Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지
DOI QR코드

DOI QR Code

Synchrotron X-Ray Diffraction Studies on Crystalline Domains in Urea-Formaldehyde Resins at Low Molar Ratio

  • WIBOWO, Eko Setio (Department of Wood and Paper Science, Kyungpook National University) ;
  • PARK, Byung-Dae (Department of Wood and Paper Science, Kyungpook National University) ;
  • CAUSIN, Valerio (Dipartimento di Scienze Chimiche, Universita di Padova) ;
  • HAHN, Dongyup (School of Food Science and Biotechnology, Kyungpook National University)
  • Received : 2022.07.04
  • Accepted : 2022.09.08
  • Published : 2022.09.25
Download PDF
⟨ Previous Next ⟩

Abstract

The crystalline domain of thermosetting urea-formaldehyde (UF) resins at low formaldehyde-to-urea (F/U) molar ratios (≤ 1.0) is known to be responsible for their poor performance as wood adhesives. Crystallization has been observed in 1.0 F/U UF resins during the addition reaction stage and at the end of the synthesis process (neat UF resins). The crystallinity and X-ray diffraction (XRD) spectra of the uncured neat UF resins, on the other hand, differed significantly from those of the cured neat UF resins, raising the possibility that their crystal structures were also different. This study demonstrates for the first time that the crystalline domains in 1.0 F/U UF resins generated from uncured and cured samples are identical. Despite having a lower crystallinity value, the synchrotron XRD patterns of purified neat UF resins were equivalent to the XRD patterns of cured neat UF resins. Transmission electron microscope images of the cured UF resins showed that the crystals were lamellar structures. This finding suggests that the crystal at low molar ratio UF resins are isotropic polycrystals with random orientation.

Keywords

Acknowledgement

This work was supported by the National Research Foundation (NRF) of Korea funded by the Korean Government (MSIT) (Grant No. 2020R1A2C1005042).

References

  1. Baruchel, J., Di Michiel, M., Lafford, T., Lhuissier, P., Meyssonnier, J., Nguyen-Thi, H., Philip, A., Pernot, P., Salvo, L., Scheel, M. 2013. Synchrotron X-ray imaging for crystal growth studies. Comptes Rendus Physique 14(2-3): 208-220. https://doi.org/10.1016/j.crhy.2012.10.010
  2. Despres, A., Pizzi, A. 2006. Colloidal aggregation of aminoplastic polycondensation resins: Urea-formaldehyde versus melamine-formaldehyde and melamine-urea-formaldehyde resins. Journal of Applied Polymer Science 100(2): 1406-1412. https://doi.org/10.1002/app.23230
  3. Drnovsek, N., Kocen, R., Gantar, A., Drobnic-Kosorok, M., Leonardi, A., Krizaj, I., Recnik, A., Novak, S. 2016. Size of silk fibroin β-sheet domains affected by Ca2+. Journal of Materials Chemistry B 4(40): 6597-6608. https://doi.org/10.1039/C6TB01101B
  4. Ferg, E.E., Pizzi, A., Levendis, D.C. 1993. 13C NMR analysis method for urea-formaldehyde resin strength and formaldehyde emission. Journal of Applied Polymer Science 50(5): 907-915. https://doi.org/10.1002/app.1993.070500519
  5. Han, H., Lee, S., Yang, S., Choi, C., Kang, S. 2019. Evaluation of formaldehyde emission from wood-based panels using accelerated collection method. Journal of the Korean Wood Science and Technology 47(2): 129-144. https://doi.org/10.5658/WOOD.2019.47.2.129
  6. Hong, M.K., Lubis, M.A.R., Park, B.D. 2017. Effect of panel density and resin content on properties of medium density fiberboard. Journal of the Korean Wood Science and Technology 45(4): 444-455. https://doi.org/10.5658/WOOD.2017.45.4.444
  7. Jeong, B., Park, B.D. 2019. Performance of urea-for-maldehyde resins synthesized at two different low molar ratios with different numbers of urea addition. Journal of the Korean Wood Science and Technology 47(2): 221-228. https://doi.org/10.5658/WOOD.2019.47.2.221
  8. Jeong, B., Park, B.D., Causin, V. 2020. Effects of storage time on molecular weights and properties of melamine-urea-formaldehyde resins. Journal of the Korean Wood Science and Technology 48(3): 291-302. https://doi.org/10.5658/WOOD.2020.48.3.291
  9. Keith Dunker, A., John, W.E., Rammon, R., Farmer, B., Johns, S.J. 1986. Slightly bizarre protein chemistry: Urea-formaldehyde resin from a biochemical perspective. The Journal of Adhesion 19(2): 153-176. https://doi.org/10.1080/00218468608071219
  10. Kim, J.K., Lee, C., Lim, S.W., Adhikari, A., Andring, J.T., McKenna, R., Ghim, C.M., Kim, C.U. 2020. Elucidating the role of metal ions in carbonic anhydrase catalysis. Nature Communications 11(1): 4557. https://doi.org/10.1038/s41467-020-18425-5
  11. Kim, M., Park, B.D. 2021a. A method of measuring wood failure percentage of wood specimens bonded with melamine-urea-formaldehyde resins using image analysis. Journal of the Korean Wood Science and Technology 49(3): 274-282. https://doi.org/10.5658/WOOD.2021.49.3.274
  12. Kim, M., Park, B.D. 2021b. Effects of synthesis method, melamine content and GPC parameter on the molecular weight of melamine-urea-formaldehyde resins. Journal of the Korean Wood Science and Technology 49(1): 1-13. https://doi.org/10.5658/WOOD.2021.49.1.1
  13. Kuei, B., Aplan, M.P., Litofsky, J.H., Gomez, E.D. 2020. New opportunities in transmission electron microscopy of polymers. Materials Science and Engineering: R: Reports 139: 100516. https://doi.org/10.1016/j.mser.2019.100516
  14. Levendis, D., Pizzi, A., Ferg, E. 1992. The correlation of strength and formaldehyde emission with the crystalline/amorphous structure of UF resins. Holzforschung 46(3): 263-269. https://doi.org/10.1515/hfsg.1992.46.3.263
  15. Li, J., Zhang, Y. 2021. Morphology and crystallinity of urea-formaldehyde resin adhesives with different molar ratios. Polymers 13(5): 673. https://doi.org/10.3390/polym13050673
  16. Libera, M.R., Egerton, R.F. 2010. Advances in the transmission electron microscopy of polymers. Polymer Reviews 50(3): 321-339. https://doi.org/10.1080/15583724.2010.493256
  17. Lin, F., Liu, Y., Yu, X., Cheng, L., Singer, A., Shpyrko, O.G., Xin, H.L., Tamura, N., Tian, C., Weng, T.C., Yang, X.Q., Meng, Y.S., Nordlund, D., Yang, W., Doeff, M.M. 2017. Synchrotron X-ray analytical techniques for studying materials electrochemistry in rechargeable batteries. Chemical Reviews 117(21) 13123-13186. https://doi.org/10.1021/acs.chemrev.7b00007
  18. Liu, M., Thirumalai, R.V.K.G., Wu, Y., Wan, H. 2017. Characterization of the crystalline regions of cured urea formaldehyde resin. RSC Advances 7(78): 49536-49541. https://doi.org/10.1039/C7RA08082D
  19. Lubis, M.A.R., Jeong, B., Park, B.D., Lee, S.M., Kang, E.C. 2019a. Effect of synthesis method and melamine content of melamine-urea-formaldehyde resins on bond-line features in plywood. Journal of the Korean Wood Science and Technology 47(5): 579-586. https://doi.org/10.5658/WOOD.2019.47.5.579
  20. Lubis, M.A.R., Park, B.D. 2020. Influence of initial molar ratios on the performance of low molar ratio urea-formaldehyde resin adhesives. Journal of the Korean Wood Science and Technology 48(2): 136-153. https://doi.org/10.5658/WOOD.2020.48.2.136
  21. Lubis, M.A.R., Park, B.D., Lee, S.M. 2019b. Performance of hybrid adhesives of blocked-pMDI/melamine-urea-formaldehyde resins for the surface lamination on plywood. Journal of the Korean Wood Science and Technology 47(2): 200-209. https://doi.org/10.5658/WOOD.2019.47.2.200
  22. Myers, G.E. 1984. How mole ratio of UF resin affects formaldehyde emission and other properties: A literature critique. Forest Products Journal 34(5): 35-41.
  23. Nuryawan, A., Singh, A.P., Zanetti, M., Park, B.D., Causin, V. 2017. Insights into the development of crystallinity in liquid urea-formaldehyde resins. International Journal of Adhesion and Adhesives 72: 62-69. https://doi.org/10.1016/j.ijadhadh.2016.10.004
  24. Park, B.D., Causin, V. 2013. Crystallinity and domain size of cured urea-formaldehyde resin adhesives with different formaldehyde/urea mole ratios. European Polymer Journal 49(2): 532-537. https://doi.org/10.1016/j.eurpolymj.2012.10.029
  25. Park, B.D., Jeong, H.W. 2011. Hydrolytic stability and crystallinity of cured urea-formaldehyde resin adhesives with different formaldehyde/urea mole ratios. International Journal of Adhesion and Adhesives 31(6): 524-529. https://doi.org/10.1016/j.ijadhadh.2011.05.001
  26. Park, B.D., Jeong, H.W., Lee, S.M. 2011. Morphology and chemical elements detection of cured urea-for-maldehyde resins. Journal of Applied Polymer Science 120(3): 1475-1482. https://doi.org/10.1002/app.33247
  27. Park, S., Park, B.D. 2021. Crystallinity of low molar ratio urea-formaldehyde resins modified with cellulose nanomaterials. Journal of the Korean Wood Science and Technology 49(2): 169-180. https://doi.org/10.5658/WOOD.2021.49.2.169
  28. Pizzi, A., Lipschitz, L., Valenzuela, J. 1994. Theory and practice of the preparation of low formaldehyde emission UF adhesives. Holzforschung 48(3): 254-261. https://doi.org/10.1515/hfsg.1994.48.3.254
  29. Pratt, T.J., Johns, W.E., Rammon, R.M., Plagemann, W.L. 1985. A novel concept on the structure of cured urea-formaldehyde resin. The Journal of Adhesion 17(4): 275-295. https://doi.org/10.1080/00218468508081165
  30. Schuett, T., Geitner, R., Zechel, S., Schubert, U.S. 2021. Dialysis diffusion kinetics in polymer purification. Macromolecules 54(20): 9410-9417. https://doi.org/10.1021/acs.macromol.1c01241
  31. Sedigh Rahimabadi, P., Khodaei, M., Koswattage, K.R. 2020. Review on applications of synchrotron-based X-ray techniques in materials characterization. X-Ray Spectrometry 49(3): 348-373. https://doi.org/10.1002/xrs.3141
  32. Singh, A.P., Causin, V., Nuryawan, A., Park, B.D. 2014. Morphological, chemical and crystalline features of urea-formaldehyde resin cured in contact with wood. European Polymer Journal 56: 185-193. https://doi.org/10.1016/j.eurpolymj.2014.04.014
  33. Singh, A.P., Nuryawan, A., Park, B.D., Lee, K.H. 2015. Urea-formaldehyde resin penetration into Pinus radiata tracheid walls assessed by TEM-EDXS. Holzforschung 69(3): 303-306. https://doi.org/10.1515/hf-2014-0103
  34. Steinhof, O., Kibrik, E.J., Scherr, G., Hasse, H. 2014. Quantitative and qualitative 1H, 13C, and 15N NMR spectroscopic investigation of the urea-formaldehyde resin synthesis. Magnetic Resonance in Chemistry 52(4): 138-162. https://doi.org/10.1002/mrc.4044
  35. Stuligross, J., Koutsky, J.A. 1985. A morphological study of urea-formaldehyde resins. The Journal of Adhe-sion 18(4): 281-299. https://doi.org/10.1080/00218468508080464
  36. Tosaka, M., Danev, R., Nagayama, K. 2005. Application of phase contrast transmission microscopic methods to polymer materials. Macromolecules 38(19): 7884-7886. https://doi.org/10.1021/ma0512197
  37. Wang, H., Cao, M., Li, T., Yang, L., Duan, Z., Zhou, X., Du, G. 2018. Characterization of the low molar ratio urea-formaldehyde resin with 13C NMR and ESI-MS: Negative effects of the post-added urea on the urea-formaldehyde polymers. Polymers 10(6): 602. https://doi.org/10.3390/polym10060602
  38. Wibowo, E.S., Lubis, M.A.R., Park, B.D. 2021. Simultaneous improvement of formaldehyde emission and adhesion of medium-density fiberboard bonded with low-molar ratio urea-formaldehyde resins modified with nanoclay. Journal of the Korean Wood Science and Technology 49(5): 453-461. https://doi.org/10.5658/WOOD.2021.49.5.453
  39. Wibowo, E.S., Lubis, M.A.R., Park, B.D., Kim, J.S., Causin, V. 2020a. Converting crystalline thermosetting urea-formaldehyde resins to amorphous polymer using modified nanoclay. Journal of Industrial and Engineering Chemistry 87: 78-89. https://doi.org/10.1016/j.jiec.2020.03.014
  40. Wibowo, E.S., Park, B.D. 2020. Determination of crystallinity of thermosetting urea-formaldehyde resins using deconvolution method. Macromolecular Research 28(6): 615-624. https://doi.org/10.1007/s13233-020-8076-2
  41. Wibowo, E.S., Park, B.D. 2021. Crystalline lamellar structure of thermosetting urea-formaldehyde resins at a low molar ratio. Macromolecules 54(5): 2366-2375. https://doi.org/10.1021/acs.macromol.1c00073
  42. Wibowo, E.S., Park, B.D. 2022. Two-dimensional nuclear magnetic resonance analysis of hydrogen-bond for-mation in thermosetting crystalline urea-formaldehyde resins at a low molar ratio. ACS Applied Polymer Materials 4(2): 1084-1094. https://doi.org/10.1021/acsapm.1c01521
  43. Wibowo, E.S., Park, B.D., Causin, V. 2020b. Hydrogenbond-induced crystallization in low-molar-ratio urea -formaldehyde resins during synthesis. Industrial & Engineering Chemistry Research 59(29): 13095-13104. https://doi.org/10.1021/acs.iecr.0c02268
  44. Wibowo, E.S., Park, B.D., Causin, V. 2022. Recent advances in urea-formaldehyde resins: Converting crystalline thermosetting polymers back to amorphous ones. Polymer Reviews 62(4): 722-756. https://doi.org/10.1080/15583724.2021.2014520
  45. Widjonarko, N.E. 2016. Introduction to advanced X-ray diffraction techniques for polymeric thin films. Coatings 6(4): 54. https://doi.org/10.3390/coatings6040054