Kısmen Pirolize Edilmiş ve Delignifiye Edilmiş Lignin ile Modifiye Edilmiş Üre-Formaldehit Reçine Sistemleri: Bir İnceleme

Abstract

Üre-formaldehit (UF) reçineleri, odun kökenli ürünlerin üretiminde yaygın olarak kullanılan tipik yapıştırıcılardır. Bununla birlikte, formaldehit emisyonu yayan bu tür fosil yakıt bazlı reçinelerin kullanımı, çevre ve insan sağlığı açısından ciddi riskler oluşturmaktadır. Doğal yapıştırıcı ve su itici özelliklere sahip biyo-bazlı lignin polimeri, UF reçinelerinde ikame katkı maddesi olarak değerlendirilebilmektedir. Lignin reçine yapısına eklendiğinde, metilen bağlarının bulunduğu bölgelerde yeni bağların oluşmasıyla C-N bağlarının sayısında azalma meydana gelmektedir. Ancak, zayıf bağlanma kapasitesi ve amorf yapısı nedeniyle ham lignin doğrudan UF reçinelerine eklenememekte; ön işlemden geçirilmesi gerekmektedir. Bu doğrultuda, çalışmada inert atmosfer altında düşük sıcaklık bölgesinde ligninin kısmi pirolizi önerilmektedir. Söz konusu reaksiyon, kısmi C–O bağlarının parçalanması yoluyla daha uzun zincirli bir yapı oluşturarak ligninin kimyasal yapısını değiştirmektedir. Bu yöntemin formaldehit emisyonlarını azaltması beklenmekle birlikte, ortaya çıkan zincir yapısının su iticiliği artıracağı ve ligninin nem içeriğini düşüreceği öngörülmektedir. Literatürde yer alan araştırmalar, lignin katkılarının reçine viskozitesi, serbest formaldehit içeriği, yapışma performansı ve panel özellikleri üzerinde kayda değer etkiler gösterdiğini ortaya koymaktadır.

Keywords

• Lignin
• UF Reçine
• Tutkal
• Kısmi Piroliz
• Depolimerizasyon

Supporting Institution

The Scientific and Technological Research Council of Türkiye (TÜBİTAK), Istanbul Gedik University

Project Number

5230122

Ethical Statement

Bu Makale TÜBİTAK Üniversite-Sanayi İş birliği Destek Programı tarafından İstanbul Gedik Üniversitesi 5230122 numaralı Proje ile desteklenmiştir

Urea-Formaldehyde Resin Systems Modified with Partially Pyrolyzed and Delignified Lignin: A Review

Abstract

Urea-formaldehyde UF resins are typical adhesives employed in the production of wood-derived products. Application of such fossil fuel-based resins that emit formaldehyde emissions endangers the environmental and human health conditions profoundly. Bio-based lignin polymer can be utilized as a replacement additive in UF resins because it has inherent adhesive and water repellent nature. When lignin is added into the structure of the resin, the C-N bonds are reduced through the creation of new bonds within regions containing methylene bonds. Raw lignin cannot be directly added to UF resins; it must undergo pretreatment due to its poor binding capacity and amorphous nature. Therefore, partial pyrolysis of lignin in the low temperature zone under inert atmosphere was suggested in this study. This reaction creates a longer chain structure by partial C-O bond fragmentation; thus lignin is altered. This method is likely to reduce the formaldehyde emissions, but the same chain structure will increase the water repellency and reduce the moisture content of lignin. Literature research reveals that lignin additives have great effects on resin viscosity, free formaldehyde content, adhesion quality and panel performance.

Keywords

• lignin
• UF Resin
• Depolimerization
• Partial Pyrolysis
• Adhesives

Supporting Institution

TÜBİTAK, İstanbul Gedik Üniversitesi

Project Number

5230122

Ethical Statement

This article has been supported by the TÜBİTAK University-Industry Collaboration Support Program through Project No. 5230122 at Istanbul Gedik University.

References

1. [1] M. Hassegawa, J. Van Brusselen, M. Cramm, and P. J. Verkerk, “Wood-Based Products in the Circular Bioeconomy: Status and Opportunities towards Environmental Sustainability,” Land (Basel), vol. 11, no. 12, p. 2131, Dec. 2022, doi: 10.3390/LAND11122131/S1.
2. [2] Á. Galán-Martín, V. Tulus, I. Díaz, C. Pozo, J. Pérez-Ramírez, and G. Guillén-Gosálbez, “Sustainability footprints of a renewable carbon transition for the petrochemical sector within planetary boundaries,” One Earth, vol. 4, no. 4, pp. 565–583, Apr. 2021, doi: 10.1016/J.ONEEAR.2021.04.001/ATTACHMENT/D5F8717E-7F87-4C2E-B364-370B57DB7741/MMC2.PDF.
3. [3] C. Yu, Y. Chen, R. Li, J. Jiang, and X. Wang, “A Narrative Review: Modification of Bio-Based Wood Adhesive for Performance Improvement,” Coatings 2024, Vol. 14, Page 1153, vol. 14, no. 9, p. 1153, Sep. 2024, doi: 10.3390/COATINGS14091153.
4. [4] E. A. R. Zuiderveen et al., “The potential of emerging bio-based products to reduce environmental impacts,” Nat Commun, vol. 14, no. 1, pp. 1–7, Dec. 2023, doi:10.1038/S41467-023-43797-9;SUBJMETA=106,172,2739,4081,682,694,704;KWRD=CLIMATE-CHANGE+IMPACTS,CLIMATE-CHANGE+MITIGATION,ENVIRONMENTAL+IMPACT.
5. [5] S. Ghahri, L. Yang, G. Du, and B. D. Park, “Transition from Formaldehyde-Based Wood Adhesives to Bio-Based Alternatives.,” Bioresources, vol. 20, no. 2, pp. 2476–2479, 2025, doi: 10.15376/BIORES.20.2.2476-2479.
6. [6] G. Yang, Z. Gong, X. Luo, L. Chen, and L. Shuai, “Bonding wood with uncondensed lignins as adhesives,” Nature, vol. 621, no. 7979, pp. 511–515, Sep. 2023, doi: 10.1038/S41586-023-06507-5;SUBJMETA=224,303,455,638,639,685;KWRD=MECHANICAL+PROPERTIES,SUSTAINABILITY.
7. [7] W. Tian et al., “Development of High Strength, High Water Resistant, Low-Formaldehyde Emission Urea-Formaldehyde Adhesive and Its Effect on the Properties of Wood Composites,” J Appl Polym Sci, vol. 142, no. 10, p. e56548, Mar. 2025, doi: 10.1002/APP.56548;WGROUP:STRING:PUBLICATION.
8. [8] K. Saito, Y. Hirabayashi, and S. Yamanaka, “Reduction of formaldehyde emission from urea-formaldehyde resin with a small quantity of graphene oxide,” RSC Adv, vol. 11, no. 52, pp. 32830–32836, Oct. 2021, doi: 10.1039/D1RA06717F.

9. [9] M. A. Aristri et al., “Recent Developments in Lignin- and Tannin-Based Non-Isocyanate Polyurethane Resins for Wood Adhesives—A Review,” Applied Sciences 2021, Vol. 11, Page 4242, vol. 11, no. 9, p. 4242, May 2021, doi: 10.3390/APP11094242.
10. [10] P. Antov, V. Savov, and N. Neykov, “WOOD RESEARCH 65 (1): 2020 xx-xx SUSTAINABLE BIO-BASED ADHESIVES FOR ECO-FRIENDLY WOOD COMPOSITES. A REVIEW”.
11. [11] H. Younesi-Kordkheili and A. Pizzi, “A Comparison among Lignin Modification Methods on the Properties of Lignin–Phenol–Formaldehyde Resin as Wood Adhesive,” Polymers 2021, Vol. 13, Page 3502, vol. 13, no. 20, p. 3502, Oct. 2021, doi: 10.3390/POLYM13203502.
12. [12] W. Peng, C. Dong, J. An, G. Zhang, P. Wang, and Y. Xie, “A Novel Formaldehyde-Free Wood Adhesive Synthesized by Straw Soda Lignin and Polyethyleneimine.,” Bioresources, vol. 18, no. 2, pp. 3123–3143, May 2023, doi: 10.15376/BIORES.18.2.3123-3143.
13. [13] N. C. Carpita and M. C. McCann, “Redesigning plant cell walls for the biomass-based bioeconomy,” Journal of Biological Chemistry, vol. 295, no. 44, pp. 15144–15157, Oct. 2020, doi: 10.1074/JBC.REV120.014561.
14. [14] Y. Li et al., “An ideal lignin facilitates full biomass utilization,” Sci Adv, vol. 4, no. 9, Sep. 2018, doi: 10.1126/SCIADV.AAU2968/SUPPL_FILE/AAU2968_SM.PDF.
15. [15] A. Limayem and S. C. Ricke, “Lignocellulosic biomass for bioethanol production: Current perspectives, potential issues and future prospects,” Prog Energy Combust Sci, vol. 38, no. 4, pp. 449–467, Aug. 2012, doi: 10.1016/J.PECS.2012.03.002.
16. [16] A. P. Ingle, S. Saxena, M. P. Moharil, J. D. Rivaldi, L. Ramos, and A. K. Chandel, “Production of biomaterials and biochemicals from lignocellulosic biomass through sustainable approaches: current scenario and future perspectives,” Biotechnology for Sustainable Materials 2025 2:1, vol. 2, no. 1, pp. 1–30, Mar. 2025, doi: 10.1186/S44316-025-00025-2.
17. [17] A. Saxena, F. Parveen, A. Hussain, M. Khubaib, and M. Ashfaque, “Exploring the multifaceted landscape of lignocellulosic biomass-derived nanocellulose and nanolignin: synthesis and applications,” Polymer Bulletin 2025 82:13, vol. 82, no. 13, pp. 7525–7563, Jun. 2025, doi: 10.1007/S00289-025-05855-8.
18. [18] S. Darmawan, N. J. Wistara, G. Pari, A. Maddu, and W. Syafii, “Characterization of Lignocellulosic Biomass as Raw Material for the Production of Porous Carbon-based Materials.,” Bioresources, vol. 11, no. 2, pp. 3561–3574, May 2016, doi: 10.15376/BIORES.11.2.3561-3574.
19. [19] A. Woźniak, K. Kuligowski, L. Świerczek, and A. Cenian, “Review of Lignocellulosic Biomass Pretreatment Using Physical, Thermal and Chemical Methods for Higher Yields in Bioethanol Production,” Sustainability 2025, Vol. 17, Page 287, vol. 17, no. 1, p. 287, Jan. 2025, doi: 10.3390/SU17010287.
20. [20] J. C. Del Río, J. Rencoret, A. Gutiérrez, T. Elder, H. Kim, and J. Ralph, “Lignin Monomers from beyond the Canonical Monolignol Biosynthetic Pathway: Another Brick in the Wall,” ACS Sustain Chem Eng, vol. 8, no. 13, pp. 4997–5012, Apr. 2020, doi: 10.1021/ACSSUSCHEMENG.0C01109/ASSET/IMAGES/LARGE/SC0C01109_0006.JPEG.
21. [21] X. Kang, A. Kirui, M. C. Dickwella Widanage, F. Mentink-Vigier, D. J. Cosgrove, and T. Wang, “Lignin-polysaccharide interactions in plant secondary cell walls revealed by solid-state NMR,” Nature Communications 2019 10:1, vol. 10, no. 1, pp. 1–9, Jan. 2019, doi: 10.1038/s41467-018-08252-0.
22. [22] A. J. Ragauskas et al., “Lignin Valorization: Improving Lignin Processing in the Biorefinery,” Science (1979), vol. 344, no. 6185, May 2014, doi: 10.1126/SCIENCE.1246843.
23. [23] V. B. Agbor, N. Cicek, R. Sparling, A. Berlin, and D. B. Levin, “Biomass pretreatment: Fundamentals toward application,” Biotechnol Adv, vol. 29, no. 6, pp. 675–685, Nov. 2011, doi: 10.1016/J.BIOTECHADV.2011.05.005.
24. [24] H. Wang, Y. Pu, A. Ragauskas, and B. Yang, “From lignin to valuable products–strategies, challenges, and prospects,” Bioresour Technol, vol. 271, pp. 449–461, Jan. 2019, doi: 10.1016/J.BIORTECH.2018.09.072.
25. [25] L. Dessbesell, M. Paleologou, M. Leitch, R. Pulkki, and C. (Charles) Xu, “Global lignin supply overview and kraft lignin potential as an alternative for petroleum-based polymers,” Renewable and Sustainable Energy Reviews, vol. 123, p. 109768, May 2020, doi: 10.1016/J.RSER.2020.109768.
26. [26] D. S. Bajwa, G. Pourhashem, A. H. Ullah, and S. G. Bajwa, “A concise review of current lignin production, applications, products and their environmental impact,” Ind Crops Prod, vol. 139, p. 111526, Nov. 2019, doi: 10.1016/J.INDCROP.2019.111526.
27. [27] M. Al-Naji, F. Brandi, M. Drieß, and F. Rosowski, “From Lignin to Chemicals: An Expedition from Classical to Modern Catalytic Valorization Technologies,” Chemie Ingenieur Technik, vol. 94, no. 11, pp. 1611–1627, Nov. 2022, doi: 10.1002/CITE.202200079.
28. [28] S. Laurichesse and L. Avérous, “Chemical modification of lignins: Towards biobased polymers,” Prog Polym Sci, vol. 39, no. 7, pp. 1266–1290, Jul. 2014, doi: 10.1016/J.PROGPOLYMSCI.2013.11.004.
29. [29] F. Vásquez-Garay, I. Carrillo-Varela, C. Vidal, P. Reyes-Contreras, M. Faccini, and R. T. Mendonça, “A Review on the Lignin Biopolymer and Its Integration in the Elaboration of Sustainable Materials,” Sustainability 2021, Vol. 13, Page 2697, vol. 13, no. 5, p. 2697, Mar. 2021, doi: 10.3390/SU13052697.
30. [30] A. de S. M. de Freitas et al., “Improvements in thermal and mechanical properties of composites based on thermoplastic starch and Kraft Lignin,” Int J Biol Macromol, vol. 184, pp. 863–873, Aug. 2021, doi: 10.1016/J.IJBIOMAC.2021.06.153.
31. [31] A. Ait Benhamou et al., “Advances in Lignin Chemistry, Bonding Performance, and Formaldehyde Emission Reduction in Lignin-Based Urea-Formaldehyde Adhesives: A Review,” ChemSusChem, vol. 18, no. 16, p. e202500491, Aug. 2025, doi: 10.1002/CSSC.202500491.
32. [32] O. Gordobil, R. Delucis, I. Egüés, and J. Labidi, “Kraft lignin as filler in PLA to improve ductility and thermal properties,” Ind Crops Prod, vol. 72, pp. 46–53, Oct. 2015, doi: 10.1016/J.INDCROP.2015.01.055.
33. [33] Z. Sun, B. Fridrich, A. De Santi, S. Elangovan, and K. Barta, “Bright Side of Lignin Depolymerization: Toward New Platform Chemicals,” Chem Rev, vol. 118, no. 2, pp. 614–678, Jan. 2018, doi: 10.1021/ACS.CHEMREV.7B00588.
34. [34] R. Roy, M. S. Rahman, T. A. Amit, and B. Jadhav, “Recent Advances in Lignin Depolymerization Techniques: A Comparative Overview of Traditional and Greener Approaches,” Biomass 2022, Vol. 2, Pages 130-154, vol. 2, no. 3, pp. 130–154, Jul. 2022, doi: 10.3390/BIOMASS2030009.
35. [35] C. Chio, M. Sain, and W. Qin, “Lignin utilization: A review of lignin depolymerization from various aspects,” Renewable and Sustainable Energy Reviews, vol. 107, pp. 232–249, Jun. 2019, doi: 10.1016/J.RSER.2019.03.008.
36. [36] N. Zhou, W. P. D. W. Thilakarathna, Q. S. He, and H. P. V. Rupasinghe, “A Review: Depolymerization of Lignin to Generate High-Value Bio-Products: Opportunities, Challenges, and Prospects,” Front Energy Res, vol. 9, p. 758744, Jan. 2022, doi: 10.3389/FENRG.2021.758744/FULL.
37. [37] X. Lu and X. Gu, “A review on lignin pyrolysis: pyrolytic behavior, mechanism, and relevant upgrading for improving process efficiency,” Biotechnology for Biofuels and Bioproducts, vol. 15, no. 1, pp. 1–43, Dec. 2022, doi: 10.1186/S13068-022-02203-0/TABLES/6.
38. [38] D. ; Martins-Vieira et al., “Review on Biomass Pyrolysis with a Focus on Bio-Oil Upgrading Techniques,” Analytica 2023, Vol. 4, Pages 182-205, vol. 4, no. 2, pp. 182–205, May 2023, doi: 10.3390/ANALYTICA4020015.
39. [39] A. Singh-Morgan, A. Puente-Urbina, and J. A. van Bokhoven, “Technology Overview of Fast Pyrolysis of Lignin: Current State and Potential for Scale-Up,” ChemSusChem, vol. 15, no. 14, p. e202200343, Jul. 2022, doi: 10.1002/CSSC.202200343.
40. [40] R. K. Mishra, D. Jaya Prasanna Kumar, R. Sankannavar, P. Binnal, and K. Mohanty, “Hydro-deoxygenation of pyrolytic oil derived from pyrolysis of lignocellulosic biomass: A review,” Fuel, vol. 360, p. 130473, Mar. 2024, doi: 10.1016/J.FUEL.2023.130473.
41. [41] J. Li et al., “Comprehensive mechanism of initial stage for lignin pyrolysis,” Combust Flame, vol. 215, pp. 1–9, May 2020, doi: 10.1016/J.COMBUSTFLAME.2020.01.016.
42. [42] J. M. Yuan et al., “Valorization of lignin into phenolic compounds via fast pyrolysis: Impact of lignin structure,” Fuel, vol. 319, p. 123758, Jul. 2022, doi: 10.1016/J.FUEL.2022.123758.
43. [43] C. R. Frihart, “Potential for Biobased Adhesives in Wood Bonding,” Proceedings of the 59th International Convention of Society of Wood Science and Technology, pp. 84–91, 2016, Accessed: Sep. 11, 2025. [Online]. Available: https://research.fs.usda.gov/treesearch/50956.
44. [44] A. Rindler, O. Vay, C. Hansmann, and J. Konnerth, “Adhesive-related warping of thin wooden bi-layers,” Wood Sci Technol, vol. 53, no. 5, pp. 1015–1033, Sep. 2019, doi: 10.1007/S00226-019-01124-W/FIGURES/7.
45. [45] I. Calvez, R. Garcia, A. Koubaa, V. Landry, and A. Cloutier, “Recent Advances in Bio-Based Adhesives and Formaldehyde-Free Technologies for Wood-Based Panel Manufacturing,” Current Forestry Reports, vol. 10, no. 5, pp. 386–400, Oct. 2024, doi: 10.1007/S40725-024-00227-3/TABLES/2.
46. [46] A. Akinterinwa, A. Ismaila, and B. Aliyu, “Concise Chemistry of Urea Formaldehyde Resins and Formaldehyde Emission”, doi: 10.33552/ICBC.2020.01.000507.
47. [47] B. Jeong and B. D. Park, “Effect of molecular weight of urea–formaldehyde resins on their cure kinetics, interphase, penetration into wood, and adhesion in bonding wood,” Wood Sci Technol, vol. 53, no. 3, pp. 665–685, May 2019, doi: 10.1007/S00226-019-01092-1/FIGURES/12.
48. [48] S. Sultana, M. Mannan, M. Jaynal Abedin, Z. Islam, H. Parvin Nur, and P. Rani Samaddar, “PHYSICO-MECHANICAL AND THERMAL PROPERTIES OF THERMOPLASTIC POLY(VINYL ALCOHOL) MODIFIED THERMOSETTING UREA FORMALDEHYDE RESIN,” ADVANCES IN MATERIALS SCIENCE, vol. 21, no. 4, 2021, doi: 10.2478/adms-2021-0024.
49. [49] X. Wang, H. Zhao, B. Zhang, X. Wen, S. Huang, and W. Gan, “The Removal of Formaldehyde from Urea Formaldehyde Adhesive by Sodium Borohydride Treatment and Its Application in Plywood,” Polymers 2024, Vol. 16, Page 969, vol. 16, no. 7, p. 969, Apr. 2024, doi: 10.3390/POLYM16070969.
50. [50] D. Gonçalves, J. M. Bordado, A. C. Marques, and R. G. Dos Santos, “Non-Formaldehyde, Bio-Based Adhesives for Use in Wood-Based Panel Manufacturing Industry—A Review,” Polymers 2021, Vol. 13, Page 4086, vol. 13, no. 23, p. 4086, Nov. 2021, doi: 10.3390/POLYM13234086.
51. [51] D. Cavallo et al., “New formaldehyde-free adhesives for wood manufacturing: In vitro evaluation of potential toxicity of fine dust collected during wood sawing using a new experimental model to simulate occupational inhalation exposure,” Toxicology, vol. 466, p. 153085, Jan. 2022, doi: 10.1016/J.TOX.2021.153085.
52. [52] L. Kristak et al., “Recent progress in ultra-low formaldehyde emitting adhesive systems and formaldehyde scavengers in wood-based panels: a review,” Wood Mater Sci Eng, vol. 18, no. 2, pp. 763–782, Mar. 2023, doi: 10.1080/17480272.2022.2056080.
53. [53] A. Kumar, P. B. Patil, and D. V. Pinjari, “Eco-friendly adhesives for wood panels: advances in lignin, tannin, protein, and rubber-based solutions,” J Adhes Sci Technol, vol. 39, no. 17, pp. 2628–2669, 2025, doi: 10.1080/01694243.2025.2514151.
54. [54] T. Tešić, M. Rančič, D. B. Bogdanović, and I. G. Grmuša, “The influence of tannin on the improvement of adhesive properties of urea-formaldehyde resin,” Zastita Materijala, vol. 66, no. 1, pp. 119–125, Mar. 2025, doi: 10.62638/ZASMAT1140.
55. [55] M. Ristić et al., “Hydrolytic and thermal stability of urea-formaldehyde resins based on tannin and betaine bio-fillers,” Journal of Vinyl and Additive Technology, vol. 29, no. 6, pp. 1082–1092, Nov. 2023, doi: 10.1002/VNL.22024.
56. [56] P. Antov, V. Savov, L. Krišt’ák, R. Réh, and G. I. Mantanis, “Eco-Friendly, High-Density Fiberboards Bonded with Urea-Formaldehyde and Ammonium Lignosulfonate,” Polymers 2021, Vol. 13, Page 220, vol. 13, no. 2, p. 220, Jan. 2021, doi: 10.3390/POLYM13020220.
57. [57] E. S. Wibowo and B. D. Park, “Direct measurement of surface adhesion between thin films of nanocellulose and urea–formaldehyde resin adhesives,” Cellulose, vol. 28, no. 13, pp. 8459–8481, Sep. 2021, doi: 10.1007/S10570-021-04088-Y/TABLES/6.
58. [58] H. Li et al., “Synthesis and Characterization of an Environmentally Friendly Phenol–Formaldehyde Resin Modified with Waste Plant Protein,” Polymers 2023, Vol. 15, Page 2975, vol. 15, no. 13, p. 2975, Jul. 2023, doi: 10.3390/POLYM15132975.
59. [59] A. Arias et al., “Recent developments in bio-based adhesives from renewable natural resources,” J Clean Prod, vol. 314, p. 127892, Sep. 2021, doi: 10.1016/J.JCLEPRO.2021.127892.
60. [60] P. Bekhta et al., “Properties of Eco-Friendly Particleboards Bonded with Lignosulfonate-Urea-Formaldehyde Adhesives and pMDI as a Crosslinker,” Materials 2021, Vol. 14, Page 4875, vol. 14, no. 17, p. 4875, Aug. 2021, doi: 10.3390/MA14174875.
61. [61] A. Dorieh et al., “Advancing Sustainable Building Materials: Reducing Formaldehyde Emissions in Medium Density Fiber Boards with Lignin Nanoparticles,” Adv Sustain Syst, vol. 8, no. 9, p. 2400102, Sep. 2024, doi: 10.1002/ADSU.202400102.
62. [62] G. B. Paul, M. C. Timar, O. Zeleniuc, A. Lunguleasa, and C. Coșereanu, “Mechanical Properties and Formaldehyde Release of Particleboard Made with Lignin-Based Adhesives,” Applied Sciences 2021, Vol. 11, Page 8720, vol. 11, no. 18, p. 8720, Sep. 2021, doi: 10.3390/APP11188720.
63. [63] M. Němec, L. Prokůpek, V. Obst, T. Pipíška, P. Král, and Š. Hýsek, “Novel kraft-lignin-based adhesives for the production of particleboards,” Compos Struct, vol. 344, p. 118344, Sep. 2024, doi: 10.1016/J.COMPSTRUCT.2024.118344.
64. [64] S. Gao et al., “Unexpected role of amphiphilic lignosulfonate to improve the storage stability of urea formaldehyde resin and its application as adhesives,” Int J Biol Macromol, vol. 161, pp. 755–762, Oct. 2020, doi: 10.1016/J.IJBIOMAC.2020.06.135.
65. [65] Y. Ma et al., “Biodegradable Films Prepared from Pulp Lignocellulose Adhesives of Urea Formaldehyde Resin Modified by Biosulfonate,” Polymers 2022, Vol. 14, Page 2863, vol. 14, no. 14, p. 2863, Jul. 2022, doi: 10.3390/POLYM14142863.
66. [66] O. A. Adegoke, O. Y. Ogunsanwo, and K. O. Olaoye, “Modification of Urea Formaldehyde Resin with Pyrolytic Oil on Particleboard,” Journal of Forest and Environmental Science, vol. 36, no. 3, pp. 219–224, 2020, doi: 10.7747/JFES.2020.36.3.219.