Impact of the lignin type and source on the characteristics of physical lignin hydrogels
| Autor: | Patricia Gullón, Amaia Morales, Jalel Labidi |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
Vinyl alcohol
Renewable Energy Sustainability and the Environment Chemistry Swelling capacity technology industry and agriculture food and beverages lignin poly (vinyl alcohol) macromolecular substances Biorefinery complex mixtures Industrial and Manufacturing Engineering almond shells chemistry.chemical_compound Adsorption walnut shells Chemical engineering Self-healing hydrogels Lignin General Materials Science physical hydrogels Glass transition Waste Management and Disposal Chemical composition |
| Zdroj: | Addi. Archivo Digital para la Docencia y la Investigación instname |
| Popis: | [EN] Multiple natural polymers have been investigated for the synthesis of hydrogels to the present date, but lignin has demonstrated to be a promising one for this purpose for the multiple advantages it offers. Lignin can be isolated from lignocellulosic material such as nut shells, which are usually undervalued wastes, and would be a great step forward on circular economy. Thus, in the present work, lignin was extracted from almond and walnut shells following a single-step (delignification) and double-step (autohydrolysis and delignification) biorefinery scheme. After the chemical composition and structures of these lignins were determined, hydrogels were synthesized combining them with poly (vinyl alcohol) by the means of freeze-thawing cycles so as to study the influence of the different lignins on their final properties. Additionally, the last thawing cycle of the synthesis process was lengthened in order to confirm previous assumptions about its effect on the characteristics of the synthesized materials. The obtained results showed significant variation between the 8 lignin samples, especially in their purity, molecular weights and total phenolic contents. The variation on the lignins leaded to several hydrogel morphologies, which directly affected their properties, primarily their swelling capacity, glass transition temperatures and compression strengths. It was also demonstrated the great effect that the duration of the last thawing had on the morphology and, hence, on the characteristics of the obtained materials. The synthesized samples were successfully employed as dye adsorbents and the evaluation of their antifungal activity showed positive results in some of the samples, which could be applied for food packaging. The authors would like to acknowledge the financial support of the Department of Education of the Basque Government (IT1008-16). A. Morales would like to thank the University of the Basque Country (Training of Researcher Staff, PIF17/207). P. Gull ' on would like to acknowledge the Grants for the recruitment of technical support staff (PTA2019-017850-I) under the State Plan for Scientific and Technical Research and Innovation 2017-2020. The authors thank SGIker (UPV/EHU/ERDF, EU) for their technical and human support. |
| Databáze: | OpenAIRE |
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