Fengwen Zhao

Beijing University of Chemical Technology

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Yong Liu

Beijing University of Chemical Technology

Huilin Yuan

Collaborative Innovation Center of Chemistry for Energy Materials

Yuexing Liu

University of South China

Fuzhou Feng

Air Force Engineering University

Jianming Zhang

Qingdao University of Science and Technology

Jianmin Liu

Fujian Normal University

Weimin Yang

Beijing University of Chemical Technology

Jianyun He

Beijing University of Chemical Technology

Weimin Yang

Beijing University of Chemical Technology

Yuyun Zhang

Sichuan University of Science and Engineering

Cooperative Institutions

Beijing University of Chemical Technology

Qingdao University of Science and Technology

Shandong University

Henan University of Technology

Chinese Academy of Sciences

Collaborative Innovation Center of Chemistry for Energy Materials

FORCE Technology (Norway)

University of South China

Air Force Engineering University

Chinese People's Armed Police Force Engineering University

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Solvent-free preparation of polylactic acid fibers by melt electrospinning using umbrella-like spray head and alleviation of problematic thermal degradation

Journal of the Serbian Chemical Society (2012)

Yong Liu Fengwen Zhao Chi Zhang Jianming Zhang Weimin Yang

Melt electrospinning is an even simpler and safer method compared with the solution electrospinning in the production of ultra-fine fibers. Polylactic acid (PLA) is a biodegradable and resorbable aliphatic ester that has received significant attention in recent years. PLA is easily degradable at high temperature in the process of melt electrospinning. High efficient fibers were made using our designed umbrella-like spray head spinning facility in this work. To find how to alleviate the problematic degradation and what factors could be relevant to degradation, temperature, relative molecular mass, Differential Scanning Calorimeter and X-ray Diffraction patterns before and after spinning were investigated and compared with each other. Results showed that fibers were facile shorten and fractured when spun at 245?C while the relative molecular mass of PLA fibers decreased markedly as compared with that spun at 210?C. To hinder the degradation, couple of experimental efforts were implemented with adding antioxidants, raising spinning voltage, lowering temperature, and reducing residence time. After such efforts, it was observed that the relative molecular mass of the PLA fibers was higher than those without inputting any efforts. The effect of antioxidant 1010 was found the most promising on the alleviation of PLA problematic thermal degradation.

Polylactic Acid

Electrospinning

Degradation

10.2298/jsc110711027l

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APPLICATION RESEARCH OF GA AND SOFM ON PATTERN CLASSIFICATION FOR A CERTAIN DIESEL ENGINE

한국소음진동공학회 국제학술발표논문집 (2008)

Fuzhou Feng Yinmao Zhao Fengwen Zhao Jianmin Liu

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An Ocean Bottom Seismic Data Recorder

Chinese Journal of Geophysics (2003)

Anmin Shao Yuyun Zhang Fengwen Zhao

Abstract An ocean bottom seismic data recorder is a broadband digital instrument of large dynamic range, and it can be used for recording the seismic data on the ocean bottom or in remote land areas. It is a compact, light‐weight and easy operation, adopting two buffer memories to control the PC/104 embedded computer, so that it can record the seismic data continuously over long time at a low‐power dissipation. The key component of the recorder is the PC/104 embedded computer, which ensures the reliable operation of the recorder. It uses a hard disk to store data. The 2GB hard disk can hold 1.9998GB seismic data. The time length of recording the seismic data is decided by the sampling rate.

Data logger

Ocean bottom

10.1002/cjg2.346

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Effect of polar additives on melt electrospinning of nonpolar polypropylene

Journal of the Serbian Chemical Society (2013)

Chen Zhi-Yuan Jianyun He Fengwen Zhao Yuexing Liu Yong Liu

Melt or solution electrospinning is an effective and direct technique for producing nanoscale fibers. Polypropylene (PP) cannot be easily dissolved at ambient temperature. Thus, it was commonly electrospun in melt state. However, compared with solution electrospun fibers, melt electrospun PP fibers are more uneven with bigger diameters. To remedy this problem, polar additives, namely, stearic acid and sodium stearate were added into pure PP. The effects of the additives were investigated. Results showed that contrasting to those of pure PP, the fiber diameter of PP with 8 wt% stearic acid decreased by 69.3 % (from 5.4 ?m to 1.6 ?m). The smallest fiber diameter was 600 nm and the smallest average fiber diameter was 1.8 ?m when the sodium stearate contents were 10 wt% and 8 wt%, respectively. The addition of polar compounds could alter not only the diameters of PP microfibers, but also the distribution of diameters, the processing current, and even the thermal properties of fibers. The microcosmic mechanisms for these changes were interpreted.

Stearic acid

Microfiber

Electrospinning

Polypropylene

Stearate

10.2298/jsc130702150z

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Orthogonal design study on factors affecting the degradation of polylactic acid fibers of melt electrospinning

Journal of Applied Polymer Science (2012)

Fengwen Zhao Yong Liu Huilin Yuan Weimin Yang

Abstract Melt electrospinning is a much simpler and safer method in the production of ultra‐fine fibers compared with solution electrospinning. However, high‐spinning temperature usually leads to serious degradation of polymer materials. In determining factors that affect the relative molecular mass of polylactic acid (PLA) fibers during melt electrospinning, an orthogonal design method was used to examine the influence of melting temperature, spinning distance, and species and content of antioxidants. Results showed that antioxidant content at the present three levels (i.e., 0.1%, 0.3%, and 0.5%) has the most considerable effect on the relative molecular mass of PLA fibers. Error analysis showed that changes in temperature, distance, and antioxidant content influence the experiment's results significantly. All interaction effects were larger than those of the single factor in the experimental results. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Electrospinning

Polylactic Acid

Degradation

10.1002/app.36426

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Citations (30)