Eucalyptus bark lignin substituted phenol formaldehyde adhesives: A study on optimization of reaction parameters and characterization

Abstract

The major adhesive resin worldwide used in the manufacture of plywood is phenol formaldehyde resole (PF) resin. The raw material for this kind of adhesive is derived from petroleum oil. Because of rising prices of crude oil and the scarcity of petroleum products, their replacement by natural resource-based raw material has become a necessity. In the present work, the possibility of replacing phenol in PF resin with lignin was explored. The parameters for preparation of bark lignin substituted PF (LPF) adhesive, such as lignin concentration, formaldehyde to phenol molar ratio, catalyst concentration, reaction time, and reaction temperature, were optimized. It was found that up to 50 wt % of phenol can be substituted by lignin to give an LPF adhesive with better bonding strength compared to that of control PF resin. Prepared resins were characterized using IR, DSC, and TGA. IR spectra of LPF adhesive showed structural similarity with that of PF adhesives. Thermal stability of LPF adhesive was found to be lower compared to that of control PF (CPF) adhesive. DSC studies revealed a lower curing temperature for LPF resin than that for CPF resin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3514 -3523, 2004

Formulation of an Environmentally Friendly Adhesive for Wood

“…CPF is indicative of a C-O stretching vibration while the peak of frequency 1115 cm À1 shows the presence of ether aliphatic through asymmetric stretching vibration for C-O-C. [17] Both the lignin-phenol adduct and the LPF resin have similar peaks at band 1470 cm À1 indicating the presence of a methylene bridge. [18] However, this band is not present in the CPF resin. Furthermore, two bands at 2900 and 2800 cm À1 in the lignin-phenol adduct and LPF spectra signify the presence of CH stretching.…”

“…Finally, the confirmed presence of lignin in both the lignin-phenol adduct and LFP compounds is indicated by the CH stretching in syringyl and the presence of C-O primary alcohol at bands 1113 and 1115 cm À1 respectively. [18] The tensile strength results for both CPF and LPF adhesive bonds were analysed in order to measure the bonding strength between the adhesive and the wood substrate. Table 1 and Table 2 show the results of the ultimate tensile strengths tests for LPF and CPF respectively.…”

Sal (Shorea Robusta) Leaves Lignin Epoxidation and Its Use in Epoxy Based Coatings

“…The use of lignin for the synthesis of new polymeric materials is the most promising alternative for its revalorization. There has been extensive research for the replacement of phenol in phenol formaldehyde resin due to its similar structure [7][8][9] . One of the major challenges is the replacement of less reactive lignin due to highly substituted structure in phenol formaldehyde resin system 10 .…”

Cure Kinetics, Bonding Performance, Thermal Degradation, and Biocidal Studies of Phenol-Formaldehyde Resins Modified with Crude Bio-oil Prepared from Ziziphus mauritiana Endocarps

“…It is generally believed that lower activation energy is needed for high Mw resins to cure (Park et al 1998;Anwar et al 2009;Wahab et al 2012), meaning thereby that high Mw resins would cure at low temperatures. The initial decrease in curing temperature and the E may be also be attributed to promotional catalytic effect of lingo-cellulosic derivatives present in the bio-oil on the cure reaction, as reported by some other studies (Vázquez et al 2002;Turunen et al 2003;Khan et al 2004;Lei and Wu 2006;Wang et al 2009a;Hu et al 2013). The role of bio-oil as an efficient crosslinking agent due to presence of multiple reactive sites (Hu et al 2013) may also be taken as a reason for such decrease in Tp and E of the curing reaction.…”