This review is composed of three main parts each of which is written by well-known top specialists that have been,in a way or other,also the main participants of the majority of the developments reported.Thus,after a ...This review is composed of three main parts each of which is written by well-known top specialists that have been,in a way or other,also the main participants of the majority of the developments reported.Thus,after a general part covering the grand lines and more in-depth views of more recent tannin,lignin,carbohydrate and soy bioadhesives,somemix of the other bio raw materials with soy protein and soy flour and some other differently sourced bioadhesives for wood,this review presents a more in-depth part on starch-based wood adhesives and a more indepth part covering plant protein-based adhesives.It must be kept in mind that the review is focused on completely or almost completely biosourced adhesives,the fashionable adhesives derived from mixes of biosourced materials with synthetic resins having been intentionally excluded.This choice was made as the latter constitute only an intermediate interval,possibly temporary if even for a somewhat long times,towards a final full bioeconomy of scale in this field.This review also focuses on more recent results,mainly obtained in the last 10–20 years,thus on adhesive formulations really innovative and sometimes even non-traditional.In all these fields there is still a lot of possibility of innovation for relevant formulation as this field is still in rapid growth.展开更多
Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the ...Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the heart of these advances lies a critical,often defining factor:the interface.Whether between polymers and solid substrates,liquids,gases,or other polymers,interfacial phenomena govern adhesion,wetting,energy dissipation,chemical reactivity,and signal transmission.Interfaces are not passive boundaries but active zones of complexity and function,where molecular interactions shape material performance at every scale—from nanometers to entire devices.展开更多
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
Since 2009,perovskite solar cells(PSCs)have advanced significantly,achieving over 26%efficiency for single-junction devices and exceeding 34%for silicon-perovskite tandem cells.Despite these successes,the weak adhesio...Since 2009,perovskite solar cells(PSCs)have advanced significantly,achieving over 26%efficiency for single-junction devices and exceeding 34%for silicon-perovskite tandem cells.Despite these successes,the weak adhesion of C_(60)to perovskite layers,due to van der Waals interactions,hinders long-term stability.In this study,we introduce electron-deficient intermolecular adhesives(EDIAs)as a novel interlayer material to enhance adhesion between perovskite and C_(60)layers.Comprehensive analyses,including density functional theory calculations,microscopy,and spectroscopy,demonstrate that EDIAs,particularly NDI-C9-Ace comprising of three key functionalities:aπ-electron-deficient arene core,a hydrophobic passivation core,and a secondary-bond anchoring core,significantly improve bonding strength and recombination passivation.This leads to enhanced efficiency as well as enhanced mechanical and photochemical stability in PSCs.Long-term stability tests further confirm the superior durability of EDIA-enhanced devices.This study highlights EDIA as a promising strategy for enhancing the robustness and efficiency of PSCs.展开更多
Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermo...Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.展开更多
Face centred cubic（FCC） TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives（ECAs） with the polymer matrix.Electrically conductive ...Face centred cubic（FCC） TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives（ECAs） with the polymer matrix.Electrically conductive properties of the ceramic ECAs were studied.The bulk electrical resistivity varied with the powder content of the FCC-TiB in ECAs.The FCC-TiB filled ECAs also showed the percolation behavior that usually occurred for the metal-filled ECAs,the percolation threshold was located at the content of 60%FCC-TiB.A minimum value of 0.1 Ω·cm was obtained at a content of 75%FCC-TiB.In order to check the reliability of mechanical property,tensile test was done to measure the shear strength,and the shear strength dropped with increasing the content of FCC-TiB powders.It is about 12.26 MPa at the content of 70%TiB powders.The Cu filled ECAs were also prepared for comparison.The properties of the oxidation resistance of the two ECAs were evaluated.The results show that the ceramic ECAs have excellent oxidation resistance and better stability compared with the Cu filled ECAs.展开更多
The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing ad...The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.展开更多
We aim to present an overview of the status of adhesives in the wood industry, especially in the area of wood-based panels. The review summarizes the current state of research of two kinds of adhesives, i.e., syntheti...We aim to present an overview of the status of adhesives in the wood industry, especially in the area of wood-based panels. The review summarizes the current state of research of two kinds of adhesives, i.e., synthetic adhesives and natural adhesives. Synthetic adhesives, consisting of urea-formaldehyde resins （UF）, phenol-formaldehyde resins （PF）, polyvinyl acetate emulsion （PVAc） and isocyanates, are widely used. For UF, most investigations are concerned with the reduction of free formaldehyde; for PF, most studies focus on finding new chemicals to replace phenol. PVAc has poor properties, but these can be improved by a blending reactions and copolymerization with other chemicals. Isocyanate is an environmentally friendly synthetic adhesive, but also suffers from inadequate properties. Natural adhesives, such as protein/starch, lignin and tannins, have poor bonding effect that limits their level of use, but their main advantages are that they are environmentally friendly and a renewable resource. Studies of modification can improve the bonding performances and gradually cause natural adhesives to become applied in industrial production. Some proposals for future development and the importance of environmentally friendly adhesives are provided, which will be helpful in future theoretical and experimental research.展开更多
The curing process of two biobased adhesives:pine tanninhexamine(TH)and organosolv lignin non-isocyanate polyurethane(NIPU),suitable for interior nonstructural use,were compared with commercial urea-formaldehyde(UF)ad...The curing process of two biobased adhesives:pine tanninhexamine(TH)and organosolv lignin non-isocyanate polyurethane(NIPU),suitable for interior nonstructural use,were compared with commercial urea-formaldehyde(UF)adhesive.Changes in chemical structure before and after the curing process were observed with Fouriertransform infrared spectroscopy(FTIR).The process of adhesive curing was monitored with differential scanning calorimetry(DSC)and the automated bonding evaluation system(ABES).Both DSC and ABES measurements confirmed UF as the fastest and NIPU as the slowest curing adhesive observed.Taking into account the ABES results,the optimal pressing parameters for the TH adhesive would be 4 min at 175℃,for the NIPU adhesive 7 min at 200℃and for the UF 1.5 min at 100℃.Strong linear correlation was observed between mechanical and chemical curing for the UF and NIPU adhesives,whereas lower correlation was observed for the TH adhesive.At all observed adhesives,the DSC measurements were underestimating the curing process determined by ABES in the first part and overestimating it at the end.The underestimation was the most evident with the TH adhesive and the less with the UF adhesive.When comparing the uncured and cured FTIR spectra of all three types of adhesives,a drastic decrease in the characteristic band of-OH groups at 3330–3400 cm^(−1)and an increase in the signal intensity at 2920 cm^(−1)of aliphatic-CH2-groups were observed.For the UF adhesive,the C=O stretching frequency has shifted from 1632 cm^(−1)for uncured to three different bands at 1766,1701,and 1655 cm^(−1)for cured UF.The sharp band for phenolic alcohols at 1236 cm^(−1)of C–O stretch and hydroxyl O–H functional group at 1009 cm^(−1)and at 684 cm^(−1)of uncured TH adhesive diminished during curing,which indicates that a crosslinking reaction occurs via-OH groups.The peak of the C=O group of urethane bridges at 1697 cm^(−1)for uncured NIPU shifted to lower wavenumber at 1633 cm^(−1)for cured NIPU.展开更多
Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched...Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched oligomers were obtained and identified,indicating how such oligomer structures could further cross-link to form a hardened network.Unusual structures were observed,namely carbamic acid-derived urethane linkages coupled with lactam structures.The curing of the adhesive was followed by thermomechanical analysis(TMA).It appeared to follow a two stages process:First,at a lower temperature(maximum 130℃),the growth of linear oligomers occurred,finally forming a physically entangled network.This appeared to collapse and disentangle,causing a decrease of MOE,as the temperature increases.This appears to be due to the ever more marked Brownian movements of the linear oligomer chains with the increase of the temperature.Second,chemical cross-linking of the chains appeared to ensue,forming a hardened network.This was shown by the thermomechanical analysis(TMA)showing two distinct MOE maxima peaks,one around 130℃ and the other around 220℃,with a very marked MOE decrease between the two.Plywood panels were prepared and bonded with the SPI-NIPU wood adhesive and the results obtained are presented.The adhesive appeared to pass comfortably the requirements for dry strength of relevant standards,showing to be suitable for interior grade plywood panels.It did not pass the requirements for wet tests.However,addition of 15%of glycerol diglycidyl ether improved the wet tests results but still not enough to satisfy the standards requirements.展开更多
The electrochemical migration (ECM) behavior of the electrically conductive adhesives (ECAs) filled with pure Ag powder or Ag-plated Cu composite powder with varied Ag:Cu ratios was investigated under the condition of...The electrochemical migration (ECM) behavior of the electrically conductive adhesives (ECAs) filled with pure Ag powder or Ag-plated Cu composite powder with varied Ag:Cu ratios was investigated under the condition of applying constant voltage and distilled water environment.ECM resistance was determined from the current-time curves.The microstructure and composition of ECM dendrite products were analyzed by SEM/EDS and XRD.It was found that the ECM resistance of Ag-plated Cu composite powder-filled ECAs was evidently higher than that of pure Ag powder-filled ECAs.The Ag:Cu ratio of composite powder in ECAs had notable influence on ECM resistance,which was enhanced with the decrease of Ag:Cu ratios.The composition of dendrites formed between cathode and anode during ECM process was not uniform for Ag-plated Cu-filled ECAs.An ECM inhibiting mechanism of Ag-plated Cu composite powder was proposed according to analysis of the electrochemical impedance spectroscopy,Tafel plot and dendrite composition.展开更多
This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a fill...This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a filler loading of 78 wt.%,83 wt.%and 88 wt.%and cured at 150℃and 180℃,respectively.The results show that the electrical and thermal conductivities of ECAs were improved with the increasing of filler loading and curing temperature.Adding silver NPs in silver flakes negatively affected the electrical and thermal conductivities of ECAs at a low filler mass fraction of 78 wt.%,because the segregation of NPs enlarged the average distance of silver flakes;while it positively influenced the electrical and thermal conductivities of ECAs at a loading ratio of 88 wt.%,probably due to NPs filling in the gaps between silver flakes or even sintering together with each other or with silver flakes,especially when curing at high temperature of 180℃.展开更多
Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was...Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was manufactured in this study.The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested,respectively,on a smooth glass and a printed circuit board(PCB)with different surface structures.The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bioinspired adhesives.The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2−5 times,and due to the use of variable modulus of PVC gel,the surface micropillars can maintain high aspect ratio and flexible tips at the same time.Moreover,the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation.An adhesion-desorption device was made according to the movement of the gecko toes,and the PCB was successfully grasped.展开更多
Increasing global energy crisis and scarcity of petroleum resources has shifted focus of chemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as p...Increasing global energy crisis and scarcity of petroleum resources has shifted focus of chemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as petroleum and natural gas [1] [2], would be gradually replaced by renewable biopolymers. Starch is a relatively inexpensive and renewable product from abundant plants, easy processing and it has been extensively used as binders, sizing materials, glues and pastes [3], but its bonding capacity is not strong enough to glue wood [4]. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of starch-based adhesives. In starch-based wood adhesive many new approaches have come forward for effective use it in wood/wood composite adhesive giving comparable performance as synthetic adhesives. This review of starch-based adhesives is made with the focus on starch modification methods for improving properties of starch-based adhesives.展开更多
Design of rapidly detachable adhesives with high initial bonding strength is of great significance but it is full of great challenge. Here, we report the fast electrically detaching behavior (100% detaching efficiency...Design of rapidly detachable adhesives with high initial bonding strength is of great significance but it is full of great challenge. Here, we report the fast electrically detaching behavior (100% detaching efficiency in just 1 min under dozens of DC voltage) and high initial bonding strength (>12 MPa) of epoxy-based ionic conductive adhesives (ICAs). The epoxy-based ICAs are fabricated by introducing polyethylene glycol dimethyl ether (PEGDE) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]OTF) into epoxy. The combination of PEGDE and [EMIM]OTF enables the free ions to migrate directively in electric field, and the anchoring of PEG chains onto epoxy chains ensures the long-term reliability of ICAs. The investigation on the electrically detaching mechanism suggests that the enrichment and following rapid interfacial electrochemical reactions of [EMIM]OTF lead to formation of metal hydroxide (Me(OH)n) nanoparticles at the bonding interfaces, thus the strong interactions containing interlocked forces, van de Waals’ forces and hydrogen bonding interactions between ICAs and bonding substrates are destroyed. This work provides a promising direction for detachable adhesives with both high initial bonding strength and high detaching efficiency in short time.展开更多
Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low b...Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low bonding strength and intolerance to mold are major drawbacks,so that proper modification before use is essential.Glutaraldehyde is one of the more apt cross-linking agents for soybean protein adhesives,which can effectively improve the bonding strength and water resistance of the adhesive.Equally,glutaraldehyde is also an efficient and broad-spectrum fungicide that can significantly improve the anti-fungal properties of a soy protein adhesive.In the work presented here,matrix assisted laser desorption ionization(MALDI-ToF)mass spectrometry and Fourier transform infrared spectroscopy techniques were used to analyze the reaction mechanism of glutaraldehyde cross-linking soybean protein.The results confirmed the reaction of the aldehyde group with amino groups of the side chains and the amide groups of the peptide linkages constituting the skeletal chain of the protein.The laboratory plywood and particleboard bonded with glutaraldehyde-soy bean protein adhesives were prepared to determine the adhesive bonding properties,the dry strength,24 h cold water soaking wet strength and 3 h hot water(63°C)wet strength of plywood were 2.03,1.13 and 0.75 MPa,respectively,which satisfied the requirements of industrial production.展开更多
Anisotropic conductive adhesive technology for electronics packaging and interconnect application has significantly been developed during the last few years. It is time to make a summary of what has been done in this ...Anisotropic conductive adhesive technology for electronics packaging and interconnect application has significantly been developed during the last few years. It is time to make a summary of what has been done in this field. The present paper reviews the technology development, especially from the reliability point of view. It is pointed out that anisotropic conductive adhesives are now widely used in many applications and the reliability data and models have been developed to a large extent for anisotropic conductive adhesives in various applications.展开更多
Hot-melt (HM) adhesives offer advantages over their contemporary water-based and solvent-based adhesives like low volatile organic compounds (VOCs), 100% solid, fast drying, setting etc. In recent years, to reduce the...Hot-melt (HM) adhesives offer advantages over their contemporary water-based and solvent-based adhesives like low volatile organic compounds (VOCs), 100% solid, fast drying, setting etc. In recent years, to reduce their dependence on dwindling petroleum resources and due to the enormous use of HM adhesives in packaging areas that demand 100% recyclability, efforts have been devoted to making these formulations completely bio-based, sustainable and biodegradable. In this attempt, research and developments have been focused on using starch, modified starch, soy protein, polylactides, polyamides, lignin and vegetable oils as a partial/fully replacement to the petrochemical<span style="font-family:Verdana;">-<span style="font-family:Verdana;">based polymers. The huge amount of research going on in the field of bio-based polymers has still not reached its complete potential in the field of HM adhesives. In this review paper<span style="font-family:Verdana;">,<span style="font-family:Verdana;"> HM adhesives based on sustainable raw materials namely starch, modified starch, polyamides, poly (lactic acid), soy protein and lignin are discussed.展开更多
A selection of 22 low-melting polymers was thermally and rheologically evaluated to be used as hot-melt adhesives in mixed-substrate joining samples. The choice of polymers was based on the published melting point. It...A selection of 22 low-melting polymers was thermally and rheologically evaluated to be used as hot-melt adhesives in mixed-substrate joining samples. The choice of polymers was based on the published melting point. It was required to include a broad variety of different polymers backbones to study the influence of the different polymers comprehensively. A tool-box of widely applicable tests was developed to judge if a thermoplastic polymer is suitable for a hot-melt adhesive application. Melting temperature (onset, peak and offset temperature) and melting enthalpy were determined using standardized methods. Rheological methods were used to characterize the shear rate dependence and the flow behavior at the application temperature. The wetting behavior of the polymers was evaluated with contact angle measurements. The adhesive strength of the most promising candidates was analyzed using the Lumi Frac-adhesion method including the failure pattern.展开更多
文摘This review is composed of three main parts each of which is written by well-known top specialists that have been,in a way or other,also the main participants of the majority of the developments reported.Thus,after a general part covering the grand lines and more in-depth views of more recent tannin,lignin,carbohydrate and soy bioadhesives,somemix of the other bio raw materials with soy protein and soy flour and some other differently sourced bioadhesives for wood,this review presents a more in-depth part on starch-based wood adhesives and a more indepth part covering plant protein-based adhesives.It must be kept in mind that the review is focused on completely or almost completely biosourced adhesives,the fashionable adhesives derived from mixes of biosourced materials with synthetic resins having been intentionally excluded.This choice was made as the latter constitute only an intermediate interval,possibly temporary if even for a somewhat long times,towards a final full bioeconomy of scale in this field.This review also focuses on more recent results,mainly obtained in the last 10–20 years,thus on adhesive formulations really innovative and sometimes even non-traditional.In all these fields there is still a lot of possibility of innovation for relevant formulation as this field is still in rapid growth.
文摘Polymer science continues to play a transformative role in materials innovation,enabling breakthroughs across diverse domains including energy storage,flexible electronics,surface engineering,and soft robotics.At the heart of these advances lies a critical,often defining factor:the interface.Whether between polymers and solid substrates,liquids,gases,or other polymers,interfacial phenomena govern adhesion,wetting,energy dissipation,chemical reactivity,and signal transmission.Interfaces are not passive boundaries but active zones of complexity and function,where molecular interactions shape material performance at every scale—from nanometers to entire devices.
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supported by National Research Foundation of Korea(NRF)(RS-2024-00336766 and RS-2023-00301974)support of the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(RS-2023-00220748)。
文摘Since 2009,perovskite solar cells(PSCs)have advanced significantly,achieving over 26%efficiency for single-junction devices and exceeding 34%for silicon-perovskite tandem cells.Despite these successes,the weak adhesion of C_(60)to perovskite layers,due to van der Waals interactions,hinders long-term stability.In this study,we introduce electron-deficient intermolecular adhesives(EDIAs)as a novel interlayer material to enhance adhesion between perovskite and C_(60)layers.Comprehensive analyses,including density functional theory calculations,microscopy,and spectroscopy,demonstrate that EDIAs,particularly NDI-C9-Ace comprising of three key functionalities:aπ-electron-deficient arene core,a hydrophobic passivation core,and a secondary-bond anchoring core,significantly improve bonding strength and recombination passivation.This leads to enhanced efficiency as well as enhanced mechanical and photochemical stability in PSCs.Long-term stability tests further confirm the superior durability of EDIA-enhanced devices.This study highlights EDIA as a promising strategy for enhancing the robustness and efficiency of PSCs.
基金supported by the National Natural Science Foundation of China(Nos.22273098,22373003,22103002 and 52033001)the Key Project of Anhui Province Science and Technology Innovation Platform(No.202305a12020030)the financial support from the Anhui Provincial Natural Science Foundation(No.2408085Y004)。
文摘Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.
基金Project (51172088) supported by the National Natural Science Foundation of China
文摘Face centred cubic（FCC） TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives（ECAs） with the polymer matrix.Electrically conductive properties of the ceramic ECAs were studied.The bulk electrical resistivity varied with the powder content of the FCC-TiB in ECAs.The FCC-TiB filled ECAs also showed the percolation behavior that usually occurred for the metal-filled ECAs,the percolation threshold was located at the content of 60%FCC-TiB.A minimum value of 0.1 Ω·cm was obtained at a content of 75%FCC-TiB.In order to check the reliability of mechanical property,tensile test was done to measure the shear strength,and the shear strength dropped with increasing the content of FCC-TiB powders.It is about 12.26 MPa at the content of 70%TiB powders.The Cu filled ECAs were also prepared for comparison.The properties of the oxidation resistance of the two ECAs were evaluated.The results show that the ceramic ECAs have excellent oxidation resistance and better stability compared with the Cu filled ECAs.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)。
文摘The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.
基金supported by the Teaching Reform Key Research Project of Beijing Forestry University, China (No. BJFU2010JG014)
文摘We aim to present an overview of the status of adhesives in the wood industry, especially in the area of wood-based panels. The review summarizes the current state of research of two kinds of adhesives, i.e., synthetic adhesives and natural adhesives. Synthetic adhesives, consisting of urea-formaldehyde resins （UF）, phenol-formaldehyde resins （PF）, polyvinyl acetate emulsion （PVAc） and isocyanates, are widely used. For UF, most investigations are concerned with the reduction of free formaldehyde; for PF, most studies focus on finding new chemicals to replace phenol. PVAc has poor properties, but these can be improved by a blending reactions and copolymerization with other chemicals. Isocyanate is an environmentally friendly synthetic adhesive, but also suffers from inadequate properties. Natural adhesives, such as protein/starch, lignin and tannins, have poor bonding effect that limits their level of use, but their main advantages are that they are environmentally friendly and a renewable resource. Studies of modification can improve the bonding performances and gradually cause natural adhesives to become applied in industrial production. Some proposals for future development and the importance of environmentally friendly adhesives are provided, which will be helpful in future theoretical and experimental research.
基金the ERA-CoBioTech project WooBAdh(Environmentally-friendly bioadhesives from renewable resources)and by the Slovenian Ministry of Education.Science and Sport and the Slovenian Research Agency within the framework of the program P4-0015.
文摘The curing process of two biobased adhesives:pine tanninhexamine(TH)and organosolv lignin non-isocyanate polyurethane(NIPU),suitable for interior nonstructural use,were compared with commercial urea-formaldehyde(UF)adhesive.Changes in chemical structure before and after the curing process were observed with Fouriertransform infrared spectroscopy(FTIR).The process of adhesive curing was monitored with differential scanning calorimetry(DSC)and the automated bonding evaluation system(ABES).Both DSC and ABES measurements confirmed UF as the fastest and NIPU as the slowest curing adhesive observed.Taking into account the ABES results,the optimal pressing parameters for the TH adhesive would be 4 min at 175℃,for the NIPU adhesive 7 min at 200℃and for the UF 1.5 min at 100℃.Strong linear correlation was observed between mechanical and chemical curing for the UF and NIPU adhesives,whereas lower correlation was observed for the TH adhesive.At all observed adhesives,the DSC measurements were underestimating the curing process determined by ABES in the first part and overestimating it at the end.The underestimation was the most evident with the TH adhesive and the less with the UF adhesive.When comparing the uncured and cured FTIR spectra of all three types of adhesives,a drastic decrease in the characteristic band of-OH groups at 3330–3400 cm^(−1)and an increase in the signal intensity at 2920 cm^(−1)of aliphatic-CH2-groups were observed.For the UF adhesive,the C=O stretching frequency has shifted from 1632 cm^(−1)for uncured to three different bands at 1766,1701,and 1655 cm^(−1)for cured UF.The sharp band for phenolic alcohols at 1236 cm^(−1)of C–O stretch and hydroxyl O–H functional group at 1009 cm^(−1)and at 684 cm^(−1)of uncured TH adhesive diminished during curing,which indicates that a crosslinking reaction occurs via-OH groups.The peak of the C=O group of urethane bridges at 1697 cm^(−1)for uncured NIPU shifted to lower wavenumber at 1633 cm^(−1)for cured NIPU.
文摘Soy-protein isolate(SPI)was used to prepare non-isocyanate polyurethane(NIPU)thermosetting adhesives for wood panels by reacting it with dimethyl carbonate(DMC)and hexamethylene diamine.Both linear as well as branched oligomers were obtained and identified,indicating how such oligomer structures could further cross-link to form a hardened network.Unusual structures were observed,namely carbamic acid-derived urethane linkages coupled with lactam structures.The curing of the adhesive was followed by thermomechanical analysis(TMA).It appeared to follow a two stages process:First,at a lower temperature(maximum 130℃),the growth of linear oligomers occurred,finally forming a physically entangled network.This appeared to collapse and disentangle,causing a decrease of MOE,as the temperature increases.This appears to be due to the ever more marked Brownian movements of the linear oligomer chains with the increase of the temperature.Second,chemical cross-linking of the chains appeared to ensue,forming a hardened network.This was shown by the thermomechanical analysis(TMA)showing two distinct MOE maxima peaks,one around 130℃ and the other around 220℃,with a very marked MOE decrease between the two.Plywood panels were prepared and bonded with the SPI-NIPU wood adhesive and the results obtained are presented.The adhesive appeared to pass comfortably the requirements for dry strength of relevant standards,showing to be suitable for interior grade plywood panels.It did not pass the requirements for wet tests.However,addition of 15%of glycerol diglycidyl ether improved the wet tests results but still not enough to satisfy the standards requirements.
基金financially supported by the Special Funds of National Ministry of Finance for the Transformation of Industrial Technology Achievements (No.CJ2007-475)
文摘The electrochemical migration (ECM) behavior of the electrically conductive adhesives (ECAs) filled with pure Ag powder or Ag-plated Cu composite powder with varied Ag:Cu ratios was investigated under the condition of applying constant voltage and distilled water environment.ECM resistance was determined from the current-time curves.The microstructure and composition of ECM dendrite products were analyzed by SEM/EDS and XRD.It was found that the ECM resistance of Ag-plated Cu composite powder-filled ECAs was evidently higher than that of pure Ag powder-filled ECAs.The Ag:Cu ratio of composite powder in ECAs had notable influence on ECM resistance,which was enhanced with the decrease of Ag:Cu ratios.The composition of dendrites formed between cathode and anode during ECM process was not uniform for Ag-plated Cu-filled ECAs.An ECM inhibiting mechanism of Ag-plated Cu composite powder was proposed according to analysis of the electrochemical impedance spectroscopy,Tafel plot and dendrite composition.
基金Project was supported by the Natural Science Foundation of Guangdong Province(No.2019A1515011844)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(ZHD201801 and 31512050201).
文摘This study has been conducted to evaluate the application of silver nanoparticles(NPs)in Electrically Conductive Adhesives(ECAs),filled with hybrid silver flakes and NPs,and silver flakes as a control sample,at a filler loading of 78 wt.%,83 wt.%and 88 wt.%and cured at 150℃and 180℃,respectively.The results show that the electrical and thermal conductivities of ECAs were improved with the increasing of filler loading and curing temperature.Adding silver NPs in silver flakes negatively affected the electrical and thermal conductivities of ECAs at a low filler mass fraction of 78 wt.%,because the segregation of NPs enlarged the average distance of silver flakes;while it positively influenced the electrical and thermal conductivities of ECAs at a loading ratio of 88 wt.%,probably due to NPs filling in the gaps between silver flakes or even sintering together with each other or with silver flakes,especially when curing at high temperature of 180℃.
基金Projects(51605220,U1637101)supported by the National Natural Science Foundation of ChinaProject(BK20160793)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject(NS2020029)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Inspired by the microstructure of gecko’s toe,two kinds of polyvinyl chloride(PVC)gels with different modulus were poured on a silicon mold with micropillars,and then a bio-inspired adhesive with variable modulus was manufactured in this study.The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested,respectively,on a smooth glass and a printed circuit board(PCB)with different surface structures.The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bioinspired adhesives.The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2−5 times,and due to the use of variable modulus of PVC gel,the surface micropillars can maintain high aspect ratio and flexible tips at the same time.Moreover,the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation.An adhesion-desorption device was made according to the movement of the gecko toes,and the PCB was successfully grasped.
文摘Increasing global energy crisis and scarcity of petroleum resources has shifted focus of chemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as petroleum and natural gas [1] [2], would be gradually replaced by renewable biopolymers. Starch is a relatively inexpensive and renewable product from abundant plants, easy processing and it has been extensively used as binders, sizing materials, glues and pastes [3], but its bonding capacity is not strong enough to glue wood [4]. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of starch-based adhesives. In starch-based wood adhesive many new approaches have come forward for effective use it in wood/wood composite adhesive giving comparable performance as synthetic adhesives. This review of starch-based adhesives is made with the focus on starch modification methods for improving properties of starch-based adhesives.
基金supported by the National Natural Science Foundation of China (No. 52103097)the Doctor Foundation of Southwest University of Science and Technology (No. 20zx7144)+3 种基金the Special Foundation for Young Scientists of Sichuan Province (No. 71112541)the Guangdong Natural Science Foundation (No. 2021A1515010675)the Key Project of Guangzhou Science and Technology Plan Project (No. 201904020034)the Guangdong Project of R&D Plan in Key Areas (No. 2020B010180001).
文摘Design of rapidly detachable adhesives with high initial bonding strength is of great significance but it is full of great challenge. Here, we report the fast electrically detaching behavior (100% detaching efficiency in just 1 min under dozens of DC voltage) and high initial bonding strength (>12 MPa) of epoxy-based ionic conductive adhesives (ICAs). The epoxy-based ICAs are fabricated by introducing polyethylene glycol dimethyl ether (PEGDE) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]OTF) into epoxy. The combination of PEGDE and [EMIM]OTF enables the free ions to migrate directively in electric field, and the anchoring of PEG chains onto epoxy chains ensures the long-term reliability of ICAs. The investigation on the electrically detaching mechanism suggests that the enrichment and following rapid interfacial electrochemical reactions of [EMIM]OTF lead to formation of metal hydroxide (Me(OH)n) nanoparticles at the bonding interfaces, thus the strong interactions containing interlocked forces, van de Waals’ forces and hydrogen bonding interactions between ICAs and bonding substrates are destroyed. This work provides a promising direction for detachable adhesives with both high initial bonding strength and high detaching efficiency in short time.
基金supported by the National Natural Science Foundation of China(31660176)the Yunnan Provincial Natural Science Foundation(202201AU070222)and Scientific Research Fund Project of Yunnan Provincial Department of Education(2022J0490)+1 种基金financed by the ERA-CoBioTech Project WooBAdh(Environmentally-friendly bioadhesives from renewable resources)by the Slovenian Ministry of Education.Science and Sport and the Slovenian Research Agency within the Framework of the Program P4-0015.
文摘Soy protein adhesives are currently a hot research topic in the wood panels industry for the abundant raw material reserves,reasonable price and outstanding environmental features.But their poor water resistance,low bonding strength and intolerance to mold are major drawbacks,so that proper modification before use is essential.Glutaraldehyde is one of the more apt cross-linking agents for soybean protein adhesives,which can effectively improve the bonding strength and water resistance of the adhesive.Equally,glutaraldehyde is also an efficient and broad-spectrum fungicide that can significantly improve the anti-fungal properties of a soy protein adhesive.In the work presented here,matrix assisted laser desorption ionization(MALDI-ToF)mass spectrometry and Fourier transform infrared spectroscopy techniques were used to analyze the reaction mechanism of glutaraldehyde cross-linking soybean protein.The results confirmed the reaction of the aldehyde group with amino groups of the side chains and the amide groups of the peptide linkages constituting the skeletal chain of the protein.The laboratory plywood and particleboard bonded with glutaraldehyde-soy bean protein adhesives were prepared to determine the adhesive bonding properties,the dry strength,24 h cold water soaking wet strength and 3 h hot water(63°C)wet strength of plywood were 2.03,1.13 and 0.75 MPa,respectively,which satisfied the requirements of industrial production.
文摘Anisotropic conductive adhesive technology for electronics packaging and interconnect application has significantly been developed during the last few years. It is time to make a summary of what has been done in this field. The present paper reviews the technology development, especially from the reliability point of view. It is pointed out that anisotropic conductive adhesives are now widely used in many applications and the reliability data and models have been developed to a large extent for anisotropic conductive adhesives in various applications.
文摘Hot-melt (HM) adhesives offer advantages over their contemporary water-based and solvent-based adhesives like low volatile organic compounds (VOCs), 100% solid, fast drying, setting etc. In recent years, to reduce their dependence on dwindling petroleum resources and due to the enormous use of HM adhesives in packaging areas that demand 100% recyclability, efforts have been devoted to making these formulations completely bio-based, sustainable and biodegradable. In this attempt, research and developments have been focused on using starch, modified starch, soy protein, polylactides, polyamides, lignin and vegetable oils as a partial/fully replacement to the petrochemical<span style="font-family:Verdana;">-<span style="font-family:Verdana;">based polymers. The huge amount of research going on in the field of bio-based polymers has still not reached its complete potential in the field of HM adhesives. In this review paper<span style="font-family:Verdana;">,<span style="font-family:Verdana;"> HM adhesives based on sustainable raw materials namely starch, modified starch, polyamides, poly (lactic acid), soy protein and lignin are discussed.
文摘A selection of 22 low-melting polymers was thermally and rheologically evaluated to be used as hot-melt adhesives in mixed-substrate joining samples. The choice of polymers was based on the published melting point. It was required to include a broad variety of different polymers backbones to study the influence of the different polymers comprehensively. A tool-box of widely applicable tests was developed to judge if a thermoplastic polymer is suitable for a hot-melt adhesive application. Melting temperature (onset, peak and offset temperature) and melting enthalpy were determined using standardized methods. Rheological methods were used to characterize the shear rate dependence and the flow behavior at the application temperature. The wetting behavior of the polymers was evaluated with contact angle measurements. The adhesive strength of the most promising candidates was analyzed using the Lumi Frac-adhesion method including the failure pattern.
