Abstract
The effect of ultraviolet (UV) light irradiation on the color and chemical structure of water-cured polymeric diphenylmethane diisocyanate (PMDI) was investigated using a UV long-life fade meter. Control treatment was performed without UV light irradiation using a thermohygrostat for comparison. Two kinds of resin were used in this study: that to which only water had been added, and resin to which a small amount of polyol and water had been added. In addition, lauan (Shorea spp.) wood was used as a reference. The photodegradation of the resins over a period of up to 300 h was observed using a colorimeter and Fourier transform infrared (FT-IR) spectroscopy. When the resins were treated with UV light, the color difference (ΔE * ab) of the resins increased signifi cantly in a short time, and then reached a near-constant value. For lightness, L * decreased rapidly for a few hours and then decreased gradually. The color darkened compared with that of the wood used. When treatment was performed without UV light irradiation, ΔE * ab and ΔL * of the resins showed negligible change. Based on the results of FT-IR analysis, severe degradation such as cleavage of the main chemical bond was hardly observed under UV light irradiation irrespective of the type of resin.
Article PDF
Similar content being viewed by others
References
Umemura K, Takahashi A, Kawai S (1998) Durability of isocyanate resin adhesives for wood I: thermal properties of isocyanate resin cured with water. J Wood Sci 44:204–210
Umemura K, Takahashi A, Kawai S (1999) Durability of isocyanate resin adhesives for wood II: effect of the addition of several polyols on the thermal properties. J Appl Polym Sci 74:1807–1814
Umemura K, Kawai S (2002) Effect of polyol on thermo-oxidative degradation of isocyanate resin for wood adhesives. J Wood Sci 48:25–31
Umemura K, Kawai S (2002) Durability of isocyanate resin adhesives for wood III: degradation under constant dry heating. J Wood Sci 48:380–386
Umemura K, Takahashi A, Kawai S (2002) Durability of isocyanate resin adhesives for wood IV: degradation under constant steam heating. J Wood Sci 48:387–393
Thapliyal BP, Chandra R (1991) Photostability of polyetherurethaneureas. Polym Int 24:7–13
Hoyle CE, Shah H, Moussa K (1996) Photolysis of methylene 4,4′-diphenyldiisocyanate-based polyurethane ureas and polyureas. Polym Durability 249:91–111
Shah H, Hoyle CE (1993) Photodegradation of MDI based polyurethane/urea elastomers. Polym Mater Sci Eng 68:74–75
Bajsic EG, Rek V, Sendijarevic A, Sendijarevic V, Frish KC (1996) The effect of different molecular weight of soft segments in polyurethanes on photooxidative stability. Polym Degrad Stab 52: 223–233
Wilhelm C, Rivaton A, Gardette JL (1998) Infrared analysis of the photochemical behavior of segmented polyurethanes. Polymer 39:1223–1232
Furukawa M, Wakiyama K (1999) Deterioration of novel polyesterurethane elastomers in outdoor exposure. Polym Degrad Stab 65:15–24
Wilhelm C, Gardette J-L (1997) Infrared analysis of the photochemical behavior of segmented polyurethanes: 1 aliphatic poly(ester-urethane). Polymer 38:4019–4031
Nzokou P, Kamdem DP (2006) Influence of wood extractives on the photo-discoloration of wood surfaces exposed to artificial weathering. Color Res Appl 31:425–434
Hon DN-S, Clemson SC, Feist WC (1986) Weathering characteristics of hardwood surfaces. Wood Sci Technol 20:169–183
Pastore TCM, Santos KO, Rubim JC (2004) A spectrocolorimetric study on the effect of ultraviolet irradiation of four tropical hardwoods. Bioresource Technol 93:37–42
Minemura N, Umehara K (1979) Color conditioning of wood I (in Japanese). Rep Hokkaido Forest Prod Res Inst 68:92–145
Tolvaj L, Mitsui K (2005) Light source dependence of the photodegradation of wood. J Wood Sci 51:468–473
Singh RP, Tomer NS, Bhadraiah SV (2001) Photo-oxidation studies on polyurethane coating: effect of additives on yellowing of polyurethane. Polym Degrad Stab 73:443–446
Athawale AA, Deore BA, Kulkarni MV (1999) Spectroscopic and electrochemical properties of poly(2,5-dimethyl aniline) films. Mater Chem Phys 60:262–267
Hari SN (1991) Structural determination of a semiconductive tetramer of aniline by IR, UV-visible, ESR, XPS and mass spectroscopy techniques. J Mater Sci 26:1683–1690
Angela Z, Lothar D (1997) Investigation of the electropolymerization of aniline by the in situ techniques of attenuated total reflection (ATR) and external reflection (IRRAS). J Mol Struct 410–411:165–171
Author information
Authors and Affiliations
Corresponding author
Additional information
Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, Japan, and at the 6th International Wood Science Symposium, Bali, Indonesia
About this article
Cite this article
Umemura, K., Yamauchi, H., Ito, T. et al. Durability of isocyanate resin adhesives for wood V: changes of color and chemical structure in photodegradation. J Wood Sci 54, 289–293 (2008). https://doi.org/10.1007/s10086-008-0948-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10086-008-0948-6