scholarly journals A Comparison among Lignin Modification Methods on the Properties of Lignin–Phenol–Formaldehyde Resin as Wood Adhesive

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3502
Author(s):  
Hamed Younesi-Kordkheili ◽  
Antonio Pizzi
Keyword(s):  
Ionic Liquid ◽  
Maleic Anhydride ◽  
Dimensional Stability ◽  
Phenol Formaldehyde ◽  
Formaldehyde Emission ◽  
Gel Time ◽  
Bending Modulus ◽  
Lignin Modification ◽  
Solids Content ◽  
Modified Lignin

The research aim of this work is to determine the influence of lignin modification methods on lignin–phenol–formaldehyde (LPF) adhesive properties. Thus, glyoxal (G), phenol (P), ionic liquid (IL), and maleic anhydride (MA) were used to modify lignin. The modified lignins were used for phenol substitution (50 wt%) in phenol–formaldehyde adhesives. The prepared resins were then used for the preparation of wood particleboard. These LPF resins were characterized physicochemically, namely by using standard methods to determine gel time, solids content, density, and viscosity, thus the physicochemical properties of the LPF resins synthesized. The panels dimensional stability, formaldehyde emission, bending modulus, bending strength, and internal bond (IB) strength were also measured. MA-modified lignin showed by differential scanning calorimetry (DSC) the lowest temperature of curing than the resins with non-modified lignin and modified with IL, phenolared lignin, and glyoxal. LPF resins with lignin treated with maleic anhydride presented a shorter gel time, higher viscosity, and solids content than the resins with other lignin modifications. Equally, the particleboard panels prepared with LPF resins with maleic anhydride or with ionic liquid had the lowest formaldehyde emission and the highest mechanical strength among all the synthesized resins. The dimensional stability of all panels bonded with modified lignin LPF resins presented no difference of any significance.

scholarly journals Methods to improve lignin’s reactivity as a phenol substitute and as replacement for other phenolic compounds: A brief review

BioResources ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. 3515-3525 ◽  
Author(s):  
Lihong Hu ◽  
Hui Pan ◽  
Yonghong Zhou ◽  
Meng Zhang
Keyword(s):  
Phenolic Compounds ◽  
Chemical Structure ◽  
Phenol Formaldehyde ◽  
Paper Industry ◽  
Value Added ◽  
Pulp And Paper Industry ◽  
Lignin Modification ◽  
Modified Lignin ◽  
Lignin Macromolecule ◽  
Value Added Products

Lignin is readily available as a by-product from the pulp and paper industry. It is considered to be a promising substitute for phenol in phenol-formaldehyde (PF) resin synthesis, given the increasing concerns of the shortage of fossil resources and the environmental impact from petroleum-based products. One hurdle that prevents the commercial utilization of lignin is its low reactivity due to its chemical structure. Many efforts have been made to improve its reactivity by modification and/or depolymerization of lignin molecules. Methylolation and phenolation are the two most studied modification approaches aimed at introducing reactive functional groups to lignin molecules. Modified lignin from these two methods could partially replace phenol in PF resin synthesis. Demethylation of lignin could effectively increase the reactivity of lignin by forming catechol moieties in the lignin macromolecule. Other methods, including reduction, oxidation, and hydrolysis, have also been studied to improve the reactivity of lignin as well as to produce phenolic compounds from lignin. Most current methods of lignin modification are not economically attractive. One can expect that efforts will be continued, aimed at improving the utilization of lignin for value-added products.

scholarly journals Physico-mechanical properties of plywood bonded with ecological adhesives from Acacia mollissima tannins and lignosulfonates

2017 ◽  
Vol 78 (3) ◽  
pp. 34813 ◽  
Author(s):  
Naima Rhazi ◽  
Mina Oumam ◽  
Abdessadek Sesbou ◽  
Hassan Hannache ◽  
Fatima Charrier-El Bouhtoury
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Phenol Formaldehyde ◽  
Waste Product ◽  
Formaldehyde Emission ◽  
Extraction Methods ◽  
Press Temperature ◽  
Pulp Industry ◽  
Pressing Time ◽  
Chemical Conditions

The objective of this research was to develop ecological adhesives for bonding plywood panels using lignosulfonates, a common waste product of the wood pulp industry, and natural tannin extracted from Moroccan bark of Acacia mollissima using different process. Natural tannin and lignin were used in wood adhesives formulation to substitute resins based on phenol and formaldehyde. To achieve this, the lignosulfonates were glyoxalated to enhance their reactivity and the used tannins obtained by three different extraction methods were compared with commercial mimosa tannin. The proportion of Acacia mollissima tannins and lignosulfonates, the pressing time, the pressing temperature, and the pressure used were studied to improve mechanical properties, and bonding quality of plywood panel. The properties of plywood panels produced with these adhesives were tested in accordance with normative tests. Thus, the tensile strength, and the shear strength were measured. The results showed that the performance of the plywood panels made using biobased tannin adhesives was influenced by physical conditions such as pressure, press temperature as well as by chemical conditions, such as the tannin-lignin ratio. It exhibited excellent mechanical properties comparable to commercially available phenol-formaldehyde plywood adhesives. This study showed that biobased adhesives formulations presented good and higher mechanical performance and no formaldehyde emission.

Homogeneous Esterification of Xylan-Rich Hemicelluloses with Maleic Anhydride in Ionic Liquid

2010 ◽  
Vol 11 (12) ◽  
pp. 3519-3524 ◽  
Author(s):  
Xin-wen Peng ◽  
Jun-li Ren ◽  
Run-cang Sun
Keyword(s):  
Ionic Liquid ◽  
Maleic Anhydride

The effect of phenol-formaldehyde adhesive modification with fire retardant on the properties of birch plywood

2019 ◽  
Vol 106 ◽  
pp. 197-113
Author(s):  
JAKUB KAWALERCZYK ◽  
DOROTA DZIURKA ◽  
RADOSŁAW MIRSKI ◽  
ADRIAN TROCIŃSKI ◽  
MAREK WIERUSZEWSKI
Keyword(s):  
Weight Loss ◽  
Shear Strength ◽  
Phenol Formaldehyde ◽  
Fire Retardant ◽  
Solid Content ◽  
Burned Area ◽  
Gel Time ◽  
Bonding Quality ◽  
Resin Mixture ◽  
Gelling Time

The effect of phenol-formaldehyde adhesive modification with fire retardant on the properties of birch plywood. The study investigated how the modification of phenol-formaldehyde adhesive with a mixture of potassium carbonate and urea affect the properties of plywood. Based on the investigations of the viscosity, gel time and solid content of PF resin mixture containing various amounts of modifiers with various compositions it was found that modification led to major decrease in viscosity, caused the elongation of gelling time and reduced the solid content. In all variants modification of the resin led to significant improvement in plywood flammability evaluated on the basis of parameters such as: weight loss, time of ignition and burned area. The addition of fire retardant to the resin caused a decrease of shear strength. Composition of the modifier had a significant effect on bonding quality, however all plywood samples retained good values exceeding 1 N/mm2 required by EN 314-2 (1993).

Synthesis of Lignin-Based Epoxy Resin in Ionic Liquid [BMIm]Cl

2015 ◽  
Vol 740 ◽  
pp. 51-54
Author(s):  
Wen Ting Li ◽  
Ming Qiang Chen ◽  
Zhong Lian Yang
Keyword(s):  
Ionic Liquid ◽  
Epoxy Resin ◽  
Synthesis Temperature ◽  
Raw Material ◽  
Value Analysis ◽  
Alkali Lignin ◽  
Optimum Synthesis ◽  
Ft Ir ◽  
Modified Lignin ◽  
Epoxy Value

Industrial alkali lignin (LG) was used as raw material and ionic liquid 1-butyl 3-methylimidazolium chloride ([BMIm]Cl) was used as solvent. Alkali lignin was dissolved into the [BMIm]Cl and modified as propyl ether lignin(HLG). Then the HLG modified lignin was used to synthesizing the lignin-based epoxy resin (LGEP) with epoxy chloropropane. The structure of LG, HLG and LGEP were characterized with FT-IR, the results indicated that the propyl group was introduced to the LG and the reaction activity was improved. The expoxy value analysis results showed that the optimum synthesis temperature was 80°C and the epoxy value was 0.218.

scholarly journals Thermal Study of Anhydrides Cured Tetrafunctional Cardo Epoxy Resin

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jignesh P. Patel ◽  
Parsotam H. Parsania
Keyword(s):  
Thermal Properties ◽  
Maleic Anhydride ◽  
Epoxy Resin ◽  
Degradation Kinetics ◽  
Frequency Factor ◽  
Entropy Change ◽  
Thermal Study ◽  
Gel Time ◽  
Degradation Reactions ◽  
Different Types

Tetrafunctional cardo epoxy resin (EBCF) was cured by using 10 wt% maleic anhydride (MA), pyromellitic dianhydride (PMDA), phthalic anhydride (PA), tetrahydrophthalic anhydride (THPA), tetrabromophthalic anhydride (TBPA), and tetrachlorophthalic anhydride (TCPA) as hardeners at 120°C for 40–105 min (gel time) and then postcured 1 h at 130°C. Gel time is found to depend on the structure of the anhydrides used. Cured samples were found insoluble in common solvents. Cured and uncured EBCF were characterized by FTIR, DSC, and TGA techniques. Cured and uncured resins followed multistep degradation reactions. Kinetic parameters, namely, order of degradation, energy of activation, frequency factor, and entropy change, were determined according to the Anderson-Freeman method and interpreted in light of the nature of hardeners used for curing purpose. The resins followed integral or fractional order degradation kinetics. Complex degradation reactions are due to different types of linkages in cured resins. Both nature and structure of resin and hardeners affected the curing behavior and the resultant thermal properties of the cured resins.

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