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# Acetylated Wheat Starch Membranes: Permeability Measurements

Catherine Joly, Christophe Bliard, Eliane Espuche, M. Escoubes

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## To cite this version:

Catherine Joly, Christophe Bliard, Eliane Espuche, M. Escoubes. Acetylated Wheat Starch Membranes: Permeability Measurements. ISPAC 10, Stephen T. Blake, Aug 1997, Toronto, Canada. pp.35-36. hal-02117725

HAL Id: hal-02117725

https://hal.science/hal-02117725

Submitted on 2 May 2019

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Distributed under a Creative Commons Attribution 4.0 International License
INTERNATIONAL

SYMPOSIUM ON

POLYMER

ANALYSIS AND

CHARACTERIZATION

AUGUST 10-13, 1997

University of Toronto
Toronto, Ontario
Canada
TENTH INTERNATIONAL
SYMPOSIUM ON POLYMER
ANALYSIS AND
CHARACTERIZATION

August 10-13, 1997

University of Toronto
Toronto, Ontario
CANADA

GOVERNING BOARD MEMBERS

Dr. Stephen T. Balke*
Department of Chemical Engineering
University of Toronto
Toronto, Ontario, Canada

Dr. Howard Barth**
Du Pont Experimental Station
Wilmington, Delaware, USA

Dr. Guy C. Berry
Department of Chemistry
Carnegie Mellon University
Pittsburgh, PA, USA

Dr. H.-J. Cantow
University of Freiburg
Freiburg, Germany

Dr. Oscar Chiantore
Department of Chemistry
University of Torino
Torino, Italy

Dr. John V. Dawkins
Chemistry Department
Loughborough University of Technology
Loughborough, Leicestershire
Great Britain

Dr. Nikos Hadjichristidis
Division of Chemistry
University of Athens
Athens, Greece

Dr. Josef Janca
Université de La Rochelle
La Rochelle, France

Dr. Pavel Kratochvil
Academy of Sciences of the Czech Republic
Prague, Czech Republic

Dr. Sadao Mori
Faculty of Engineering
Mie University
Mie, Japan

Dr. Petr Munk
Department of Chemistry
University of Texas at Austin
Austin, Texas, USA

Dr. Marguerite Rinaudo
CERMAV-CNRS
Grenoble, France

* ISPAC-10 Chair, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada, M5S 3E5, (416) 978-7495

** Program Chairman, Du Pont Co., Experimental Station, Bldg. 228, Wilmington, DE 19898, (302) 695-4354
28 Brito, Z., Torrealba, V., Sánchez, G., Hernández, L., Kinetic Characterization in DGEBA/ETDA with Mono and Bimetallic Fillers from Thermogravimetric Curves

29 Maccone, P., Apostolo, M., Molecular Weight Distribution of Fluorinated Polymers with Long Chain Branching

30 Maccone, P., Dynamic Light Scattering of Concentrated Solutions of Perfluoropolyethers, Polyisocyanate and Apolar Solvent in a Ternary System

31 D'Agnillo, L., Soares, J.B.P., Penlidis, A., A Hierarchical Data Analysis of a Replicate Experiment in Polyethylene Synthesis with High-Temperature Gel Permeation Chromatography

32 Soares, J.B.P., Abbott, R.F., Willis, J.N., Liu, X., New Methodologies for Studying Multiple-Site-Type Catalysts for the Copolymerization of Olefins

33 Ohtani, H., Nonobe, T., Tsuge, S., Kitayama, T., Hatada, K., Stereoregularity of Poly(methyl methacrylate)s Studied by Pyrolysis-Gas Chromatography/Mass Spectroscopy

34 Pagé, J.Y.S.D., Bonin, H.W., Bui, V.T., Bates, P.J., Viscoelastic Analysis of Irradiated Polymer Resins (Polycarbonate, Polysulfone and Polyetheretherketone)

35 Joly, C., Bliard, C., Espuche, E., Escoubès, M., Acetylated Wheat Starch Membranes: Permeability Measurements

36 Laignel, B., Bliard, C., Bourg, S., Nuzillard, J.M., Massiot, G., Kinetics Study of Glucose Acetylation in Starch Polymers by Quantitative ¹³C NMR Spectroscopy

37 Vancso, G.J., Pearce, R., Real-Time Imaging of Melting and Crystallization in Poly(Ethylene Oxide) by Atomic Force Microscopy with Lamellar Resolution

38 Tanaka, M., Shimbo, K., Yamada, T., Ohfusa, Y., Taguchi, M., Suzuki, H., MacFarlane, J.D., Development of Downsized Columns and System for GPC Analyses

39 Fan, X-D., Deng, Y., Waterhouse, J., Pfromm, P., Synthesis and Characterization of Soy-Based Copolyamides Consisting of Amino Acids or Soy-Protein

40 Wong, W.S., Schmidt, S., Gillespie, D., Application of SEC for the Characterization of Cellulose Materials
# Acetylated wheat starch membranes : Permeability measurements

C. Joly¹), C. Bliard¹), E. Espuche²), M. Escoubès²)

1) Laboratoire de Pharmacognosie, UPRESA 6013 CNRS, Université de Reims Champagne Ardenne, CRPB Bât 18, Moulin de la housse, BP 1039, 51 097 Reims Cedex 2 - France - 2) Laboratoire d'Etudes des Matériaux Plastiques et des Biomatériaux, UMR 5627 CNRS, Université Claude Bernard Lyon I, Bât 305 RdC, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne - France

## Introduction

Packaging industries require new biodegradable food-compatible films with low O₂ permeability and controlled H₂O flux. Biopolymers such as starch are chosen as raw materials because of their low cost, renewability, and local origin. The morphology and properties of these polymers can be affected by the humidity rate and it is important to know how moisture affects their gas permeability. In this study, wheat starch has been acetylated to a degree of substitution of 2.7 (1) and dissolved into chloroform with triacetin added as a plasticizer (28.5 % by weight of membrane). Clear and bright films were obtained by the tape-casting technique. Permeability measurements with water vapour were made and in addition, O₂ and CO₂ transport properties were studied for different relative humidity (R.H.) conditions in order to determine if gas selectivity changes with the hydration state of the film at 20 °C.

## Water permeability

The specificity of this experiment is the acquisition of H₂O flux as a function of a large water pressure domain (figure 1).

<figure><img src="image_4.png" /><figcaption>Figure 1 : Influence of the initial conditions on the water flux</figcaption></figure>

Two initial film hydration conditions (1 and 2 in table 1) have been chosen in order to study the influence of plastification by water on water transport properties. These conditions are as follows : the upstream water pressure (P1) is equal to 12.5 and 18.4 mm Hg for the initial conditions 1 and 2. The downstream pressure (P2) is always equal to 0 at initial time.

As shown in Figure 1, for part of the water transfer, the flux decreases in proportion to the pressure gradient but the slopes differ. In the first condition, the membrane was submitted to an average relative humidity varying from 30 to 40 %, and for the second, one of between 60 and 80 %.

For these two hydration states, the results show a measurable modification of the transport properties (figure 1) : the flux is 2.5 times higher for hydration condition 2 and the permeability coefficients (table 1) are in a good agreement with literature values obtained for acetylated amylose (2). The diffusion coefficients reported in table 1 show no significant plastification effect on this material (factor 1.6).
<table><caption>Table 1: Water permeability and diffusion coefficients as a function of the initial conditions (P1 = upstream pressure / P2 = downstream pressure)</caption><thead><tr><th>Initial conditions<br>(mmHg)</th><th>Permeability coefficients (Barrers)<br>from 20 to 50% of the total transfer</th><th>Diffusion coefficients<br>from 0 to 50% of the total transfer<br>(10<sup>-10</sup> cm<sup>2</sup>.s<sup>-1</sup>)</th></tr></thead><tbody><tr><td>Cond 1: P1 = 12.5 / P2 = 0</td><td>9 900</td><td>59</td></tr><tr><td>Cond 2: P1 = 18.4 / P2 = 0</td><td>24 600</td><td>95</td></tr></tbody></table>

## Gas permeability at varying hydration rates :

Two gases are involved in the "breathing" of packaged aliments: O₂ and CO₂. In this study, CO₂/O₂ selectivity is studied as a function of relative humidity. The permeability coefficients (Pe) and diffusion coefficients (D) are presented in table 2. Comparison of the results obtained at 0 and 60% R.H., shows that the selectivity is only slightly affected by this R.H. increase. CO₂/O₂ selectivity decreases from 1.8 to 1.3.

<table><caption>Table 2: Permeability coefficients at varying hydration rates</caption><thead><tr><th></th><th>0 % R.H.</th><th>60 % R.H.</th><th>95 % R.H.</th></tr></thead><tbody><tr><td>Pe (Barrers)</td><td>27</td><td>36</td><td>42</td></tr><tr><td>CO₂<br>D (10<sup>-10</sup>cm²/s)</td><td>345</td><td>-</td><td>-</td></tr><tr><td>Pe (Barrers)</td><td>15</td><td>25</td><td>-</td></tr><tr><td>O₂<br>D (10<sup>-10</sup>cm²/s)</td><td>321</td><td>-</td><td>-</td></tr></tbody></table>

The diffusion coefficients are not given at 60 and 95 % (±5%) R.H because of the low definition of the non steady state region of the permeation curve. No values are reported for oxygen permeation at high humidity rates because the flux tended towards very low values. It appears that water sorbed in the membrane is close to liquid state (3, 4), disturbing significantly the O₂ permeation and therefore the selectivity.

## Conclusion

Permeation measurements have been made for acetylated starch (DS 2.7) plasticized with triacetin. The measured CO₂/O₂ selectivities are low and seem to be only slightly dependent on film hydration until 60% R.H. and are significantly enhanced for 95-100% R.H. Therefore, further experiments are necessary to study how gas transport properties and selectivity are influenced by the triacetin content and the degree of substitution of the acetylation treatment.

## Acknowledgements :

We thank Europol'Agro and Région Champagne Ardenne for financial support.

## References

1) B. Laignel, C. Bliard, J. M. Nuzillard, G. Massiot, *Carbohydr. Res.*, **298** (1997) 251

2) A.T. Gros, R. O. Feuge, *J. Am. Oil. Chem. Soc.* **39** (1962) 19

3) C. Joly, R. Gauthier, M. Escoubes, *J. Appli. Polym. Sci.*, **61** (1996) 57

4) C. Fringant, J. Desbrières, M. Milas, M. Rinaudo, C. Joly, M. Escoubes, *Int. J. Bio. Macrom.*, **18** (1996) 281