{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:16:45Z","timestamp":1785421005006,"version":"3.56.0"},"reference-count":52,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T00:00:00Z","timestamp":1782950400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006749","name":"Burapha University","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100006749","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/01ff74m36","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100017170","name":"Thailand Science Research and Innovation","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100017170","id-type":"DOI","asserted-by":"crossref"}]},{"id":[{"id":"https:\/\/ror.org\/000025p04","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100017170","name":"National Science Research and Innovation Fund","doi-asserted-by":"publisher","award":["1.18\/2568"],"award-info":[{"award-number":["1.18\/2568"]}],"id":[{"id":"10.13039\/501100017170","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Coconut husk lignin was fractionated using ethanol to obtain nanolignin fractions with distinct physicochemical properties. Among the fractions, CNF1 exhibited the most favorable combination of particle size, thermal stability, and antibacterial activity and was selected for further modification. Microwave-assisted esterification of CNF1 with maleic anhydride was performed under various reaction temperatures and lignin-to-maleic anhydride ratios. Structural modification was confirmed by ATR-FTIR spectroscopy through the appearance of ester carbonyl groups and an increase in the degree of esterification, which reached its highest value at 180 \u00b0C and a lignin-to-maleic anhydride ratio of 1:10. TEM analysis revealed that maleation increased nanoparticle size, whereas WAXD demonstrated that both native and modified lignins retained predominantly amorphous structures. Antioxidant activity decreased with increasing esterification due to the reduction of phenolic hydroxyl groups. Thermal analysis showed that esterification altered the degradation behavior of lignin, while thermo-oxidative stability measurements indicated improved oxidation resistance for highly esterified samples. The 10MA180 sample exhibited the highest thermo-oxidative stability, with a T2,O2 value of 12.55 min, a residual mass of 84.90%, and the lowest weight loss after 60 min oxidation. These findings demonstrate that microwave-assisted maleation effectively tailors the structure and functional properties of nanolignin for sustainable bio-based material applications.<\/jats:p>","DOI":"10.3390\/ijms27135950","type":"journal-article","created":{"date-parts":[[2026,7,2]],"date-time":"2026-07-02T14:51:25Z","timestamp":1783003885000},"page":"5950","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Microwave-Assisted Maleation of Coconut Husk Nanolignin: Structure\u2013Property Relationships Governed by Degree of Esterification"],"prefix":"10.3390","volume":"27","author":[{"given":"Wissawat","family":"Sakulsaknimitr","sequence":"first","affiliation":[{"name":"Department of Fundamental Science and Physical Education, Faculty of Science, Kasetsart University, Sriracha Campus, Chonburi 20230, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-9448-5236","authenticated-orcid":false,"given":"Pornpen","family":"Atorngitjawat","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,2]]},"reference":[{"key":"ref_1","unstructured":"Intergovernmental Panel on Climate Change (IPCC) (2023). Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC."},{"key":"ref_2","unstructured":"United Nations Environment Programme (UNEP) (2024). Emissions Gap Report 2024, United Nations Environment Programme."},{"key":"ref_3","first-page":"125434","article-title":"A critical review of organic waste valorization for sustainable bioeconomy","volume":"337","author":"Awasthi","year":"2021","journal-title":"Bioresour. Technol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2301","DOI":"10.1016\/j.biortech.2006.08.008","article-title":"Lignin\u2014From natural adsorbent to activated carbon: A review","volume":"98","author":"Suhas","year":"2007","journal-title":"Bioresour. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1021\/sc500087z","article-title":"Progress in green polymer composites from lignin for multifunctional applications: A review","volume":"2","author":"Thakur","year":"2014","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_6","first-page":"573","article-title":"Preparation of lignin nanoparticles and their applications in composite materials: A review","volume":"145","author":"Huang","year":"2019","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1007\/s10570-010-9436-4","article-title":"Isolation, preparation, and characterization of nanofibers from oil palm empty-fruit-bunch","volume":"17","author":"Fahma","year":"2010","journal-title":"Cellulose"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1146\/annurev.arplant.54.031902.134938","article-title":"Lignin biosynthesis","volume":"54","author":"Boerjan","year":"2003","journal-title":"Annu. Rev. Plant Biol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3552","DOI":"10.1021\/cr900354u","article-title":"The catalytic valorization of lignin for the production of renewable chemicals","volume":"110","author":"Zakzeski","year":"2010","journal-title":"Chem. Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3392","DOI":"10.1021\/acssuschemeng.7b03583","article-title":"Lignin functionalized with succinic anhydride as building block for biobased thermosetting polyester coatings","volume":"6","author":"Scarica","year":"2018","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1266","DOI":"10.1016\/j.progpolymsci.2013.11.004","article-title":"Chemical modification of lignins: Towards biobased polymers","volume":"39","author":"Laurichesse","year":"2014","journal-title":"Prog. Polym. Sci."},{"key":"ref_12","first-page":"14215","article-title":"Maleated Technical Lignin Thermosets and Biocomposites Designed for Degradation","volume":"12","author":"Gioia","year":"2024","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"8342","DOI":"10.3390\/app13148342","article-title":"Incorporation of lignin in bio-based resins for potential fiber-reinforced polymer composite applications","volume":"13","author":"Machado","year":"2023","journal-title":"Appl. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1016\/j.ijbiomac.2014.09.044","article-title":"Recent advances in green hydrogels from lignin: A review","volume":"72","author":"Thakur","year":"2015","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"6250","DOI":"10.1002\/anie.200400655","article-title":"Controlled microwave heating in modern organic synthesis","volume":"43","author":"Kappe","year":"2004","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1358","DOI":"10.1039\/b9nr00377k","article-title":"Microwave chemistry for inorganic nanomaterials synthesis","volume":"2","author":"Bilecka","year":"2010","journal-title":"Nanoscale"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1515\/hfsg.1991.45.s1.21","article-title":"Classification of lignins from different botanical origins by FTIR spectroscopy","volume":"45","author":"Faix","year":"1991","journal-title":"Holzforschung"},{"key":"ref_18","first-page":"24657","article-title":"Lignin-Based Nanomaterials: Interfacial Adhesion and Advanced Sustainable Applications","volume":"17","year":"2025","journal-title":"Nanoscale"},{"key":"ref_19","first-page":"2533","article-title":"Lignin-Based Functional Materials for Sustainable Technologies","volume":"24","author":"Naghdi","year":"2022","journal-title":"Green Chem."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ortega-Sanhueza, I., Girard, V., Ziegler-Devin, I., Chapuis, H., Brosse, N., Valenzuela, F., Banerjee, A., Fuentealba, C., Cabrera-Barjas, G., and Torres, C. (2024). Preparation and Characterization of Lignin Nanoparticles from Different Plant Sources. Polymers, 16.","DOI":"10.3390\/polym16111610"},{"key":"ref_21","first-page":"102777","article-title":"Synthesis of lignin nanoparticles by nanoprecipitation followed by ultrasonication for nanocomposite application","volume":"35","author":"Worku","year":"2023","journal-title":"J. King Saud Univ. Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1006\/abio.1996.0292","article-title":"The ferric reducing ability of plasma as a measure of antioxidant power: The FRAP assay","volume":"239","author":"Benzie","year":"1996","journal-title":"Anal. Biochem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1016\/j.biortech.2004.02.024","article-title":"Characterization of the radical scavenging activity of lignins\u2014Natural antioxidants","volume":"95","author":"Dizhbite","year":"2004","journal-title":"Bioresour. Technol."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Qazi, S.S., Li, S., Li, C., Wang, Z., and Li, Y. (2017). Antioxidant Activity of Lignins Derived from Fluidized-Bed Fast Pyrolysis. Molecules, 22.","DOI":"10.3390\/molecules22030372"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1016\/j.indcrop.2004.04.022","article-title":"Characterisation of structure-dependent functional properties of lignin with infrared spectroscopy","volume":"20","author":"Boeriu","year":"2004","journal-title":"Ind. Crops Prod."},{"key":"ref_26","first-page":"379","article-title":"Physico-chemical and structural characterization of lignins from agricultural residues","volume":"58","author":"Sun","year":"1997","journal-title":"Polym. Degrad. Stab."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1969","DOI":"10.1002\/(SICI)1097-4628(19990321)71:12<1969::AID-APP6>3.0.CO;2-D","article-title":"A study of chemical structure of soft and hardwood and wood polymers by FTIR spectroscopy","volume":"71","author":"Pandey","year":"1999","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1655","DOI":"10.1016\/j.biortech.2006.05.042","article-title":"Physico-chemical characterization of lignins from different sources for use in phenol\u2013formaldehyde resin synthesis","volume":"98","author":"Tejado","year":"2007","journal-title":"Bioresour. Technol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4963","DOI":"10.1039\/C4GC01242A","article-title":"Lignin nanoparticles: Preparation, characterization and applications","volume":"16","author":"Qian","year":"2014","journal-title":"Green Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"6468","DOI":"10.1021\/acs.langmuir.6b01088","article-title":"Synthesis and Characterization of Biodegradable Lignin Nanoparticles with Tunable Surface Properties","volume":"32","author":"Richter","year":"2016","journal-title":"Langmuir"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5488","DOI":"10.15376\/biores.9.3.5488-5500","article-title":"Chemical Modification of Kraft Lignin: Effect on Chemical and Thermal Properties","volume":"9","author":"Chen","year":"2014","journal-title":"BioResources"},{"key":"ref_32","first-page":"485","article-title":"Fractionation of Industrial Lignin and Its Applications","volume":"22","author":"Li","year":"2020","journal-title":"Green Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1175","DOI":"10.1039\/C5GC02616D","article-title":"Towards Lignin-Based Functional Materials in a Sustainable World","volume":"18","author":"Kai","year":"2016","journal-title":"Green Chem."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Beisl, S., Miltner, A., and Friedl, A. (2017). Lignin from micro- to nanosize: Applications. Int. J. Mol. Sci., 18.","DOI":"10.3390\/ijms18112367"},{"key":"ref_35","first-page":"1101","article-title":"Valorization of Lignin Nanoparticles in Sustainable Materials","volume":"14","author":"Yang","year":"2021","journal-title":"Materials"},{"key":"ref_36","first-page":"9212","article-title":"Lignin Nanoparticles: Recent Advances and Emerging Applications","volume":"37","author":"Richter","year":"2021","journal-title":"Langmuir"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1451","DOI":"10.3390\/ph6121451","article-title":"Effect of Essential Oils on Pathogenic Bacteria","volume":"6","author":"Nazzaro","year":"2013","journal-title":"Pharmaceuticals"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Breijyeh, Z., Jubeh, B., and Karaman, R. (2020). Resistance of Gram-Negative Bacteria to Current Antibacterial Agents and Approaches to Resolve It. Molecules, 25.","DOI":"10.3390\/molecules25061340"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1781","DOI":"10.1016\/j.fuel.2006.12.013","article-title":"Characteristics of hemicellulose, cellulose and lignin pyrolysis","volume":"86","author":"Yang","year":"2007","journal-title":"Fuel"},{"key":"ref_40","first-page":"353","article-title":"Thermal degradation of lignin\u2014A review","volume":"44","author":"Brebu","year":"2010","journal-title":"Cellul. Chem. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1021\/ef0200323","article-title":"Pyrolysis of lignins: Experimental and kinetics studies","volume":"16","author":"Ferdous","year":"2002","journal-title":"Energy Fuels"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/j.biortech.2018.09.072","article-title":"From lignin to valuable products\u2014Strategies, challenges, and prospects","volume":"271","author":"Wang","year":"2019","journal-title":"Bioresour. Technol."},{"key":"ref_43","first-page":"395","article-title":"Reaction of lignin with maleic anhydride and its characterization","volume":"51","author":"Matsushita","year":"2005","journal-title":"J. Wood Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1895","DOI":"10.1021\/bm0500345","article-title":"Lignin esters for use in unsaturated thermosets: Lignin modification and solubility modeling","volume":"6","author":"Thielemans","year":"2005","journal-title":"Biomacromolecules"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.indcrop.2005.10.002","article-title":"Structural characterization of technical lignins for the production of adhesives","volume":"24","year":"2006","journal-title":"Ind. Crops Prod."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1039\/C4GC01333F","article-title":"Lignin: A Nature-Inspired Sun Blocker for Broad-Spectrum Sunscreens","volume":"17","author":"Qian","year":"2015","journal-title":"Green Chem."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4655","DOI":"10.1021\/jf970539p","article-title":"Derivatization followed by reductive cleavage (DFRC): A new method for lignin analysis","volume":"45","author":"Lu","year":"1997","journal-title":"J. Agric. Food Chem."},{"key":"ref_48","unstructured":"Hatakeyama, H., and Hatakeyama, T. (2010). Thermal Properties of Green Polymers and Biocomposites, Springer."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/0141-3910(90)90094-N","article-title":"Thermooxidative degradation of polymers in the solid state: Experimental kinetics of polyethylene oxidation","volume":"27","author":"Gugumus","year":"1990","journal-title":"Polym. Degrad. Stab."},{"key":"ref_50","unstructured":"Zweifel, H., Maier, R.D., and Schiller, M. (2009). Plastics Additives Handbook, Hanser Publishers. [6th ed.]."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1023\/A:1021148205366","article-title":"Polymer weathering: Photo-oxidation","volume":"10","author":"Feldman","year":"2002","journal-title":"J. Polym. Environ."},{"key":"ref_52","first-page":"5487","article-title":"Structural characterization of pine kraft lignin","volume":"7","author":"Hu","year":"2012","journal-title":"BioResources"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/13\/5950\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,4]],"date-time":"2026-07-04T04:57:48Z","timestamp":1783141068000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/27\/13\/5950"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,2]]},"references-count":52,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["ijms27135950"],"URL":"https:\/\/doi.org\/10.3390\/ijms27135950","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,2]]}}}