As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(H...As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(HKL)is limited due to its poor crosslinking reactivity.Hence,for the first time,the present study reports the facile oxidation of HKL involving a redox reaction with silver-ammonia complexes([(AgNH3)2]+),primarily focusing on oxidation to produce reactive quinones and promote C-C linkages during reaction.This study aims to increases reactivity of oxidized HKL for effective crosslinking with monoethanolamine(MEA)for the development of bio-based wood adhesives.The characterization,including 13C-nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy,confirms the oxidation reaction,such as the formation of quinones(C=O)and subsequent crosslinking between the oxidized HKL molecules and MEA.Additionally,gel permeation chromatography(GPC)confirms the C-C and C-O linkages with increased molecular weight after oxidation,and is supported by differential scanning calorimetry(DSC)which shows the exothermic reaction due to the crosslinking of the oxidized HKL molecules via condensation to form C-C and C-O linkages.The crosslinked HKL/MEA-based adhesives underwent mild reaction and achieved a maximum dry shear strength of 0.77 MPa,which exceeds the standard requirement of 0.6 MPa.These findings demonstrate not only a one-pot oxidation for improving the reactivity of HKL using silver complexes,but also its facile crosslinking with MEA for sustainable bio-based wood adhesives.展开更多
Nanocellulose-based adhesives are gaining attention as a viable alternative to conventional adhesives,offering benefits such as cost-effectiveness and scalability,which make them suitable for various sectors,including...Nanocellulose-based adhesives are gaining attention as a viable alternative to conventional adhesives,offering benefits such as cost-effectiveness and scalability,which make them suitable for various sectors,including cosmetics,pharmaceuticals,biodegradable products,and as reinforcing agents in natural adhesives.This review delves into the current advancements in nanocellulose-based adhesive solutions for sustainable and eco-friendly wood composites,using systematic review methods and bibliometric analysis.Data were collected from the Scopus database,spanning from 2007 to 2024,and visualized using VOSviewer to highlight emerging trends in the field.The analysis revealed that nanocellulose shows great potential as a reinforcing component for traditional adhesives used in wood products such as phenol-formaldehyde(PF),urea-formaldehyde(UF),polymeric diphenylmethane diisocyanate(pMDI),and melamine-urea adhesives.Nanocellulose,derived from the most abundant biopolymer,cellulose,has been utilized in its nanoscale form for adhesive applications.This review emphasizes the advancements in using cellulose nanocrystals(CNC)and cellulose nanofibrils(CNF)to develop sustainable adhesives.It explores both the challenges and future prospects for large-scale production and application of nanocellulose-based adhesives.展开更多
基金supported by the National Research Foundation(NRF)of Korea,funded by the Korean Government(MSIT)(Grant No.RS-2023-00240043).
文摘As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(HKL)is limited due to its poor crosslinking reactivity.Hence,for the first time,the present study reports the facile oxidation of HKL involving a redox reaction with silver-ammonia complexes([(AgNH3)2]+),primarily focusing on oxidation to produce reactive quinones and promote C-C linkages during reaction.This study aims to increases reactivity of oxidized HKL for effective crosslinking with monoethanolamine(MEA)for the development of bio-based wood adhesives.The characterization,including 13C-nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy,confirms the oxidation reaction,such as the formation of quinones(C=O)and subsequent crosslinking between the oxidized HKL molecules and MEA.Additionally,gel permeation chromatography(GPC)confirms the C-C and C-O linkages with increased molecular weight after oxidation,and is supported by differential scanning calorimetry(DSC)which shows the exothermic reaction due to the crosslinking of the oxidized HKL molecules via condensation to form C-C and C-O linkages.The crosslinked HKL/MEA-based adhesives underwent mild reaction and achieved a maximum dry shear strength of 0.77 MPa,which exceeds the standard requirement of 0.6 MPa.These findings demonstrate not only a one-pot oxidation for improving the reactivity of HKL using silver complexes,but also its facile crosslinking with MEA for sustainable bio-based wood adhesives.
基金funded by the Research Collaboration Center for Biomass and Biorefinery,Universitas Padjadjaran and BRIN,Indonesia,Grant Number 2534/II.7/HK.01.00/5/2023 and B-723/II.7/HK.01.00/4/2024.
文摘Nanocellulose-based adhesives are gaining attention as a viable alternative to conventional adhesives,offering benefits such as cost-effectiveness and scalability,which make them suitable for various sectors,including cosmetics,pharmaceuticals,biodegradable products,and as reinforcing agents in natural adhesives.This review delves into the current advancements in nanocellulose-based adhesive solutions for sustainable and eco-friendly wood composites,using systematic review methods and bibliometric analysis.Data were collected from the Scopus database,spanning from 2007 to 2024,and visualized using VOSviewer to highlight emerging trends in the field.The analysis revealed that nanocellulose shows great potential as a reinforcing component for traditional adhesives used in wood products such as phenol-formaldehyde(PF),urea-formaldehyde(UF),polymeric diphenylmethane diisocyanate(pMDI),and melamine-urea adhesives.Nanocellulose,derived from the most abundant biopolymer,cellulose,has been utilized in its nanoscale form for adhesive applications.This review emphasizes the advancements in using cellulose nanocrystals(CNC)and cellulose nanofibrils(CNF)to develop sustainable adhesives.It explores both the challenges and future prospects for large-scale production and application of nanocellulose-based adhesives.
