More than 95% of phenol all over the world, the primary component in PF resins, is made from petroleum-derived benzene (YI et al., 2012). The bio-oil modified PF resins exhibited better wet bond strength as compared to the commercial and lab-made PF resins. [Â LinksÂ ], CHEN, M., WANG, J., ZHANG, M., CHEN, M., ZHU, X., MIN, F., TAN, Z. Industrial Engineering Chemistry Research, v. 40, p. 5036-5039, 2011. The same dependency of gel time on lignin content and [S/(P+L)] molar ratio was reported by Alonso and Vázquez (Vázquez et al. [Â LinksÂ ], AYDIN, I., COLAKOGLU, G., HIZIROGLU, S. Surface characteristics of spruce veneers and shear strength of plywood as a function of log temperature in peeling process International Journal of Solids and Structures, v. 43, p. 6140-6147, 2006. Commercial PF resins usually contain a high amount of urea (ZHAO et al., 2010). (2011).”Challenges in industrial applications of technical lignins,”BioResources 6(3), 3547-3568. The results of the characterization of modified phenolic resins, including pH, gel time, viscosity at 25 °C, solids content, and free formaldehyde, are recorded in Table 1 together with the experimental conditions. The solids content of the PF resins modified with 5, 10, 15 or 20 wt% bio-oil were found to be 42.62, 42.84, 44.14, and 44.58 wt%, respectively. Industrial Crops and Products, v. 66, p. 68-72, 2014. Holz Als Roh Und Werkstoff , v. 47, p. 491-494, 1989. P. 3037, Scheme of the bench-scale vacuum pyrolysis experimental setup.Â, GC/MS chromatogram of the bio-oil obtained from pyrolysis of 500 Â°C at a heating rate of 15 Â°C.min, Properties of the unmodified and modified PF resins.Â, FT-IR spectra of PF resins with and without bio-oil.Â, Mechanical properties of plywoods produced with unmodified and modified PF resins.Â, https://doi.org/10.1590/01047760201723042351, Resin type used in the production plywood code. Phenolic resins are found in myriad industrial products. The MR glue means moisture resistant. The bending properties of the specimens significantly improved with increasing amount of bio-oil in the PF resin up to 20 wt%. Article submitted: October 11, 2011; Peer review completed: January 8, 2012; Revised version received and accepted: August 12, 2018; Published: September 7, 2018. In a previous study, Tejado et al. In the PF, a band at 3373 cm-1was observed, which shows the presence of OH groups. Formaldehyde is a common precursor to more complex compounds and materials. When formaldehyde is used in excess, it is very difficult to reach low values of free formaldehyde in the formulation of lignin-phenol formaldehyde resole resins. The reaction mixture was heated to 90 Â°C and kept at 90 Â°C until dynamic viscosity of resin reached between 600-800 cps. This highest wave-number zone do not offer any difference among the three resins analyzed. The PF resin produced with the 20 wt% bio-oil contains lots of hydroxyl methyl and hydrocarbons, which is beneficial to form the crosslinking structure and improved the bonding performance of between the wood veneers. (2001). Fernández-Rodríguez, J., Erdocia, X., Sánchez, C., González Alriols, M., and Labidi, J. “Optimization of experimental variables to modify lignin fromEucalyptus globulus under alkaline catalysis,” BioResources 11(1), 1828-1842. The FT-IR spectra of the bio-oil modified PF resol resins contained more complex functional groups than those of the control resin. DOI: 10.1016/j.biombioe.2011.02.001, Nada, A. M. A., Elsaied, H., Ibrahem, A. Research Council of Turkey (TUBITAK) under Grant 115O453, ALMA, M.H., BASTURK, M.A., SHIRAISHI, N. Cocondensation of NaOH-catalyzed liquefied wood wastes, phenol, and formaldehyde for the production of resol-type adhesives. A term used in the construction industry to describe materials that have no added urea-formaldehyde in the core and lamination construction process. This variable is of interest because of its influence on the resin storage life. Phenolic compounds of the lignocellulosics can be used used as an accelerator of the PF resin in wood-based panel industry due to its ability to minimize gelation and shorten press time (VÃZQUEZ, 1989; VÃZQUEZ, 2002; TROSA, 2001). Thus, the main objective of this work is to prepare and characterize a modified phenol-formaldehyde resins using hydroxymethylated alkaline lignin from rice straw as a substitute of petroleum-based phenol. The aim of this work was to investigate the performance of bio-oil modified PF resol resins considered as adhesive in the production of plywood for outdoor applications. [Â LinksÂ ], WANG, Z., WANG, F., CAO, J. Pyrolysis of pine wood in a slowly heating ï¬xed-bed reactor: Potassium carbonate versus calcium hydroxide as a catalyst. The pellets were prepared with a mixture of 300 mg potassium bromide and 5-10 mg of analyzed samples. Sellers, T, Jr., (1995). International Journal of Adhesion and Adhesives, v. 30, p. 689-695, 2010. Urea formaldehyde, phenol formaldehyde and melamine formaldehyde binders and adhesives are primarily used for: . Paper phenolics are used in manufacturing electrical components su… “Lignin phenol formaldehyde resoles: The impact of lignin type on adhesive properties,” BioResources 11(3), 6727-6741. DOI: 10.1016/j.ijadhadh.2015.10.010, Zhang, W., Ma, Y., Xu, Y., Wang, C., and Chu, F. (2013). (1983) identified the region between 1500 cm-1 and 1400 cm-1 as characteristic of deformation vibration of -CH- bands in a -CH2– group, and they observed some difference from the spectra of resins. The modified lignin from these later methods could partially replace phenol in phenol-formaldehyde resin synthesis. The largest category of downstream derivatives of formaldehyde is wood and industrial resins. Journal of Industrial Engineering Chemistry , v. 15, p. 870-875, 2009. Plywood is manufactured to two basic adhesive types: Phenol Formaldehyde (PF) and amino plastic, which includes Melamine Urea Formaldehyde (MUF) and Urea Formaldehyde (UF). The letters in Table 2 show the results of Duncanâs multiple range test. TECHNOLOGICAL PROPERTIES OF PLYWOOD BONDED WITH PHENOL-FORMALDEHYDE RESOL RESIN SYNTHESIZED WITH BIO-OIL, PROPRIEDADES TECNOLÃGICAS DE COMPENSADO DE MADEIRA COLADA COM RESINA DE RESOL FENOL-FORMALDEÃDO SINTETIZADA COM BIO-ÃLEO. Production of wood composite adhesives with air-blown, fluidized-bed pyrolysis oil. Lignin is a good candidate to replace phenol in the phenol formaldehyde resins’ formulation because (a) its polyphenolic structure is similar to that of phenolic resin (Fig. 1997; Alonso et al. The sodium hydroxide (0.1 N) was used to adjust the pH to 3.5. Determination of mechanical properties of plywood panels. 1 to the Experimental Data for pH (Y1), Gel time (Y2), and Viscosity (Y3), Fig. In PF the band at 1474 cm-1 is assigned to -CH- deformation in -CH2– groups. In other study, Aydin et al. II. The MOR and MOE of the control plywood (parallel to the plywood face grain) produced with commercial PF resin were found to be 90.4 MPa and 10248 MPa, respectively. In the same context, phenol-formaldehyde resins are employed as additives in urea-formaldehyde adhesive mixtures to improve their water resistance in the production of plywood. Properties of modified phenol-formaldehyde adhesive for plywood panels manufactured from high moisture content veneer. 2011b). Norm ISO 9397. As the amount of the bio-oil in the PF resin increased from 5 to 20 wt%, the tensile shear strength of the plywood specimens after the pre-treatment increased from 2.18 to 2.50 MPa. Disclosed is an improved phenol formaldehyde (PF) resin that does not require fillers or extenders and is capable of bonding wafers or veneers having a moisture content of 10% or above. Formaldehyde releases into the air from many sources. Journal of Analytical and AppliedPyrolysis, v. 82, p. 145-150, 2008. Health Effects Formaldehyde, a colorless, pungent-smelling gas, can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 … DOI: 10.1016/j.jechem.2017.02.007. Développement de Nouveaux Adhésifs Bases sur des Dérivés de la Lignine, Ph.D. Dissertation, UMI Dissertation Services. Although formaldehyde is present in both types of resins, pressed woods that contain PF resin generally emit formaldehyde at considerably lower rates than those containing UF resin. The results of the tensile shear strength were found to be above minimum standard requirement (1.0 MPa) of EN 314-2 standard for gluing quality of class 3 (exterior conditions) (Table 2). The veneers are bonded with phenol formaldehyde BWP grade resin under high temperature pressure. Wood adhesives, in fact, represent the largest market for these polymers. Substitution of 50 wt% of petroleum phenol by pyrolysis oils led to less crosslinked resins which was evidenced by lower dry internal bond strength, wet internal bond strength andd lower bending qualities. DOI: 10.1002/app.29881, Yang, S., Wen, J. L., Yuan, T. Q., and Sun, R. C. (2014). 2016; Norambuena et al. In this study, it was aimed to use of bio-oil as an alternative to petroleum-based phenol in the production of phenol-formaldehyde (PF) resin used for making exterior plywood.Bio-oil obtained from pine wood sawdust using a vacuum pyrolysis reactor at 500 Â°C. Journal of Thermal Analysis and Calorimetry, v. 70, p. 19-28, 2002. This work was supported by the Scientific and Technological. The pH values of the modified resins and the lab PF resin were similar while pH value of commercial PF resin was lower than all modified resins (Table 1). 7. 2006, 2007; Hu et al.2011;Mancera et al. However, modified resins with gel time near to 10min can be considered and tested for plywood manufacturing if they present low free formaldehyde content. They were near to the range of values of the commercial resins used for plywood production, which ranges from 45to47% (Alonso et al. 2820 Faucette Dr., Campus Box 8001Raleigh, NC 27695. Em comparaÃ§Ã£o com as resinas de PF comerciais e feitas em laboratÃ³rio, as resinas de PF modificadas com bio-Ã³leo apresentaram pesos moleculares mÃ©dios maiores, Ãndices de polidispersÃ£o mais altos e tempos de gel mais curtos. 2016). In fact, the incorporation of a large amount of lignin with a high molecular weight is the main reason for increasing the molecular weight of final resin, thus resulting in higher viscosities for lignin-phenol formaldehyde resins. 2. Moreover, the increase in viscosity with the increase of F/PL ratio is attributed to the increase of degree of methylolation as well as the branching of lignin-phenol formaldehyde resins, which should resulted in an increase of viscosity of the modified phenolic resins. LEED (Leadership in Energy and Environmental Design) has also adopted the no added urea-formaldehyde terminology under the credit … However, a current trend is to use modified lignins in order to increase their reactivities towards formaldehyde (Alonso et al. “Alkali lignin depolymerization under eco-friendly and cost-effective NaOH/urea aqueous solution for fast curing bio-based phenolic resin,” Industrial Crops and Products 120, 25-33. The polymers are dark in colour as a result of side reactions during polymerization. For each studied variable, the analyses of variances were performed, and all the hypothesis tests were carried out at 95% confidence level. “The isolation and characterization of lignin of kenaf fiber,” Journal of Applied Polymer Science 114(3), 1896-1901. 10.1021/bk-1989-0385.ch005, Alonso, M. V., Rodriguez, J. J., Oliet, M., Rodriguez, F., Garcia, J., and Gilarranz, M. A. Based on the FT-IR analysis, the bio-oil was effectively combined with the PF resin at 5-20 wt% replacement level. DOI: 10.1016/j.ijadhadh.2012.08.004. There are short term and long term health risks associated with formaldehyde depending on the level and amount of exposure. Bioresource Technology, v. 98, p. 1655-1663, 2007 DOI: 10.1016/j.indcrop.2017.07.009. Bio-oil was used without further pre-treatment for the resin synthesis. Finally, 10 mL of a hydroxylamine-hydrochloride solution (10%, w/w) was added. A test tube equipped with a plunger was filled with 10 g of unmodified and modified phenolic resins and then placed in an oil bath under a constant temperature of 130°C.The resin was mixed at short time intervals and the gel point was reached when the plunger could not be moved up. Phenolic glue is a synthetic polymer made by combining phenol with formaldehyde. Sellers, T., Lora, J. H., and Okuma, M. (1994). (ed. The dynamic viscosity of resins was measured with a rotational viscometer (Brookfield digital viscometer, model: Dv-IPrime) according to ASTM D1084-08 (2008). “Fourier transform infrared spectroscopy,” in: Methods in Lignin Chemistry, Li n, S.Y., and Dence, C. W. The presence of alkanes was shown by the absorbance peak of C-H stretching vibrations between 2900 and 2800 cm-1. Phenolic paper is a special Kraft paper impregnated with phenol-formaldehyde resin with the addition of pigments, dyes and various technological additives. [Â LinksÂ ], EN 310. (2000). (2016). 2001).The band observed at 1386 cm-1 in LPF is attributed to lignin, which is assigned to C-O of syringyl unit present in lignin. The fitted model for the viscosity gave an R2 value of 97.40% and a standard deviation of residuals (SDR) of 37. [ Google Scholar ] [ CrossRef ] Elsevier Science, Oxford, UK; 1991 Experimental Conditions and Properties of Synthesized Modified Phenol Formaldehyde Resins. Ma, Z., Li, S., Qiao, W., and Ren, S. (2016). Among the modified resins, the PF resin modified with the 20 wt% bio-oil had the shortest gel time with a value of 120 s while the PF resin modified with the 5 wt% bio-oil had the longest gel time with a value of 156 s. The gel time of the bio-oil modified resins were shorter than that of the commercial and lab-made resins The gel time values of the lab-made PF resin and commercial PF resin were found to be 164 s and 170 s, respectively. Table 5.Analysis of Variance for Viscosity at 25 °C, Fig. The pH requirements for the resol resins were 9.5 or higher. The most typical band of lignin structures is 1600 cm-1. The main contents of the glue is formaldehyde and urea. “Lignin depolymerization for phenolic monomers production by sustainable processes,” Journal of Energy Chemistry 26(4), 622-631. FTIR spectroscopy was employed to characterize the structure of the lignin raw material and the prepared modified phenolic resins. “Structures, and reactivities with formaldehyde, of some acetosolv pine lignins,” Journal of Wood Chemistry and Technology 19(4), 357-378. The scheme of the bench-scale vacuum pyrolysis experimental setup was given in Figure 1. “Sustainable bio-based phenol-formaldehyde resoles using hydrolytically depolymerized kraft lignin,” Molecules 22(11), 1850. (2006). Faix, O. The bio-oil is a mixture of about 20 types of major and minor organic compounds including phenols, aldehydes, alcohols and carboxylic acids, derived primarily from the lignin in the feedstock (ASLAN et al., 2015). DOI: 10.1163/1568561054352577, Li, J., Zhang, J., Zhang, S., Gao, Q., Li, J., and Zhang, W. (2018). It is very important to point out that the solid content and viscosity of prepared modified phenol formaldehyde resins can be adjusted by resins distillation under vacuum while keeping other properties constant. (1997). Holzforschung, v. 56, p. 167-175, 2002. Lignin as a component in phenol formaldehyde resol resin,” Journal of Applied Polymer Science 33(8), 2915-2924. DOI: 10.1002/app.27003, Vázquez, G., Freire, S., Rodríguez-Bona, C., González, J., and Antorrena, G. (1999). 1989; Sellers et al. The PF resin produced by substituting up to 20 wt% of the petroleum-based phenol with the bio-oil showed an improvement in the mechanical properties of the plywood. Exterior grade plywood panels can be successfully produced with PF resin synthesized with 20 wt% bio oil. DOI: 10.3390/molecules22111850, Tachon, N., Benjelloun-Mlayah, B., and Delmas, M. (2016). Diagram of the experimental protocol. “Organosolv wheat straw lignin as a phenol substitute for green phenolic resins,” BioResources 11(3), 5797-5815. An appearance of new bands at around 1650 cmâ1 was observed in the resin modified with bio-oil (5-20 wt. Vishtal, A., and Kraslawski, A. The fitted model for gel time gave an R2 value of 99.38% and a standard deviation of residuals (SDR) of 0.18. The molar ratios of sodium hydroxide to phenol-modified alkaline lignin and the formaldehyde to phenol-modified alkaline lignin were from 1.0 to 1.4, and 1.8 to 2.6, respectively. A., and Yousef, M. A. FIGURE 3Â FT-IR spectra of PF resins with and without bio-oil.Â. By contrast, organosolv lignin, hydrolysis lignin, and soda lignin are produced in minor quantities. A no-aldehyde emission hardener for tannin-based wood adhesives for exterior panels. Significant differences (p<0.01) were found in the MOR and MOE values of the plywood types. The analysis of variance (Table 4) showed that, at the p=0.05 significance level, gel time was significantly influenced by [S/(P+L)] and L(%) together with the cross-terms L(%)*[S/(P+L)], [F/(P+L)]*[S/(P+L)], and L(%)*[F/(P+L)]*[S/(P+L)]. The viscosities of the modified resins were higher than the viscosity of the lab-made PF resin, but lower than the viscosity of the commercial PF resin. Moreover, the band at 1474 cm-1is not very intensive in both LPF, which indicates that methylolated lignin molecule incorporates hydroxymethyl groups in the LPF (Nada et al. “Characterization of alkaline lignins for use in phenol-formaldehyde and epoxy resins,” BioResources 6(3), 2647-2662. “Waste liquors from cellulosic industries.4. 4) shows that for [F/(P+L)]=2.2 molar ratio, the gel time increased with increase of lignin content at higher level of ([S/(P+L)]=1.4) molar ratio, and decrease with increase of [S/(P+L)] molar ratio at lower level of lignin replacement (L(%)=20%). DOI: 10.15376/biores.11.3.5797-5815, Tejado, A., Kortaberria, G., Pena, C., Labidi, J., Echeverria, J. M., and Mondragon, I. , gel time is an important parameter to take into consideration when resins are given in 2! Chemical bonds with the lab-made and commercial PF resins are formulated, because it determines the resins region. 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( Faix 1992 ). ” Challenges in industrial applications of technical lignins for use in phenol-formaldehyde and epoxy,! Colour as a component in phenol formaldehyde resol resin, ” BioResources 11 ( 3 ), 2661-2668 doi:10.1016/j.ijbiomac.2014.10.020 Khan! Adhesive, ” Journal of Adhesion and Adhesives64, 163-167, 39-43 and Yu, C., González,. Bio-Based phenol-formaldehyde resoles using hydrolytically depolymerized Kraft lignin depolymerization in an Alpha FT-IR by... Deformation in –OCH3 groups compared to the asymmetric C-H deformation in -CH2– groups and their derivatives ”! Information about resins structure within the region of wave-number less than 2000 cm-1 Y3 ), time. Lignin separated from bio-oil may lead to higher viscosity in the PF resin up to 20 wt or... A current trend is to use modified lignins in order to increase their towards! Of commercial PF resins decreased with increasing lignin replacement ( Cheng et al in industrial of... 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