On the unique morphology and elastic properties of multi-jet electrospun cashew gum-based fiber mats

Authors: GRUMI, MATTIA - Institute Of Agrochemistry And Food Technology; PRIETO, CRISTINA - Institute Of Agrochemistry And Food Technology; FURTADO, ROSELAYNE - Embrapa Tropical Agroindustry; Cheng, Huai; Biswas, Atanu; LIMBO, SARA - Military Health System; CABEDO, LUIS - 32892; LAGARON, JOSE - Institute Of Agrochemistry And Food Technology

Submitted to: Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2024
Publication Date: 5/10/2024
Citation: Grumi, M., Prieto, C., Furtado, R.F., Cheng, H.N., Biswas, A., Limbo, S., Cabedo, L., Lagaron, J.M. 2024. On the unique morphology and elastic properties of multi-jet electrospun cashew gum-based fiber mats. Polymers. 16. Article 1355. https://doi.org/10.3390/polym16101355.
DOI: https://doi.org/10.3390/polym16101355

Interpretive Summary: Cashew gum, obtained from the exudates of the cashew tree, is a byproduct of the cashew nut production. It is currently under-utilized, and only a small amount is used in food and pharmaceutical applications. It is desirable to find new and high-value uses for cashew gum. In this work, we investigated the possibility of using electrospinning to produce microfibers from cashew gum. It turned out that cashew gum by itself did not produce good fibers, but the addition of polyethylene oxide and glycerol under suitable electrospinning conditions produced satisfactory microfibers with unique morphology and properties. The findings in this work opened up the opportunities to use this cashew gum-based material for food packaging, textiles, and other applications.

Technical Abstract: This work focuses on the study of the electrospinnability of cashew gum and the comprehensive characterization of the obtained fiber mats. Cashew gum (CG) is an agro-based, inexpensive, non-toxic polysaccharide obtained from Anacardium occidentale trees. The electrospinnability of aqueous solutions of cashew gum alone or in combination with a higher molecular weight supporting polymer, PEO, was explored. Samples were characterized in terms of morphology, physicochemical properties, thermal stability, and mechanical properties. According to the obtained results, it was not possible to obtain pure fibers of cashew gum alone; nevertheless, the minimum amount of PEO required to generate the molecular entanglements necessary to obtain the desired fibers was determined. Straight and smooth fibers with some defects were obtained with a ratio CG:PEO of 85:15 and an average diameter of 0.94 ± 0.23 'm. However, a purification step of the aqueous solution of cashew gum and the use of glycerol as plasticizer helped to obtain straight and smooth fibers free of defects with an average size of 3.06 ' 1.03 'm. As regards the thermal properties, blending of cashew gum and PEO resulted in the reduction of the crystallinity of the PEO phase and in the reduction of the thermal stability of the fibers in comparison to the pure components, potentially enabling multiple applications where processing temperatures remain below 120 ºC. Surprisingly, when the selected formulation was electrospun from multiple emitters over a drum collector rotating at the very low rotation speed of 100 rpm, more thickly aligned fiber bundles, never reported before, were obtained in the rotational direction with interconnecting fibers between the bundles in the transverse direction. Such natural fiber orientation has been hypothesized to be achieved by strong self-association of the fine jets of the CG-based formulation during flying, intercepting the well-known whipping motion typically associated with the electrospinning process. Additionally, an unexpectedly high elongation at break was found that was unique for the resultant oriented fiber mats. These results make this bio-polysaccharide-based formulation a promising material for future investigations in several fields such as food packaging and textiles.