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. 2016 Jul 14;8(7):259.
doi: 10.3390/polym8070259.

Oxidized Xanthan Gum and Chitosan as Natural Adhesives for Cork

Diana Paiva  1 , Carolina Gonçalves  2 , Isabel Vale  3 , Margarida M S M Bastos  4 , Fernão D Magalhães  5
Affiliations

Oxidized Xanthan Gum and Chitosan as Natural Adhesives for Cork

Diana Paiva et al. Polymers (Basel). .

Abstract

Natural cork stopper manufacturing produces a significant amount of cork waste, which is granulated and combined with synthetic glues for use in a wide range of applications. There is a high demand for using biosourced polymers in these composite materials. In this study, xanthan gum (XG) and chitosan (CS) were investigated as possible natural binders for cork. Xanthan gum was oxidized at two different aldehyde contents as a strategy to improve its water resistance. This modification was studied in detail by ¹H and 13C nuclear magnetic resonance (NMR), and the degree of oxidation was determined by the hydroxylamine hydrochloride titration method. The performance of the adhesives was studied by tensile tests and total soluble matter (TSM) determinations. Xanthan gum showed no water resistance, contrary to oxidized xanthan gum and chitosan. It is hypothesized that the good performance of oxidized xanthan gum is due to the reaction of aldehyde groups-formed in the oxidation process-with hydroxyl groups on the cork surface during the high temperature drying. Combining oxidized xanthan gum with chitosan did not yield significant improvements.

Keywords: chitosan; cork; natural adhesive; oxidized polysaccharide; oxidized xanthan gum.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Hydroxylamine hydrochloride titration method for oxidized xanthan gum (XGox) sample with a measured aldehyde content of 61%.
Figure 2
Figure 2
Chemical structure of native xanthan gum molecule: A,B: β-d-glucose ; C: O-acetylated α-d-mannose; D: β-d-glucuronic acid; E: pyruvated β-d-mannose unit (adapted from [36]).
Figure 3
Figure 3
1H NMR spectra for xanthan gum (XG) and oxidized xanthan gum (XGox) obtained at 55 °C.
Figure 4
Figure 4
Proposed structures for the terminal mannose unit of the side chain at different stages of oxidation: (E) non-oxidized pyruvated mannose; (E1) oxidized pyruvated mannose –C-2–C-3 cleavage; (E2) loss of pyruvic acid by β-elimination and formation of a double bond between C-4–C-5; (E3) non-oxidized mannose; (E4) oxidized mannose –C-2–C-4 and loss of C-3 as formaldehyde.
Figure 5
Figure 5
Tensile strength and water resistance of cork joints glued with xanthan gum, oxidized xanthan gum, and chitosan adhesives for different concentrations. Error bars represent standard deviations for a minimum of five measurements.
Figure 6
Figure 6
Tensile strength and water resistance of cork joints glued with xanthan gum–chitosan and oxidized xanthan gum–chitosan glues (6% concentration). Error bars represent standard deviations for a minimum of five measurements.
See this image and copyright information in PMC

References

    1. Graça J., Santos S. Suberin: A biopolyester of plants’ skin. Macromol. Biosci. 2007;7:128–135. doi: 10.1002/mabi.200600218. - DOI - PubMed
    1. Gibson L.J., Easterling K.E., Ashby M.F. The structure and mechanics of cork. Proc. R. Soc. A. 1981;377:99–117. doi: 10.1098/rspa.1981.0117. - DOI
    1. Pereira H. The rationale behind cork properties: A review of structure and chemistry. BioResource. 2015;10:6207–6229. doi: 10.15376/biores.10.3.Pereira. - DOI
    1. Cordeiro N., Belgacem M.N., Gandini A., Pascoal Neto C. Urethanes and polyurethanes from suberin 2: Synthesis and characterization. Ind. Crop. Prod. 1999;10:1–10. doi: 10.1016/S0926-6690(98)00029-6. - DOI
    1. Silva S.P., Sabino M.A., Fernandes E.M., Correlo V.M., Boesel L.F., Reis R.L. Cork: Properties, capabilities and applications. Int. Mater. Rev. 2005;50:345–365. doi: 10.1179/174328005X41168. - DOI

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