Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

Manufacturing, Characterisation and Mechanical Analysis of PAN Membranes

Version 1 : Received: 11 September 2020 / Approved: 12 September 2020 / Online: 12 September 2020 (09:27:39 CEST)
Version 2 : Received: 6 October 2020 / Approved: 7 October 2020 / Online: 7 October 2020 (09:20:10 CEST)
Version 3 : Received: 14 October 2020 / Approved: 15 October 2020 / Online: 15 October 2020 (16:48:45 CEST)

A peer-reviewed article of this Preprint also exists.

Tüfekci, M.; Durak, S.G.; Pir, İ.; Acar, T.O.; Demirkol, G.T.; Tüfekci, N. Manufacturing, Characterisation and Mechanical Analysis of Polyacrylonitrile Membranes. Polymers 2020, 12, 2378. Tüfekci, M.; Durak, S.G.; Pir, İ.; Acar, T.O.; Demirkol, G.T.; Tüfekci, N. Manufacturing, Characterisation and Mechanical Analysis of Polyacrylonitrile Membranes. Polymers 2020, 12, 2378.

Journal reference: Polymers 2020, 12, 2378
DOI: 10.3390/polym12102378

Abstract

To investigate the effect of Polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes PAN and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries, but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.

Subject Areas

mechanical characterization; foams; ultrafiltration membrane; finite element method; non-linear deformations

Comments (1)

Comment 1
Received: 7 October 2020
Commenter: Mertol Tufekci
Commenter's Conflict of Interests: Author
Comment: Some key results are presented in abstract, lines 26-30.
The names of the softwares are mentioned in line 211.
The standard deviations are added in Table 2, on page 6. As it is declared in Figure 1 (page 7), PAN 1 membranes only consist of pure PAN material, but PAN 2 membrane also consists PVP polymer to increase the porosity of membrane and membrane flux. So lower contact angle is also an indicator of that advantages and it is an expected result (Page 6, lines 264-271). Besides, new references are added at line 271.
The pure water flux measurement is repeated. Thus, the flux values of membranes recalculated and changed in Figure 1 on page 7. However, a small decrease after 2500 min. can be still observed. Because of the applied pressure, the pores of the membrane are compacted and a small decrease can be accepted as normal behaviour. The interpretation and a reference are added at line 267.
FTIR results are rechecked. Since PAN 1 values were drawn without paying attention to the scale, they were not seen in detail. When the graph is replotted, the values are seen more clearly and overall it appears alright. Figure 4 is replaced with the new version. New comments and references are added between 286 298.
Section 4.2 is divided into several subsections. The headings are as follows:
4.2. Numerical Study: Modelling of Membranes
4.2.1. Investigation of Membranes Made of PAN 1
4.2.2. Investigation of Membranes Made of PAN 2
4.2.3. Investigation of Elliptical Membranes with Different Aspect Ratios
4.2.4. Final Remarks
4.3. Numerical Study: Modelling of Representative Elements
A paragraph commenting on the mechanism that influences the mechanics of these membranes are inserted between lines 394 and 400.
The conclusions section is shortened.
Typos are corrected and a revision is done on the use of the English language.
According to flux, porosity and contact angle results, it is assumed that the pore size of the PAN 2 membrane is larger than PAN 1. To support these results, the SEM images are to the surface SEM images which display the issue more clearly (Figure 2). As is can be seen in Figure 2, the pore difference of membranes are more clear now. So as expected the large pores of PAN 2 membranes can be seen clearly. Because the addition of pore agents like PVP, make larger pores.
The AFM images are replaced with more clear ones (Figure 3).
Representation peak need to be assigned to the functional group in the polymer which is not done.Thank you for the correction. Figure 4 is replotted, corrected and interpreted. The FTIR spectrum of membranes explained more clearly.

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