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1.
Chromatographic Analysis of the Reaction of Soy Flour with Formaldehyde and Phenol for Wood Adhesives 总被引:2,自引:0,他引:2
Linda Lorenz Charles R. Frihart James M. Wescott 《Journal of the American Oil Chemists' Society》2007,84(8):769-776
The desire to make more biobased and lower-cost bonded wood products has led to an interest in replacing some phenol and formaldehyde
in wood adhesives with soybean flour. Improved knowledge of the soy protein properties is needed to relate resin chemistry
to resin performance before and after wood bonding. To expose the soy protein’s functional groups, it needs to be disrupted,
with minimal hydrolysis, to maximize its incorporation into the final polymerized adhesive lattice. The best conditions for
alkali soy protein disruption were to maintain the temperature below 100 °C and react the soy flour with sodium hydroxide
at pH 9–12 for about 1 hour. A gel permeation chromatography procedure was optimized to determine conditions for selectively
breaking down the high molecular weight soy protein fragments that contribute to high adhesive viscosity. This method and
extraction data were used to evaluate the reaction of the disrupted soy flour protein with formaldehyde and phenol to provide
a stable adhesive. The results were used to develop more economical adhesives that are ideally suited for the face section
of oriented strandboard. 相似文献
2.
大豆7S与11S球蛋白尿素变性后的粘接性质研究 总被引:2,自引:0,他引:2
随着人们对环境保护意识的增加和地球有限资源的缺乏,大豆蛋白在胶粘剂工业中的应用也越来越显示出强大的吸引力,鉴于前人的研究成果,文章研究了大豆7S和11S球蛋白经过尿素变性后在松木、樱桃木和胡桃木上的粘接强度和湿润能力。结果表明在不同的木块上不同胶粘剂有不同的粘接强度和湿润性能。7S大豆蛋白尿素变性后在硬木上有较好的湿润性。1M尿素变性赋予11S蛋白的粘接强度最高,3M尿素变性后,7S蛋白在硬木上的粘接强度大于11S蛋白。蛋白质的二级结构测量表明β-折叠对于3 M尿素变性后的大豆蛋白在硬木上的粘接强度起着重要作用,而无规则卷曲是降低1 M尿素变性7S大豆蛋白粘接强度的主要因素。 相似文献
3.
Xin Li Donghai Wang Jo A. Ratto 《Journal of Adhesion Science and Technology》2013,27(18-19):2065-2074
Making thin-layered fiberboard and recycling the fiberboard materials are two major approaches to save quantities of wood fiber in fiberboard manufacture, which offer both environmental and economic benefits to the society and industry. The objective of this research was to develop high-strength, thin-layered pulp fiberboards (TLPBs) using sodium dodecyl sulfate (SDS)-modified soy protein adhesives for packaging applications. SDS-modified soy protein adhesives demonstrated significantly higher bonding strength than did unmodified soy protein adhesive. Results showed that the TLPB with SDS-modified soy flour adhesive (0.05?g/cm2 area density and 0.6?mm of thickness) had stronger tensile strength, similar burst index, and similar or better water soaking properties in comparison to commercial solid fiberboard (1.24?g/cm2 area density and 1.7?mm thickness). 相似文献
4.
Charles R. Frihart Holly Satori 《Journal of Adhesion Science and Technology》2013,27(18-19):2043-2052
Soy flour adhesives using polyamidoamine-epichlorohydrin (PAE) resin as the curing agent are being used commercially to make bonded wood products. The original studies on the soy-PAE adhesives used purified soy protein isolate, but the much lower cost soy flour is now used commercially. We examined the performance of commercially available soy flours that have their proteins either mainly in their native (90 protein dispersibility index (PDI)) or denatured (70 and 20 PDI) states. We expected that the more native state soy proteins with their better dispersibility would provide better adhesion to wood surfaces and enhanced reaction with PAE resin. Small-scale wood bonding tests showed that neither of these effects was observed without and with a low level of PAE. In these tests, the solids content of the soy formulations had a large influence on adhesive viscosity but little influence on bond strength. Additionally, little difference was observed in any of the adhesive or viscosity properties between the soy flours having either a 0.152 or 0.075?mm (100 or 200 mesh) particle size. 相似文献
5.
Seung Woo Choi Dong Wan Seo Young Don Lim Young Gi Jeong M. S. Islam Mollah Heon Park Tae Whan Hong Whan Gi Kim 《应用聚合物科学杂志》2011,121(2):764-769
The reactive multihydroxy soybean oil (MHSBO) was synthesized from epoxidized soybean oil (ESBO). The ESBO was reacted with ethylene glycol to obtain MHSBO having high functionality. This study investigated a feasibility to prepare wood adhesive through the reaction of polymeric methylene‐diphenyl‐4,4′‐diisocyanate (pMDI) with MHSBO. Different polyurethane adhesives were prepared with a variety of equivalent mole ratios (eq. mole ratios) of MHSBO to pMDI. The chemical reactions of adhesives were analyzed using 1H NMR and Fourier transform infrared (FTIR), and their thermal studies were investigated by DSC and TGA. The MHSBO/pMDI resins (3 : 1 and 2 : 1 eq. mole ratios) showed endothermic peaks, whereas the MHSBO/pMDI resins (1 : 2 and 1 : 3 eq. mole ratios) showed exothermic peaks. The best adhesion strength was found when plywood was bonded with the adhesive of a eq. mole ratio of 2 : 1 (MHSBO : pMDI). These results indicated that the bond strength was not related to the reactivity obtained from the FTIR spectra. But it was explained that the adhesion strength increased as the residual NCO groups in the adhesive reacted with the hydroxy groups of wood during the manufacturing of plywood. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
6.
Urea-formaldehyde (UF) resin is one of the most commonly used wood adhesives for making particleboards. However, UF emits carcinogenic formaldehyde and is derived from nonrenewable petrochemicals. In this study, a new formaldehyde-free wood adhesive that is based on soy flour and a renewable material-based curing agent (CA) were prepared and evaluated for the preparation of M-2 grade particleboards. The new CA was derived from ammonia and epichlorohydrin that can be derived from renewable glycerol. The composition of the adhesive was soy flour/sodium hydroxide/CA at a dry weight ratio of 9/0.3/1.0. The modulus of rupture, modulus of elasticity, and internal bond strength met the minimum industrial requirements of M-2 particleboards using the following variables: hot-press temperature of 190?°C, hot-press time of 240?s, the adhesive usage of the face particles of 12?wt.%, the adhesive usage of the core particles of 10?wt.%, and the target particleboard density of 0.80?g/cm3. 相似文献
7.
Xiaohua KongGuoguang Liu Jonathan M. Curtis 《International Journal of Adhesion and Adhesives》2011,31(6):559-564
A novel bio-based poly (ether ester) polyol containing both primary and secondary functional groups was synthesized from canola oil using a low cost and efficient procedure. In this work, use of the new canola oil derived polyol for the production of polyurethane (PU) adhesives was demonstrated. The canola oil based PU adhesives had similar or better adhesive properties in terms of lap shear strength than three commercial PU adhesives. The effect of NCO/OH ratio and temperature on adhesive characteristics on wood bonding was also evaluated by lap shear tests. It was found that the use of an elevated curing temperature (i.e. 100 °C), as well as optimized NCO/OH molar ratio (higher than 1.5/1.0), improved the wood adhesive properties. The overall chemical resistance of bio-based PU adhesives to cold water, acid and alkali was comparable to that of commercial PU adhesives whilst its resistance to hot water was superior. 相似文献
8.
Jane L. O’Dell Charles R. Frihart 《Journal of Adhesion Science and Technology》2013,27(18-19):2027-2042
We studied the high temperature performance of soy meal processed to different protein concentrations (flour, concentrate, and isolate), as well as formulated soy-based adhesives, and commercial nonsoy adhesives for comparison. No thermal transitions were seen in phenol-resorcinol-formaldehyde (PRF) or soy-phenol-formaldehyde (SoyPF) or in as-received soy flour adhesive during differential scanning calorimetry scans heating at 10?°C/min between 35 and 235?°C. Heat flow rates decreased in the order soy flour (as received)?>?SoyPF?>?PRF?>?emulsion polymer isocyanate (EPI). In thermogravimetric analysis (TGA) scans from 110 to 300?°C at 2?°C/min, total weight loss decreased in the order soy flour (as-received)>SoyPF?>?PRF?>?casein?>?maple?>?EPI. For bio-based materials, the total weight loss (TGA) decreased in the order soy flour (as-received) > concentrate, casein?>?isolate. Dynamic mechanical analysis from 35 to 235?°C at 5?°C/min of two veneers bonded by cured adhesive showed 30–40% decline in storage modulus for maple compared to 45–55% for the adhesive made from soy flour in water (Soy Flour) and 70–80% for a commercial poly(vinyl acetate) modified for heat resistance. DMA on glass fiber mats showed thermal softening temperatures increasing in the order Soy Flour?<?casein?<?isolate?<?concentrate. We suggest that the low molecular weight carbohydrates plasticize the flour product. When soy-based adhesives were tested in real bondlines in DMA and creep tests in shear, they showed less decrease in storage modulus than the glass fiber-supported specimens. This suggests that interaction with the wood substrate improved the heat resistance property of the adhesive. Average hot shear strengths (ASTM D7247) were 4.6 and 3.1?MPa for SoyPF and Soy Flour compared to 4.7 and 0.8?MPa for PRF and EPI and 4.7 for solid maple. As a whole, these data suggest that despite indications of heat sensitivity when tested neat, soy-based adhesives are likely to pass the heat resistance criterion required for structural adhesives. 相似文献
9.
Soy and cottonseed proteins appear promising as sustainable and environment-friendly wood adhesives. Because of their higher cost relative to formaldehyde-based adhesives, improvement in the adhesive performance of proteins is needed. In this work, we evaluated the adhesive properties of soy and cottonseed protein formulations that included phosphorus-containing acids and esters. For cottonseed protein isolate, most of these additives improved dry adhesive strength, with methylphosphonic acid, phosphorous acid, and phosphoric acid increasing the dry strength by 47, 44, and 42%, respectively, at their optimal concentrations. For soy protein isolate, these additives did not show significant benefits. The phosphorus-containing additives also improved the hot water resistance of the cottonseed protein formulations but showed either no effect or a negative effect for the of soy protein formulations. Thus, the combination of cottonseed protein with phosphorus additives appears to be attractive as wood adhesives. 相似文献
10.
H. N. Cheng Catrina Ford Michael K. Dowd Zhongqi He 《Journal of Adhesion Science and Technology》2013,27(24):2657-2666
Most commercial wood adhesive use either formaldehyde-based resins or polyurethanes, both of which include potentially toxic chemicals in their formulations. As a result, proteins are being considered as greener and more sustainable wood adhesives. While most of the protein adhesive studies focus on soy proteins, there is also interest in exploring alternatives. In this work, testing of the adhesive performance of cottonseed protein isolate was undertaken in the presence of protein denaturants, i.e. guanidine hydrochloride (GuHCl), sodium dodecyl sulfonate (SDS), urea, and alkali. For comparison, soy protein isolate was also included in the study. At optimal dosage levels, the dry adhesive strength of cottonseed protein isolate could be enhanced by 38, 25, or 47% with SDS, GuHCl, or urea, respectively. The dry adhesive strength and hot water resistance of cottonseed protein isolate was generally superior to that of soy protein isolate, with or without the denaturants. Thus, the combination of cottonseed protein with an optimal concentration of a denaturant may be a potentially promising polymeric system for use as wood adhesives. 相似文献
11.
12.
Ang Khoon Poh Cheng Sit Foon Chuah Cheng Hock 《Journal of Adhesion Science and Technology》2013,27(11):1020-1033
Polyurethane (PU) adhesives for wood bonding were prepared from palm oil-based polyester polyol in a solventless condition that reduces the risk of volatile organic compounds to human health and the environment. The polyester polyol was synthesized from epoxidized palm olein prior to reacting with polymeric 4,4′-methylene diphenyl diisocyanate (pMDI) and toluene 2,4-diisocyanate (TDI) to produce wood-bonding PU adhesives. The effect of glycerol cross-linker, dibutyltin dilaurate catalyst and NCO/OH ratio on lap shear strength and pot life of the PU adhesives were studied. The green strength of the PU adhesives was achieved on day 4 for TDI-based adhesives and day 5 for pMDI-based adhesives. The newly formulated PU adhesives have superior chemical resistance in cold water, hot water, acidic medium and alkaline medium by only showing light deterioration (2–8%) in lap shear strength. The PU adhesives prepared from pMDI exhibited higher lap shear strength and thermal stability as compared to adhesives prepared from TDI adduct. Both adhesives have improved mechanical performance (two folds higher in lap shear strength) as compared to commercial wood bonding adhesives. 相似文献
13.
Xiaoqun Mo & Xiuzhi Susan Sun 《Journal of Adhesion Science and Technology》2013,27(18-19):2014-2026
Soybean proteins have great potential as bio-based adhesives. The objectives of our study were to develop and characterize formaldehyde-free soybean wood adhesives with improved water resistance. Second-order response surface regression models were used to determine the effects of soy protein isolate concentration, sodium chloride, and pH on adhesive performance. All three variables affected both dry and wet strengths of bonded wood specimens. The optimum operation zone for preparing adhesives with improved water resistance is at a protein concentration of 28% and pH 5.5. Sodium chloride had negative effects on adhesive performance. Soy adhesives modified with 0.5% sodium chloride had dry strength, wet strength, and boiling strength of bonded specimens comparable to nonmodified soy adhesives. Rheological study indicated that soy adhesives exhibited shear thinning behavior. Adhesives modified with sodium chloride showed significantly lower viscosity and yield stress. Sodium chloride-modified soy adhesives formed small aggregates and had low storage moduli, suggesting reduced protein–protein interactions. These formaldehyde-free soy adhesives showed strong potential as alternatives to commercial formaldehyde-based wood adhesives. 相似文献
14.
Christopher G. Hunt Linda F. Lorenz Carl J. Houtman Eder Valle Thomas Coolidge Chera Mock Charles R. Frihart 《Journal of the American Oil Chemists' Society》2023,100(1):69-79
The impact of jet cooking on shear strength of soy-and-water adhesives was investigated to understand the higher shear strength of commercial soy protein isolates compared to soy flours. Soy flour-based wood adhesives are appealing because of their bio-based content, low formaldehyde emission, and low cost, but their commercial application is limited by low wet cohesive strength. Previous researchers proposed that the process of jet cooking (steam injection with high turbulence followed by rapid cooling) was responsible for the high (~3 MPa) wet shear strength of adhesives made with commercially produced soy protein isolate, using the ASTM D 7998 test. In this work, we show that jet cooking did dramatically increase the wet strength of laboratory-produced, native-state soy protein isolate from 0.6 to 3 MPa, a strength similar to many commercial isolates. Jet cooking was far less effective at developing wet strength of soy flours, but greatly increased the viscosity of virtually all our soy materials. We hypothesize that the benefits of jet cooking are primarily a result of nonequilibrium protein aggregation states because subsequent wet autoclaving of jet cooked soy proteins dramatically decreased wet strength. The dramatic differences in adhesive properties between commercial soy protein isolates and soy flours suggests that the common practice of using results obtained with commercial isolates to predict the performance of soy flour adhesives is inappropriate. 相似文献
15.
Many of the currently used wood adhesives contain chemicals that are harmful to human health and the environment. Increasing environmental and human health concerns have made the development of safe biobased adhesives a priority. In this study, two plant proteins, i.e., zein and wheat gluten, were used to develop wood adhesives and their performance was compared through simple lap shear tests and plywood flexural/internal bond tests in dry and wet conditions. To increase their bond strength, cellulose nanofibers were added to create nanocomposite adhesives and glutaraldehyde was also used to crosslink the proteins. Single-lap shear test was performed to measure the bond strength of different adhesive formulations and determine the optimal formulations and processing conditions. Fractured bond surfaces were studied using optical observation and scanning electron microscopy to determine bond failure mechanisms. Thermal and chemical properties of the adhesives were evaluated using thermogravimetric analysis and Fourier transform infrared spectroscopy, respectively. The bond strength of both zein and gluten adhesives was significantly increased by the addition of the cellulose nanofibers and/or glutaraldehyde, although the two adhesives responded differently to the two reinforcement materials due to the different solvents used to prepare the adhesives. The bond failure mode changed from cohesive failure of the adhesive to structural failure of the adherent for the gluten adhesive containing CNFs and glutaraldehyde. Potential zein and gluten adhesive formulations were used to produce plywood samples and their performance was assessed under different conditions. The formulations with industrial potential were discovered through this study. 相似文献
16.
Recent adhesive technologies have focused on the development of high-quality and eco-friendly adhesives. Thus, there is a gradual shift from the currently used chemical-based adhesives toward harmless adhesives with improved quality and performance. Here, we evaluated the potential use of bacteria-produced recombinant mussel adhesive protein (MAP) as a harmless wood furniture adhesive. We formulated a MAP wood adhesive as an inclusion body type for economical preparation, and we confirmed its harmlessness through the non-detection of volatile organic compounds and heavy metals. The formulated MAP showed sufficiently strong bulk adhesive strength for the dried gluing of wood adherends. We also found that the formulated MAP wood adhesive exhibits robust adhesion in various environmental conditions, including open assembly times, incubation times, temperatures, and humidity levels. In summary, the developed recombinant MAP could be successfully used as a promising environmentally-friendly, harmless wood furniture adhesive. 相似文献
17.
Y. Liu 《The Journal of Adhesion》2013,89(6):593-605
Petrochemical-based adhesives such as urea-formaldehyde and phenol-formaldehyde resins are predominant wood adhesives. In this study, a new wood adhesive from lignin was developed and characterized. The new adhesive consisted of demethylated kraft lignin (DKL), a byproduct in the production of dimethyl sulfoxide from kraft lignin, and a polyethylenimine (PEI). Lap-shear specimens bonded with this new DKL-PEI adhesive system had very high shear strength and were very water-resistant. The effects of the preparation time, the curing conditions, the total solids content of the adhesive, the DKL/PEI weight ratio and the molecular weight of PEI on the shear strength and water-resistance of the resulting lap-shear specimens were studied in detail. Investigation on the curing chemistry of this new adhesive revealed that phenolic hydroxyl groups were oxidized to form quinones that further reacted with PEI. It was proposed that the curing mechanisms of this DKL-PEI adhesive were similar to the quinone-tanning processes in nature. 相似文献
18.
Petrochemical-based adhesives such as urea-formaldehyde and phenol-formaldehyde resins are predominant wood adhesives. In this study, a new wood adhesive from lignin was developed and characterized. The new adhesive consisted of demethylated kraft lignin (DKL), a byproduct in the production of dimethyl sulfoxide from kraft lignin, and a polyethylenimine (PEI). Lap-shear specimens bonded with this new DKL-PEI adhesive system had very high shear strength and were very water-resistant. The effects of the preparation time, the curing conditions, the total solids content of the adhesive, the DKL/PEI weight ratio and the molecular weight of PEI on the shear strength and water-resistance of the resulting lap-shear specimens were studied in detail. Investigation on the curing chemistry of this new adhesive revealed that phenolic hydroxyl groups were oxidized to form quinones that further reacted with PEI. It was proposed that the curing mechanisms of this DKL-PEI adhesive were similar to the quinone-tanning processes in nature. 相似文献
19.
Soy-oil-based waterborne polyurethane (WPU) is used to improve wet strength in shear test of wood bonded with an adhesive of soy protein isolate (SPI) by dispersing WPU into SPI slurry. WPU׳s effects on the physiochemical properties of WPU-SPI adhesives are characterized through Fourier transform infrared spectrum, transmission electron microscopy, thermal analysis, contact angle, and mechanical strength. Wet strength of the WPU-SPI adhesives increases by 65% compared to SPI control. Moreover, the microstructure of WPU has effects on the interactions between WPU and SPI. In this study, smaller and more uniform distributed WPU0002 is easier to interact and form stronger crosslinking network with protein than WPU0500. The stronger interaction between WPU0002 and protein results in increased viscosity and bond strength. The WPU-SPI blended adhesives show significantly improved wet strength, demonstrating their potential as wood adhesives. 相似文献
20.
Doroteja Vnučec Andreja Kutnar Andreja Goršek 《Journal of Adhesion Science and Technology》2013,27(8):910-931
Over recent years, the interest in bio-adhesives, including soy-based adhesives, has increased rapidly. Among natural renewable resources suitable for industrial use, soy is a reasonable choice due to its high production volume and the small use of soy meal-based products for human food consumption. Soy flour can be an ideal raw material for the manufacturing of wood adhesives due to its low cost, high protein content and easy processing. There are also more concentrated forms of soy proteins, i.e. concentrates and isolates, which are also suitable raw materials for adhesive production except that their prices are higher. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of soy-based adhesives. However, there is insufficient experimental data available for understanding the influences of modification methods on the structure of soy proteins and therefore for understanding the influences of structural changes on the adhesion. In this paper, some experimental techniques are proposed to be used for analysing soy-based adhesives to enable better understanding of those factors and improve future development. This review of soy-based adhesives is made with the focus on soy proteins’ chemical composition, soy protein product types (raw materials for adhesive production), modification methods for improving the adhesive properties of soy-based adhesives, and commercial soy-based adhesives. 相似文献