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RISS 인기검색어
- 검색키워드
- 저자 : Vahid Mottaghitalab (검색결과 7 건)
- 무료
- 기관 내 무료
- 유료
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A study on electrospinning of polyacrylonitrile nanofibers
Vahid Mottaghitalab,Akbar Khodaparast Haghi 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1
Aligned and molecularly oriented Polyacrylonitrile (PAN) nanofibers were prepared using a non-conventional approach. Various take up velocity of rotating drum was examined for increasing of productivity, alignment and mechanical properties of nanofibers. Impressive techniques like Raman spectroscopy were utilized for characterization of nanofibers.
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A new approach for optimization of electrospun nanofiber formation process
Akbar Khodaparast Haghi,Mohammad Ziabari,Vahid Mottaghitalab 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1
Precise control of fiber diameter during electrospinning is very crucial for many applications. A systematic and quantitative study on the effects of processing variables enables us to control the properties of electrospun nanofibers. In this contribution, response surface methodology (RSM) was employed to quantitatively investigate the simultaneous effects of four of the most important parameters, namely solution concentration (C), spinning distance (d),applied voltage (V) and volume flow rate (Q), on mean fiber diameter (MFD) as well as standard deviation of fiber diameter (StdFD) in electrospinning of polyvinyl alcohol (PVA) nanofibers.
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Simulated image of electrospun nonwoven web of PVA and corresponding nanofiber diameter distribution
Akbar Khodaparast Haghi,Mohammad Ziabari,Vahid Mottaghitalab 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
Fiber diameter is the most important characteristic in electrospun nonwoven webs. Understanding how it is influenced by the electrospinning parameters is essential to produce webs with desired characteristics. In this contribution, Direct Tracking method for measuring electrospun fiber diameter is described. To evaluate the accuracy of the technique, a simulation algorithm for generating webs with known characteristics was employed. To verify the applicability of the method on real samples, an electrospun polyvinyl alcohol (PVA) mat, as a representative of real webs, was used. Since the Direct Tracking method uses a binary image as its input, local thresholding was applied to segment the SEM micrograph of the electrospun web. The results indicate that the method could be used successfully for determining fiber diameter in electrospun nonwoven webs.
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Distance transform algorithm for measuring nanofiber diameter
Akbar Khodaparast Haghi,Mohammad Ziabari,Vahid Mottaghitalab 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
This paper describes a new distance transform method used for measuring fiber diameter in electrospun nanofiber webs. In this algorithm, the effect of intersection is eliminated, which brings more accuracy to the measurement. The method is tested by a series of simulated images with known characteristics as well as some real webs obtained from electrospinning of PVA. Our method is compared with the distance transform method. The results obtained by our method were significantly better than the distance transform, indicating that the new method could successfully be used to measure electrospun fiber diameter
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The electroless plating of Cu-Ni-P alloy onto cotton fabrics
Akbar Khodaparast Haghi,Arezoo Afzali,Vahid Mottaghitalab,Mahmood Saberi Motlagh 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4
The objective of this study is to apply the electroless plating of Cu-Ni-P alloy on cotton fabrics to the preparation of conductive fabrics. The alloy composed of infinit small amount of nickel and phosphorus particle originated from sodium hypophosphite and nickel sulphate respectively as reducing agent and hypophosphite oxidation accelerator. Electroless plating of Cu-Ni-P alloy on cotton fabrics and effect of plating on the physical and mechanical properties of alloy coated fabrics as well as electromagnetic interference (EMI) shielding effectiveness were reported in detail. In this research highly washing and abrasion durable conductive fabrics obtained with supreme shielding effectiveness.
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Evaluation of electrospun nanofiber pore structure parameters
Akbar Khodaparast Haghi,Mohammad Ziabari,Vahid Mottaghitalab 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.4
Nanofibers produced by electrospinning method are widely used for drug delivery, as tissue scaffolding materials and filtration purposes where specific pore characteristics are required. For continued growth in these areas, it is critical that the nanofibers be properly designed for these applications to prevent failure. Most of the current methods only provide an indirect way of determining pore structure parameters and contain inherent disadvantages. In this study, we developed a novel image analysis method for measuring pore characteristics of electrospun nanofiber webs. Five electrospun webs with different pore characteristics were analyzed by this method. The method is direct, very fast, and presents valuable and comprehensive information regarding pore structure parameters of the webs. Two sets of simulated images were generated to study the effects of web density, fiber diameter and its variations on pore characteristics. The results indicated that web density and fiber diameter significantly influence the pore characteristics, whereas the effect of fiber diameter variations was insignificant.
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Conductive chitosan/multi walled carbon nanotubes electrospun nanofiber feasibility
Zahra Moridi Mahdieh,Akbar Khodaparast Haghi,Vahid Mottaghitalab,Negin Piri 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.1
The current study focuses on the electrospinning of chitosan (CHT)/multi walled carbon nanotubes (MWNTs)composite nanofiber using a highly stable dispersion. The acetic acid (1-100%) and trifluoroacetic acid/dichloromethane (TFA/DCM 70 : 30) was tested as solvent, and the TFA/DCM (70 : 30) is most preferred for fiber formation process with acceptable electrospinnability. Moreover, a new protocol was used to establish proper technique for preparation of electrospinning solution. FT-IR spectroscopy utilized to infer the extent of interaction between CHT polymer chain and MWNT filaments. A quite simple technique was employed to show the stability of electrospinning solution before nanofiber formation process. Scanning electronic microscope (SEM) was employed to show the influence of spinning parameters on surface morphology of electrospun fiber. Under optimized condition, homogeneous and beadfree CHT/MWNTs nanofibers and known physical characteristics were prepared. The formation of conducting nanofibers based on CHT nanocomposites can be considered as a significant improvement in electrospinning of CHT/CNT dispersion. The direct outcome of the current study includes the homogeneous CHT/MWNTs nanofibers with an average diameter of 275 nm and a conductivity of 9×10−5 S/cm. These results are extremely important for further investigation regarding biomedical applications.
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