Abstract
Wood, a natural anisotropic material, behaves differently in the radial (R) and tangential direction (T), which also gives rise to different penetration capacity of adhesive into wood tissues. The present study investigates the penetration behavior of adhesive in the interphase of three different wood laminates, namely R-R, T-R, and T-T combinations, and its effect on microstructure and micromechanical properties of the latewood bonding interphase using confocal laser scanning microscopy (CLSM) and nanoindentation (NI). The results showed that the average penetration depth (AP) of the radial surface (SR) was higher than that of the tangential surface (ST) and a significant improvement in the mechanics of cells compared with the control cell (C). the maximum reduced elastic modulus (E r ) and hardness (H) found at the fourth cell row were 21.7 GPa and 0.62 GPa for R-R laminate, respectively, which increased by 43% and 29% compared with C (15.1 GPa, 0.48 GPa), and the maximum E r and H found at the first cell row were 23.2 GPa and 0.65 GPa for T-T laminate, respectively, which increased by 52% and 44% compared with C (15.3 GPa, 0.45 GPa). The results provide an important platform for better understanding and predicting the properties of wood glue line and bonding interphase.
Funding source: National Natural Science Foundation of China
Award Identifier / Grant number: 31890772
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: This study was supported by the National Natural Science Foundation of China (Grant no. 31890772).
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Altgen, M., Awais, M., Altgen, D., Kluppel, A., Makela, M., and Rautkari, L. (2020). Distribution and curing reactions of melamine formaldehyde resin in cells of impregnation-modified wood. Sci. Rep. 10: 3366, https://doi.org/10.1038/s41598-020-60418-3.Search in Google Scholar
Bastani, A., Adamopoulos, S., and Militz, H. (2015). Effect of open assembly time and equilibrium moisture content on the penetration of polyurethane adhesive into thermally modified wood. J. Adhes. 93: 575–583, https://doi.org/10.1080/00218464.2015.1118621.Search in Google Scholar
Bockel, S., Harling, S., Grönquist, P., Niemz, P., Pichelin, F., Weiland, G., and Konnerth, J. (2020). Characterization of wood-adhesive bonds in wet conditions by means of nanoindentation and tensile shear strength. Eur. J. Wood Wood Prod. 78: 449–459, https://doi.org/10.1007/s00107-020-01520-1.Search in Google Scholar
Dill-Langer, G., Lütze, S., and Aicher, S. (2002). Microfracture in wood monitored by confocal laser scanning microscopy. Wood Sci. Technol. 36: 487–499, https://doi.org/10.1007/s00226-002-0151-7.Search in Google Scholar
Fengel, D. (1972). Structure and function of the membrane in softwood bordered pits. Holzforschung 26: 1–9, https://doi.org/10.1515/hfsg.1972.26.1.1.Search in Google Scholar
Frazier, C.E. and Ni, J.W. (1998). On the occurrence of network interpenetration in the wood-isocyanate adhesive interphase. Int. J. Adhesion Adhes. 18: 81–87, https://doi.org/10.1016/s0143-7496(97)00048-1.Search in Google Scholar
Furuno, T., Imamura, Y., and Kajita, H. (2004). The modification of wood by treatment with low molecular weight phenol-formaldehyde resin: a properties enhancement with neutralized phenolic-resin and resin penetration into wood cell walls. Wood Sci. Technol. 37: 349–361.10.1007/s00226-003-0176-6Search in Google Scholar
Gavrilović-Grmuša, I., Dunky, M., Miljković, J., and Djiporović-Momčilović, M. (2010a). Radial penetration of urea-formaldehyde adhesive resins into beech (Fagus moesiaca). J. Adhes. Sci. Technol. 24: 1753–1768.10.1163/016942410X507812Search in Google Scholar
Gavrilović-Grmuša, I., Miljković, J., and Ðiporović-Momčilović, M. (2010b). Influence of the degree of condensation on the radial penetration of urea-formaldehyde adhesives into Silver Fir (Abies alba, Mill.) wood tissue. J. Adhes. Sci. Technol. 24: 1437–1453.10.1163/016942410X501034Search in Google Scholar
Gavrilović-Grmuša, I., Dunky, M., Miljkovic, J., and Djiporovic-Momcilovic, M. (2012). Influence of the viscosity of UF resins on the radial and tangential penetration into poplar wood and on the shear strength of adhesive joints. Holzforschung 66: 849–856, https://doi.org/10.1515/hf-2011-0177.Search in Google Scholar
Gindl, W. (2001). SEM and UV-microscopic investigation of glue lines in Parallam® PSL. Holz als Roh- Werkst. 59: 211–214, https://doi.org/10.1007/s001070100194.Search in Google Scholar
Gindl, W., Sretenovic, A., Vincenti, A., and Müller, U. (2005). Direct measurement of strain distribution along a wood bond line. Part 2: effects of adhesive penetration on strain distribution. Holzforschung 59: 307–310, https://doi.org/10.1515/hf.2005.051.Search in Google Scholar
Gindl, W., Schoberl, T., and Keckes, J. (2006). Structure and properties of pulp fiber-reinforced composite with regenerated cellulose matrix. Appl. Phys. A 83: 19–22, https://doi.org/10.1007/s00339-005-3451-6.Search in Google Scholar
Groom, L., So, C.L., Elder, T., Pesacreta, T., and Rials, T. (2004). Proceedings of the seventh Pacific Rim Bio-Based Composites Symposium, October 31th-November 2nd, 2004: Effect of refining pressure and resin viscosity on resin flow, distribution and penetration of MDF fibers. Science & Technique Literature Press, Nanjing, China.Search in Google Scholar
He, G. and Riedl, B. (2004). Curing kinetics of phenol formaldehyde resin and wood-resin interactions in the presence of wood substrates. Wood Sci. Technol. 38: 69–81.10.1007/s00226-003-0221-5Search in Google Scholar
Herzele, S., Van Herwijnen, H.W.G., Griesser, T., Gindl-Altmutter, W., Rößler, C., and Konnerth, J. (2020). Differences in adhesion between 1C-PUR and MUF wood adhesives to (ligno)cellulosic surfaces revealed by nanoindentation. Int. J. Adhesion Adhes. 98: 102507, https://doi.org/10.1016/j.ijadhadh.2019.102507.Search in Google Scholar
Huang, Y.X., Lin, Q.Q., Yang, C., Bian, G.M., Zhang, Y.H., and Yu, W.J. (2020). Multi-scale characterization of bamboo bonding interfaces with phenol-formaldehyde resin of different molecular weight to study the bonding mechanism. J. R. Soc. Interface 17: 20190755, https://doi.org/10.1098/rsif.2019.0755.Search in Google Scholar PubMed PubMed Central
Jakes, J.E., Hunt, C.G., Yelle, D.J., Lorenz, L., Hirth, K., Gleber, S.C., Vogt, S., Grigsby, W., and Frihart, C.R. (2015). Synchrotron-based X-ray fluorescence microscopy in conjunction with nanoindentation to study molecular-scale interactions of phenol-formaldehyde in wood cell walls. ACS Appl. Mater. Interfaces 7: 6584–6589, https://doi.org/10.1021/am5087598.Search in Google Scholar PubMed
Jakes, J.E., Frihart, C.R., Hunt, C.G., Yelle, D.J., and Nayomi, Z.P. (2019). X-ray methods to observe and quantify adhesive penetration into wood. J. Mater. Sci. 54: 705–718, https://doi.org/10.1007/s10853-018-2783-5.Search in Google Scholar
Jeong, B. and Park, B.D. (2019). Effect of molecular weight of urea–formaldehyde resins on their cure kinetics, interphase, penetration into wood, and adhesion in bonding wood. Wood Sci. Technol. 53: 665–685, https://doi.org/10.1007/s00226-019-01092-1.Search in Google Scholar
Jiang, Z.H., Yu, Y., Qin, D.C., Wang, G., Zhang, B., and Fu, Y.J. (2006). Pilot investigation of the mechanical properties of wood flooring paint films by in situ imaging nanoindentation. Holzforschung 60: 698–701, https://doi.org/10.1515/hf.2006.118.Search in Google Scholar
Johnson, S.E. and Kamke, F.A. (1992). Quantitative analysis of gross adhesive penetration in wood using fluorescence microscopy. J. Adhes. 40: 47–61, https://doi.org/10.1080/00218469208030470.Search in Google Scholar
Kamke, F.A. and Lee, J.N. (2007). Adhesive penetration in wood - a review. Wood Fiber Sci. 39: 205–220.Search in Google Scholar
Konnerth, J. and Gindl, W. (2006). Mechanical characterisation of wood-adhesive interphase cell walls by nanoindentation. Holzforschung 60: 429–433, https://doi.org/10.1515/hf.2006.067.Search in Google Scholar
Konnerth, J., Gierlinger, N., Keckes, J., and Gindl, W. (2009). Actual versus apparent within cell wall variability of nanoindentation results from wood cell walls related to cellulose microfibril angle. J. Mater. Sci. 44: 4399–4406, https://doi.org/10.1007/s10853-009-3665-7.Search in Google Scholar PubMed PubMed Central
Konnerth, J., Eiser, M., Jäger, A., Bader, T.K., Hofstetter, K., Follrich, J., Ters, T., Hansmann, C., and Wimmer, R. (2010). Macro and micro-mechanical properties of red oak wood (Quercus rubra L.) treated with hemicellulases. Holzforschung 64: 447–453, https://doi.org/10.1515/hf.2010.056.Search in Google Scholar
Lippke, B.B., Wilson, J., Garcia, J.P., Bowyer, J., and Meil, J. (2004). CORRIM: life-cycle environmental performance of renewable building materials. For. Prod. J. 54: 8–19.Search in Google Scholar
Liu, M.H., Lyu, S.Y., Peng, L.M., Cai, L.P., Huang, Z.H., and Lyu, J.X. (2021). Improvement of toughness and mechanical properties of furfurylated wood by biosourced epoxidized soybean oil. ACS Sustain. Chem. Eng. 9: 8142–8155, https://doi.org/10.1021/acssuschemeng.1c01358.Search in Google Scholar
Marra, A.A. (1992). Technology of wood bonding: principles in practice. Springer, New York.Search in Google Scholar
Modzel, G., Kamke, F.A., and De Carlo, F. (2010). Comparative analysis of a wood: adhesive bondline. Wood Sci. Technol. 45: 147–158, https://doi.org/10.1007/s00226-010-0304-z.Search in Google Scholar
Obersriebnig, M., Konnerth, J., and Gindl-Altmutter, W. (2013). Evaluating fundamental position-dependent differences in wood cell wall adhesion using nanoindentation. Int. J. Adhesion Adhes. 40: 129–134, https://doi.org/10.1016/j.ijadhadh.2012.08.011.Search in Google Scholar PubMed PubMed Central
Oliver, C.D., Nassar, N.T., Lippke, B.R., and Mccarter, J.B. (2014). Carbon, fossil fuel, and biodiversity mitigation with wood and forests. J. Sustain. For. 33: 248–275, https://doi.org/10.1080/10549811.2013.839386.Search in Google Scholar
Oliver, W.C. and Pharr, G.M. (1992). An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7: 1564–1583, https://doi.org/10.1557/jmr.1992.1564.Search in Google Scholar
Paris, J.L. and Kamke, F.A. (2015). Quantitative wood–adhesive penetration with X-ray computed tomography. Int. J. Adhesion Adhes. 61: 71–80, https://doi.org/10.1016/j.ijadhadh.2015.05.006.Search in Google Scholar
Pizzi, A., Mtsweni, B., and Parsons, W. (1994). Wood-induced catalytic activation of PF adhesives autopolymerization vs. PF/wood covalent bonding. J. Appl. Polym. Sci. 52: 1847–1856, https://doi.org/10.1002/app.1994.070521302.Search in Google Scholar
Pizzi, A. (2015). Synthetic adhesives for wood panels: chemistry and technology. In: Mittal, K.L. (Ed.), Progress in adhesion and adhesives. John Wiley & Sons, New York, pp. 85–123.10.1002/9781119162346.ch4Search in Google Scholar
Qin, L.Z., Lin, L.Y., Fu, F., and Fan, M.Z. (2017). Microstructure and quantitative micromechanical analysis of wood cell-emulsion polymer isocyanate and urea-formaldehyde interphases. Microsc. Microanal. 23: 687–695, https://doi.org/10.1017/s1431927617000216.Search in Google Scholar
Rao, F., Ji, Y.H., Huang, Y.X., Li, N., Zhang, Y.H., Chen, Y.H., and Yu, W.J. (2021). Influence of resin molecular weight on bonding interface, water resistance, and mechanical properties of bamboo scrimber composite. Construct. Build. Mater. 292: 123458, https://doi.org/10.1016/j.conbuildmat.2021.123458.Search in Google Scholar
Resnik, J., Sernek, M., and Kamke, F.A. (1997). High-frequency hating of wood with moisture content gradient. Wood Fiber Sci. 29: 264–271.Search in Google Scholar
Serrano-Ruiz, J.C., West, R.M., and Dumesic, J.A. (2010). Catalytic conversion of renewable biomass resources to fuels and chemicals. Annu. Rev. Chem. Biomol. Eng. 1: 79–100, https://doi.org/10.1146/annurev-chembioeng-073009-100935.Search in Google Scholar PubMed
Stoeckel, F., Konnerth, J., and Gindl-Altmutter, W. (2013). Mechanical properties of adhesives for bonding wood — a review. Int. J. Adhesion Adhes. 45: 32–41, https://doi.org/10.1016/j.ijadhadh.2013.03.013.Search in Google Scholar
Wang, W.Q. and Yan, N. (2005). Characterizing liquid resin penetration in wood using a mercury intrusion porosimeter. Wood Fiber Sci. 37: 505–513.Search in Google Scholar
Wang, X.Z., Deng, Y.H., Li, Y.J., Kjoller, K., Roy, A., and Wang, S.Q. (2016). In situ identification of the molecular-scale interactions of phenol-formaldehyde resin and wood cell walls using infrared nanospectroscopy. RSC Adv. 6: 76318–76324, https://doi.org/10.1039/c6ra13159j.Search in Google Scholar
Wang, X.Z., Zhao, L.G., Deng, Y.H., Li, Y.J., and Wang, S.Q. (2018). Effect of the penetration of isocyanates (pMDI) on the nanomechanics of wood cell wall evaluated by AFM-IR and nanoindentation (NI). Holzforschung 72: 301–309, https://doi.org/10.1515/hf-2017-0123.Search in Google Scholar
Wang, X.Z., Chen, X.Z., Xie, X.Q., Yuan, Z.R., Cai, S.X., and Li, Y.J. (2019). Effect of phenol formaldehyde resin penetration on the quasi-static and dynamic mechanics of wood cell walls using nanoindentation. Nanomaterials 9: 1409, https://doi.org/10.3390/nano9101409.Search in Google Scholar PubMed PubMed Central
Wimmer, R., Lucas, B.N., Tsui, T.Y., and Oliver, W.C. (1997). Longitudinal hardness and Young’s modulus of spruce tracheid secondary walls using nanoindentation technique. Wood Sci. Technol. 31: 131–141, https://doi.org/10.1007/bf00705928.Search in Google Scholar
Yu, Y., Tian, G.L., Wang, H.K., Fei, B.H., and Wang, G. (2011). Mechanical characterization of single bamboo fibers with nanoindentation and microtensile technique. Holzforschung 65: 113–119, https://doi.org/10.1515/hf.2011.009.Search in Google Scholar
Yusof, N.M., Tahir, P.M., Lee, S.H., and Khan, M.A. (2019). Mechanical and physical properties of cross-laminated timber made from acacia mangium wood as function of adhesive types. J. Wood Sci. 65: 20, https://doi.org/10.1186/s10086-019-1799-z.Search in Google Scholar
Zhang, Y., Liu, C., Wang, S.Q., Wu, Y., Meng, Y.J., Cui, J.Q., and Zhou, Z.B. (2015). The influence of nanocellulose and silicon dioxide on the mechanical properties of the cell wall with relation to the bond interface between wood and urea formaldehyde resin. Wood Fiber Sci. 47: 249–257.Search in Google Scholar
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