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Study on Poly (Vinyl Alcohol) Nanofibers Prepared Via Electrospinning

Author: ChangXueZuo
Tutor: YangHu
School: East China University of Science and Technology
Course: Material Chemical Engineering
Keywords: Electrospinning Polyvinylalcohol (PVA) Nanofibers Catalyst
CLC: TQ342.8
Type: Master's thesis
Year: 2011
Downloads: 188
Quote: 0
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Abstract

This article nanofibers by electrospinning Preparation of polyvinyl alcohol (PVA), PVA electrospinning process influencing factors to select the optimal conditions for preparation of PVA nanofibers. Electrospinning prepared PVA with a perfluorinated sulfonic acid resin (PFSA), as well as a blend of PVA and salts System nanofiber catalyst and its catalytic performance was measured for the synthesis of ethyl acetate. The specific results are as follows: First, using an electrostatic spinning method, a comparison of different kinds of PVA raw material (FJ1788, SH1788, GD1799) electrically spinnability the merits and fiber morphology. The results indicate that different types of PVA obtained spinning solution in the viscosity, conductivity and surface tension, are very different. Under the same conditions, the electrically spinnability merits of the three materials were FJ1788 GT; the SH1788 GT; GD1799. And after blending different concentrations of DMAc, can effectively improve the the GD1799 electrical spinnability, add the superiority of [nanofiber morphology obtained after 20 wt% of DMAc. Next to pure water the solvent, PVAFJ1788 as raw materials, different spinning conditions on the PVA fiber morphology and diameter distribution. The results show that the PVA concentration increases, the viscosity of the spinning solution is increased, the conductivity increases, the equilibrium surface tension is decreased slowly, better fiberization of 7wt% to 11wt% of the concentration range of the PVA, an average fiber diameter from 128 ~ 210nm gradually increases. With the operating voltage 10kV ~ 18kV range changes, the fiber morphology gradually becomes good, the fiber diameter is gradually reduced, the diameter distribution is narrowed. Curing distance 5cm to 20cm inside the change, the average fiber diameter first decreases and then increases the process, and the average diameter of 15cm when minimum. The spinning flow is too low or too high is not conducive to the forming of the fiber, and 0.3 ml / h under the conditions obtained nano-fiber morphology Jiaoyou. Then, using the electrospinning prepared PVA-PFSA nanofiber catalyst. Were investigated PFSA the addition amount of the operation voltage, and the spinning flow and curing the influence of the distance on the morphology and diameter distribution of the PVA-PFSA nanofibers, under different conditions and experiment for the synthesis of ethyl acetate, obtained nanofibers catalytic performance were determined. The results indicate that the influence of the addition amount of the fiber morphology and an average diameter size of the impact on catalytic properties than PFSA. Increase the voltage, curing distance can be effective in improving the PVA-PFSA fiber morphology increase flow after the fiber morphology worse, and catalytic performance relative decline. , The catalytic effect is substantially no effect on the catalyst can be reused 3 times. Finally, the use of electrostatic spinning prepared PVA-salt nanofiber catalyst. Were selected sodium bisulfite, potassium persulfate as the blended salts. PVA-salt system nanofibers catalyst shows good catalytic effect, and PVA (9wt%) / NaHSO4 (2wt%) / DMAc (35wt%)-H2O (54wt%), the spinning of the spinning liquid formulations Conditions for 16kV/15cm/0.3ml/h obtained nanofiber catalyst, catalytic ethyl acetate conversion rate reached about 35%. But the spinning process is unstable and difficult to control. Catalyst can be reused three times after catalytic effect of a slight decline.

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