Improving properties of phenol- lignin- glyoxal resin as a wood adhesive by an epoxy resin

Kordkheili, Hamed Younesi; Pizzi, A.

doi:10.1007/s00107-020-01607-9

Cited by 23 publications

(8 citation statements)

References 22 publications

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“…In general, POC-x samples exhibited high water absorbability, compared with other polyester biomaterials including PCL (0.2% for 70 days), 30 PLA (0.45% for 30 days), 31 and PHA (4% for 60 days). 32 The saturated water absorption of POC-0 was even higher than that of PLG (13% for 2 days) 33 and PLGA (15.4% for 14 days), 34 which were two typical bulk-eroding polymers. Notably, POC-x also showed a fast diffusion rate of water (8∼16% for 60 h).…”

Section: Surface Hydrophilicity and Water Absorbability Investigation...mentioning

confidence: 99%

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation

Wan

Zhu

et al. 2022

Biomacromolecules

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As a biodegradable elastomer, poly(1,8-octanediolco-citrate) (POC) has been widely applied in tissue engineering and implantable electronics. However, the unclear degradation mechanism has posed a great challenge for the better application and development of POC. To reveal the degradation mechanism, here, we present a systematic investigation into in vivo and in vitro degradation behaviors of POC. Initially, critical factors, including chemical structures, hydrophilic and water-absorbency characteristics, and degradation reaction of POC, are investigated. Then, various degradation-induced changes during in vitro degradation of POC-x (POC with different cross-linking densities) are monitored and discussed. The results show that (1) cross-linking densities exponentially drop with degradation time; (2) mass loss and PBSabsorption ratio grow nonlinearly; (3) the morphology on the cross-section changes from flat to rough at a microscopic level; (4) the cubic samples keep swelling until they collapse into fragments from a macro view; and (5) the mechanical properties experience a sharp drop at the beginning of degradation. Finally, the in vivo degradation behaviors of POC-x are investigated, and the results are similar to those in vitro. The comprehensive assessment suggests that the in vitro and in vivo degradation of POC occurs primarily through bulk erosion. Inflammation responses triggered by the degradation of POC-x are comparable to poly(lactic acid), or even less obvious. In addition, the mechanical evaluation of POC in the simulated application environment is first proposed and conducted in this work for a more appropriate application. The degradation mechanism of POC revealed will greatly promote the further development and application of POC-based materials in the biomedical field.

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Section: Surface Hydrophilicity and Water Absorbability Investigation...mentioning

confidence: 99%

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation

Wan

Zhu

et al. 2022

Biomacromolecules

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“…For the second approach, lignin-glyoxal resins are prepared and mixed with petroleum-based cross-linking agents such as pMDI (polymeric 4,4′-diphenylmethane diisocyanate) to improve adhesion strength. , As an example of this strategy, a lignin-glyoxal resin was mixed with 40–60% pMDI by weight, and the resultant adhesives had shown to have adequate internal bond strength required for particleboard applications. , In other studies, up to 60 wt % of lignin-glyoxal resin was mixed with tannin extract solution and hexamethylenetetramine (hexamine) that act as a hardener to improve adhesion strength. , In one study using this approach, an adhesive was generated with a dry adhesion strength of 1.4 MPa, which was reported to be higher than industry standards ( i.e ., EN 314-2) for interior grade plywood . In the third approach, lignin-glyoxal resins were prepared using other cross-linking agents such as epichlorohydrin, polyacrylic ester, an aqueous polyurethane emulsion, or a commercial diglycidyl ether of bisphenol-A (DGEBA) epoxy resin. , …”

Section: Introductionmentioning

confidence: 99%

Lignin-Glyoxal: A Fully Biobased Formaldehyde-Free Wood Adhesive for Interior Engineered Wood Products

Siahkamari

Emmanuel

Hodge

et al. 2022

ACS Sustainable Chem. Eng.

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In this study, a biobased phenolic adhesive was successfully developed by entirely substituting both petroleumbased phenol and formaldehyde with an unmodified corn stover biorefinery lignin and glyoxal (a biobased dialdehyde), respectively. Lignin-glyoxal resins were synthesized using an alkaline catalyst with a molar ratio of lignin to glyoxal of 1:2. Chemical, thermal, and mechanical properties of the lignin, lignin-based resins, and final adhesives were assessed following appropriate standard test methods. The analysis of lignins and lignin-based resin molar mass was performed using gel permeation chromatography. The ligninglyoxal resin was found to have a 3-fold higher average molecular weight than the starting lignin, demonstrating the successful integration of lignin into the polymeric resin network. The curing of the formulated adhesives was studied using differential scanning calorimetry and dynamic mechanical analysis. Although the lignin-glyoxal resin had a higher curing temperature (167 °C) than a conventional phenol-formaldehyde resin (142 °C) and the formulated lignin-formaldehyde resin (146 °C), the rate and degree of cure were similar or better than the other two resins. The adhesion strengths of the formulated adhesives were determined using single-lap-joint veneer samples cured according to recommended press parameters for commercial adhesives. The lignin-glyoxal adhesive had a relatively high dry adhesion strength (3.9 MPa), with over 90% wood failure, but failed the wet adhesion test (boiling water test). Although the formulated lignin-glyoxal adhesive failed the boiling water test, it had excellent stability at room temperature water, remaining intact after 1 week during the water immersion test. The high dry adhesion strength makes this class of lignin-based formaldehyde-free adhesives a unique biobased glue for the production of interior grade plywood and oriented strand boards.

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“…Nowadays, the majority of particleboard panels are manufactured with urea-formaldehyde (UF) and phenol-formaldehyde (PF) resins. The use of UF and PF resins as wood adhesives has several advantages which have been mentioned in previous studies (Younesi-Kordkheili and Pizzi 2020a; Younesi-Kordkheili and Pizzi 2020b; Younesi-Kordkheili and Pizzi 2021). However, the panels produced with these types of adhesives cause carcinogenic formaldehyde emissions, which are known to have negative effects on human health in their service life and it is the greatest drawback of these adhesives (Conner 1996; Dunky 1997; Gonultas 2018; Yildirim et al 2021; Yildirim and Candan 2021).…”

Section: Introductionmentioning

confidence: 90%

Preparation and properties of a modified corn flour-lignin-glyoxal as a Green wood adhesive

Younesi-Kordkheili

Pizzi

2022

International Wood Products Journal

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A corn flourlignin-glyoxal (CLG) green wood adhesive was prepared by esterification and polyisocyanate prepolymer crosslinking of corn flour. At first corn flour was esterified by maleic anhydride and 10% polyisocyanate was added to it. The modified corn flour was then added at various contents (2, 4 and 6% on resin solids) to phenolated lignin and glyoxal solution to obtain the CLG resin. According to the FTIR spectra, the ester groups (-C=O) at 1730 cm-1 increased due to the esterification of corn flour by maleic anhydride. The addition of the modified corn flour significantly increased the viscosity and solid content and accelerated the gelation time of CLG resins. DSC analysis indicated that increasing the modified corn flour continuously decreases the gel onset and curing temperatures of the resin. Greater mechanical strength and higher dimensional stability of panels bonded with CLG resins can be obtained by modification of corn flour.

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Improving properties of phenol- lignin- glyoxal resin as a wood adhesive by an epoxy resin

Cited by 23 publications

References 22 publications

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation

Bulk Erosion Degradation Mechanism for Poly(1,8-octanediol-co-citrate) Elastomer: An In Vivo and In Vitro Investigation

Lignin-Glyoxal: A Fully Biobased Formaldehyde-Free Wood Adhesive for Interior Engineered Wood Products

Preparation and properties of a modified corn flour-lignin-glyoxal as a Green wood adhesive

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