao Liu;建勇 俞;Shanyuan Wang

2002

Rapid formation of PTFE-like polymer nanocrystals was achieved by a novel synthesis method-oriented plasma polymerization (OPP) at atmospheric pressure. The entire process was completed within a short period of time ranging between a few seconds to several minutes through dielectric barrier discharge (DBD) at atmospheric pressure. The surface morphology of the coated organic crystal film was observed through scanning electronic microscope (SEM) and different morphology nanocrystals were found such as nanorods and nanotubes. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed the single-crystalline phase of these nanocrystals. The sizes of the nanosingle crystals were from 10 nm to 1 μm. The effects of discharge conditions such as discharge time, ratio of the monomer to carrier gas and power on the nanocrystalline morphology and crystallinity were investigated. As a result, the physical morphology and structures could be controlled through the conditions of the oriented plasma polymerization to some extent. This novel polymerization method opened a new way to nanofabricate polymeric crystallines fast and effectively.

Ying Guo;Jing Zhang;Jinzhou Xu;建勇 俞

Applied Surface Science

2008-3-30

Nanofibers produced by electrospinning are already being used in a vast array of products in many industries. However, the volume of production of nanofibers has been being a bottleneck restricting their applications. In this work we reported a novel method to fabricate continuous and uniform nanofibers by electrospinning using an aerated polymer solution in an electric field. Multiple jets, which were a prerequisite for increasing the volume of production, were found in this electrospinning process. The morphology of the deposited fibers was straight, coiled and helix observed by a scanning electron microscope (SEM) and an optical microscopy. The results showed that the product of this process was similar to that of a traditional electrospinning process and illustrated a good prospect of application.

Y. Liu;J. H. He;建勇 俞

Journal of Physics: Conference Series

2008-2-1

Electrospinning is a simple but powerful method for making nanofibers that can then be collected to create porous mats. We expand the range of this technique by making nanofibers from macromolecules with a molecular weight of 3,000,000, namely polyethylene oxide) (PEO). Gelation of PEO blocks its spinning by traditional electrospinning. PEO was mixed with pure alcohol, and in specific concentration 10 wt % and under vibration condition, the mixed solution behaves like polymers for electrospinning, the average diameter of the obtained nanofibers is about 100 nm.

Yu Qin Wan;Ji Huan He;建勇 俞;Yue Wu

Journal of Applied Polymer Science

2007-3-15

This paper is concerned with a study of compression force measured by smart cellular textile composites integrated with fiber Bragg grating (FBG) sensors. The novel design of the cellular textile composite structures integrated with FBG sensors is reported. Unit cells of a cylindrical composite shell are fabricated from glass and polyester woven fabrics and epoxy, and are used to measure compression loads. When the composite shell unit is under pressure, the axial strain induced in the FBG sensor can be determined by the Bragg wavelength shift obtained from an optic spectrum analysis. A theoretical analysis of the fiber's axial strain focuses on compression load. The influences of environmental tem perature, thickness, and effective moduli of the composites, and position and direction of the FBG sensors are discussed. The sensitivity of this device is 0.42 nm/N (for the polyester composite) and 0.29 nm/N (for the glass composite), and the measurement range is 0-2.1 N (PET) and 0-1.3 N (glass), respectively.

Yang Bin Yang;Ming Tao Xiao Ming Tao;建勇 俞;ho hoilui ho

Textile Reseach Journal

2004-4

In this paper, the fractal characteristics of goose down assembly are described by determining the pore area fractal dimension and the tortuosity fractal dimension. The goose down assembly, filled with mass of down fibers and pores, is loose and ductile. The pores are varying shapes and sizes, and distribute unevenly. Firstly, micro computed tomography is used to observe the internal microstructure of down assembly without destructing the original assembly shape. The derived computed tomography images of down assemblies with various volume fractions are then treated by two-value method. The measurement verifies that the porous structure of down assembly possesses typical fractal characteristic, and the pore area fractal dimensions D_f are determined by the box counting method. According to the capillary principle the tortuous flow path in down assembly is simulated, and the fractal dimension of the tortuous flow path D_T is also calculated by the same way. The results indicate that the pore area fractal dimensions decrease and the tortuosity fractal dimensions increase gradually as the volume fractions V_f of the assembly increase.

Jin Gao;Xianwen Fu;建勇 俞

Journal of Computers

2012

In contrast to conventional preforming techniques, additive manufacturing features direct and layer-by-layer fabrication, which provides viable new capabilities for the fabrication of reinforced composites. In this article, we explore the microstructural design as well as additive manufacturing and characterization of 3D orthogonal, short carbon fiber/acrylonitrile-butadiene-styrene (ABS) preforms and composite. First, an array of 3D orthogonal preforms is designed based on topological consideration and validated by fused filament fabrication of pure ABS wire; high fidelity between models and preforms is accomplished. Then, short carbon fibers are introduced into the designed 3D orthogonal preforms as reinforcement, using a short carbon fiber/ABS wire. Lastly, the compressive behavior of a 3D orthogonal, short carbon fiber/ABS preform and that of its silicone infused composite are characterized. The preform design methodology developed in this research as well as the preliminary effort made in composite fabrication and characterization demonstrates the feasibility of additive manufacturing of 3D orthogonal preform based fiber composites.

Zhenzhen Quan;Zachary Larimore;Amanda Wu;建勇 俞;小红 覃;Mark Mirotznik;Jonghwan Suhr;Joon Hyung Byun;Youngseok Oh;Tsu Wei Chou

Composites Science and Technology

2016-4-1

We have successfully prepared the blend bio-fibers from cellulose and soy protein isolate (SPI) in NaOH/thiourea/urea aqueous solvent by coagulating with 10 wt % H₂SO₄/12.5 wt %Na₂SO₄aqueoussolution.The structure and properties of the as-prepared blend fibers were characterized by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy (SEM) and tensile testing. The values of tensile strength and elongation at break for the blend bio-fibers with 10 wt % of W_SPI reached 1.86 cN/dtex and 10.3%, respectively.

Shuai Zhang;Yuan Tian;Yi Jie Shen;Fa Xue Li;建勇 俞

2009