Mimosa Tannin Research Articles

Mechanical characterization of industrial particleboard panels glued with cornstarch–mimosa tannin–urea formaldehyde resins

The aim of this work was to validate the utility and performance of optimal laboratory cornstarch–mimosa tannin-based resins in the industrial particleboard production. In this way, the cornstarch and mimosa tannin was introduced in the classic adhesive formulation in order to supply a part of urea-formaldehyde (UF). Our results show that industrial particleboard panels (8.2 m × 1.85 m × 19 mm) bonded with optimal cornstarch–mimosa tannin–UF (10:4:86; mass ratio) resins exhibited comparable mechanical properties to those of boards bonded with commercial UF resins and largely satisfied the exigencies of European norms EN 312. The formaldehyde emission levels obtained from panels bonded with cornstarch–mimosa tannin–UF were lower to those obtained from panels bonded with control UF. Finally, the addition of cornstarch and mimosa tannin improves markedly the water resistance of UF resins.

Impregnation of Scots pine and beech with tannin solutions: effect of viscosity and wood anatomy in wood infiltration.

The impregnation process of Scots pine and beech samples with tannin solutions was investigated. The two materials involved in the process (impregnation solution and wood samples) are studied in depth. Viscosity of mimosa tannin solutions and the anatomical aspect of beech and Scots pine were analysed and correlated. The viscosity of tannin solutions presents a non-newtonian behaviour when its pH level increases, and in the case of addition of hexamine as a hardener, the crosslinking of the flavonoids turns out to be of great importance. During the impregnation of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.), the liquid and solid uptakes were monitored while taking into consideration the different conditions of the impregnation process. This method allowed to identify the best conditions needed in order to get a successful preservative uptake for each wooden substrate. The penetration mechanism within the wood of both species was revealed with the aid of a microscopic analysis. Scots pine is impregnated through the tracheids in the longitudinal direction and through parenchyma rays in the radial direction, whereas in beech, the penetration occurs almost completely through longitudinal vessels.

Corn flour-mimosa tannin-based adhesives without formaldehyde for interior particleboard production

A formaldehyde-free adhesive consisting of a corn flour/NaOH adhesive mixture and a mimosa tannin/hexamine intermediate component was developed and evaluated for application to wood panels such as particleboards. The main ingredients of this adhesive include corn flour, NaOH, mimosa tannin and hexamine. This study investigated the physical properties (rheological and thermal analysis) of corn flour/NaOH and mimosa tannin/hexamine adhesives as well as mechanical properties of particleboards produced with these adhesives. Thermomechanical (TMA) experiments indicate the best performance of the adhesives to be around the relative mass proportions of 50:50 between corn flour/NaOH and mimosa tannin/hexamine. Former NMR measurements on corn starch and mimosa tannin proved that the two components behave as a polymer blend rather than co-reacting. The laboratory results show that particleboards bonded with the adhesive at this optimal ratio show good mechanical properties. Moreover, the formaldehyde emission levels obtained from boards bonded with the optimal adhesive were considerably lower to those obtained from boards made with control urea formaldehyde.

Reaction of condensed tannins with ammonia

Reaction of condensed (flavonoid) mimosa tannin extracts with concentrated aqueous ammonia has been investigated. For that purpose, catechin was also used as a flavonoid model compound and treated in similar conditions. Solid state CP-MAS 13C NMR and MALDI-ToF spectroscopy studies revealed that, unlike what was recently theorised, amination is not always regioselective and leading to the conversion of one single OH group in C4′ into NH2. In the present study, new reactions have been evidenced, clearly leading to multiamination of several phenolic hydroxyl groups, heterocycle opening, and oligomerisation and cross-linking through the formation of N bridges between flavonoid units.

Mimosa tannin resins for impregnated paper overlays

The surface quality of plywood coated with resin impregnated papers based on tannin/furfuryl alcohol resins was studied. Several hardeners such as hexamine, paraformaldehyde, formurea and a mixture of formurea and paraformaldehyde were added in small quantities to a mimosa tannin/furfuryl alcohol resin. Papers impregnated with resin based on tannin + furfuryl alcohol + paraformaldehyde, or + formurea were found to yield excellent results in standard water vapour resistance and cross-cut tests. Matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry and cross-polarisation-magic angle spinning NMR (CP-MAS 13C NMR) were used to show coreaction of tannin with furfuryl alcohol and even furfuryl alcohol self condensation under alkaline conditions, as well as coreaction of formaldehyde-yielding compounds such as hexamine with both tannin aromatic rings and the aromatic ring of furfuryl alcohol. Some of the more important oligomers formed were identified by MALDI-TOF.

Effects of plant tannin supplementation on animal responses and in vivo ruminal bacterial populations associated with bloat in heifers grazing wheat forage

<h2>ABSTRACT</h2> Two experiments were conducted to 1) enumerate the effect of tannin supplementation on ADG, bloat frequency, in vitro gas, and biofilm and foam production, and 2) quantify the influence of tannin supplementation on ruminal bacterial populations of heifers grazing wheat forage. Twenty-six heifers (286 ± 26 kg) were randomly allocated to 1 of 3 treatments that included a control (nontannin group) and 2 types of tannins (mimosa and chestnut tannins). Plant tannins (1.5% of DMI) were supplemented once daily mixed with a textured feed (500 g/animal). Heifers were visually monitored daily for bloat score (0 = no bloat, 3=severe bloat). In Exp. 1, supplementation of tannins reduced the rate of frothy foam and biofilm production with chestnut being more efficacious than mimosa tannins. There was no treatment × time interaction (P > 0.1) for ADG and bloat measurement. Chestnut tannin supplementation increased ADG (P < 0.05) with time (P < 0.01). Mean bloat score and bloat day were greater (P < 0.01) for the control diet than for tannin-supplemented treatment groups. In Exp. 2, Fibrobacter succinogenes, Streptococcus bovis, and Prevotella ruminicola strains were relatively stable with time (d 0, 10, and 25) in the rumen of animals not receiving tannin supplementation. However, with supplementation of chestnut and mimosa tannins, populations of P. ruminicola and strains of both F. succinogenes and Ruminococcus flavefaciens were increased, respectively. Results show that daily supplementing mimosa and chestnut tannins to heifers grazing wheat forage improved beef production and minimized bloat frequency with minimum impact to the microbial populations studied.

Low Formaldehyde Emitting Biobased Wood Adhesives Manufactured from Mixtures of Tannin and Glyoxylated Lignin

Kraft (LN-T-CO2-2) and wheat straw (CIMV) glyoxalated lignin mixed with mimosa tannin and hexamine as a hardener were used as wood adhesive resins in particleboard fabrication. The adhesive systems proportion used were 40/60 and 50/50 w/w for lignin and tannin, respectively. The gel time test was determined by knowing the polymerization time between the different mixes under the controlled conditions. The results showed a slower polymerization with the kraft lignin/mimosa tannin blending than with the wheat straw lignin/mimosa tannin one. Thermomechanical analyses (TMA) tests were carried out as an indication of the final strength of the adhesive systems revealed by the elasticity modulus (MOE). The MOE results have demonstrated the best mechanical resistance values in 40/60 lignin/mimosa tannin proportion with respectively 3.422 and 3.347 (MPa), for CIMV and LN-T-CO2-2, and 2.122 (MPa) for 50/50 proportion. Particleboards were prepared and the internal bond (IB) tests were carried out according to the European Standard EN 312. The IB tests confirmed the TMA results. The higher mechanical results of the IB were .43 and 0.53 (MPa), for CIMV and LN-T-CO2-2 lignin in a 40/60 lignin/mimosa tannin proportion. They were classified as interior panel P2 in according with the standard request EN-312. Free-formaldehyde was determined through the flask method EN 717-3. Particleboards prepared with these natural adhesive resins registered emissions at least 87 and 75% lower than the commercial UF and MUF dhesive resins. The panels were classified as E0.

Effect of catechins and tannins on depleted uranium-induced DNA strand breaks

The effects of polyphenols on plasmid DNA strand breaks by depleted uranium were studied using four catechins: (+)-catechin, (−)-epicatechin, (−)-epigallocatechin (EGC), and (−)-epigallocatechin gallate (EGCG); seven tannins: Chinese gallotannin, persimmon tannin (PST), mimosa tannin (MMT), myrobalan tannin, quebracho tannin, gambir tannin, and chestnut tannin; and gallic acid. The plasmid DNA strand breaks by uranyl ion (UO22+) with hydrogen peroxide (H2O2) were strongly enhanced by EGC, EGCG, MMT, and PST (condenced tannins). The obtained results showed that the DNA strand breaks are caused by UO22+ through the direct interaction between the uranyl complex and the negatively charged DNA phosphate backbone. The additional DNA strand breaks by the addition of polyphenols occurred through an indirect process by the reduction of UO22+ to UO2+ and hydroxyl radical formation through a Fenton-type reaction with H2O2.

Immobilization of vegetable tannins on tannery chrome shavings and their use for the removal of hexavalent chromium from contaminated water

Chestnut (C) and mimosa (M) tannins immobilized on chrome shavings (CS) as an adsorbent have been proposed to be an efficient and economical alternative in hexavalent chromium removal from aqueous solutions. The adsorption of hexavalent chromium onto chrome shavings-tannin (CS-T) adsorbents was performed using batch equilibrium technique at 25 ± 2 °C. The effect of pH is highly important especially in the case of high concentrations of hexavalent chromium. The maximum chromium uptake was obtained at pH 4. Two hours of contact time are enough to reach equilibrium. Sorption of chromium on CS-T was found to follow a pseudo-second order kinetic model (with correlation coefficients greater than 0.999). The adsorption equilibrium data fitted the Langmuir model well. The maximum adsorption capacity, of dry immobilized tannin adsorbent with 11.6% polyphenol, reached 42 mg Cr/g and 38 mg Cr/g in the case of chestnut and mimosa tannins, respectively.

Chemical composition of rumen microbial fraction and fermentation parameters as affected by tannins and saponins using an in vitro rumen fermentation system

Castro-Montoya, J. M., Makkar, H. P. S. and Becker, K. 2011. Chemical composition of rumen microbial fraction and fermentation parameters as affected by tannins and saponins using an in vitro rumen fermentation system. Can. J. Anim. Sci. 91: 433–448. Post-rumen chemical composition of the microbial fraction is one of the factors that determines the nutrients absorbed and available for maintenance and production of the animal. The hypothesis was that tannins and saponins alter chemical composition of rumen microbes and fermentation parameters in the rumen. Purified quebracho, mimosa, chestnut and sumach tannins; and quillaja and gypsophilla saponins were incubated with 380 mg of substrate (hay:concentrate 70:30 wt/wt) for 24 h in an in vitro gas production system at concentrations from 0.25 to 1.25 mg mL−1. Saponins increased N and reduced sugar contents of the liquid-associated microbes. The ratio of crude protein to purine bases significantly increased on adding sumach and chestnut tannins and decreased on the addition of quebracho and mimosa tannins. Quebracho, mimosa and chestnut tannins reduced total short-chain fatty acid production. The acetate:propionate ratio decreased for all additives. Results suggest that in vitro (a) depending on the source and the concentration, tannins would have an effect on the nitrogen and sugar contents of the liquid associated microbes, (b) saponins are likely to increase N and reduce sugar contents of rumen liquid associated microbes, and (c) estimation of microbial protein synthesis based on purine bases may lead to under- or over-estimations in the presence of tannins and saponins. In vivo studies are required to validate these results.

Starch-sugar synergy in wood adhesion science: basic studies and particleboard production

Synergic properties between starch and sugar were discovered. 100% crop-based starch and sugar formulations were studied. Classical preliminary tests such as curing temperature and gel time were measured for different starch-sucrose water suspensions. More significant information was deducted with applied tests such as plywood gluing tests and particleboard production. Wood-to-wood bonding properties were analysed applying NaOH and high temperature (180°C) as catalysts for starch gelification. Comparable strength to commercial urea-formaldehyde and polyvinyl acetate adhesives was achieved in plywood tests. Consequently, the knowledge acquired in wood bonding of flat surfaces was applied to particleboard production. These derived particleboards showed that it is possible to obtain a panel with only carbohydrates as gluing agent. Starch-sugar synergy in alkaline environment increases the internal bond (IB) of the natural panels up to 0.25 N/mm2. Possible mechanisms of synergy between these saccharides were proposed. Finally, a blended formulation with Mimosa tannin allows for achieving an internal bond of 0.40 N/mm2, which is the required value for interior grade particleboards (DIN EN 312). Starch-sugar-tannin adhesives are 100% environmentally-friendly formulations.

The use of tannin to prepare carbon gels. Part II. Carbon cryogels

Organic and derived carbon cryogels were prepared by sol–gel polycondensation of resorcinol (R) and formaldehyde (F) in the presence of mimosa tannin (T). We show that 2/3 in weight of the resorcinol can advantageously be replaced by tannin, and that resultant TRF organic gels can be freeze-dried and pyrolysed. The resultant low-cost carbon gels present similar pore textures than those of their expensive aerogel counterparts prepared from pure RF resin. However, the presence of tannin allows additional features that are encountered in a much lower extent in RF carbon gels. These materials can indeed be prepared from a much broader range of pHs (2–8), leading to pore-size distributions that are progressively shifted towards narrower pores when the pH increases. Such drastic change of porosity at fixed composition has never been reported so far. At pH 8, the carbons are poorly porous, whereas surface areas close to 650 m 2 g −1 are found at low and moderate pHs.

Extraction, Characterization and Utilization of Organosolv Miscanthus Lignin for the Conception of Environmentally Friendly Mixed Tannin/Lignin Wood Resins

Lignin was extracted from Miscanthus × giganteus using two procedures: an aqueous-ethanol organosolv treatment and a two-step process involving a dilute acid pre-soaking step followed by an aqueous-ethanol organosolv treatment. The organosolv lignin was subjected to a comprehensive structural characterization by 13C and MALDI-TOF MS and used for the formulation of a green wood adhesive prepared with 100% natural resins. The best formulation was composed of 60% of mimosa tannin and 40% of glyoxalated lignin extracted using a 1-step organosolv treatment. This formulation, when applied to wooden test panels yielded good internal bond strength results, which was good enough to pass relevant international standard specifications for interior-grade panels.

Shear Refinement of Formaldehyde-Free Corn Starch and Mimosa Tannin (Acacia mearnsii) Wood Adhesives

The aim of this work was to reduce the viscosity of formaldehyde-free corn starch–mimosa tannin wood adhesives, without adversely affecting the mechanical properties of the product. The reduction of viscosity was achieved using shear refinement. The study focused on the physical phenomena before cross-linking of the wood adhesive. The physical (rheological characterization) and mechanical (bond strength) properties of formaldehyde-free corn starch and mimosa tannin wood adhesives were measured. The results showed that the shear refinement (290 rpm and 5 min, optimal conditions) reduced the viscosity of the corn starch–mimosa tannin wood adhesives (from 100 000 to 458 Pa s) with the advantage of being stable over time. Mechanical tests showed that the shear refinement did not influence the mechanical properties of corn starch–mimosa tannin wood adhesives.

Cornstarch–mimosa tannin–urea formaldehyde resins as adhesives in the particleboard production

AbstractThe objective of this work was to demonstrate the utilisation of cornstarch–mimosa tannin‐based resins designed for application as an adhesive in particleboard production. Bond qualities of cornstarch–mimosa tannin–urea formaldehyde (UF) resins and commercial UF resin were assessed by using an automatic bonding evaluation system, prior to production of particleboards panels. In order to evaluate the quality of cornstarch–mimosa tannin–UF resins, particleboards were produced and physical and mechanical properties were investigated. These physical properties included rheological, thermogravimetric analysis and solid phase 13C NMR analysis of resins. Internal bond, surface soundness, thickness swelling, porosity, modulus of rupture and modulus of elasticity mechanical properties of particleboards bonded with cornstarch–mimosa tannin–UF resins were also determined.The results showed that it is possible to add cornstarch and mimosa tannin, respectively, up to 10 and 4% to the UF resin without to alter the physical and mechanical properties of the boards. The performance of these panels is comparable to those of boards made using commercial UF resin. Petrochemical UF resins could be partially substituted in industrial applications by addition of cornstarch and mimosa tannin extracts.

Derivatives of biomacromolecules as stabilizers of aqueous alumina suspensions

AbstractThe stabilization of alumina suspensions is key to the development of high‐performance materials for the ceramic industry, which has motivated extensive research into synthetic polymers used as stabilizers. In this study, mimosa tannin extract and a chitosan derivative, that is, macromolecules obtained from renewable resources, are shown to be promising to replace synthetic polymers, yielding less viscous suspensions with smaller particles and greater fluidity, that is, more homogeneous suspensions that may lead to better‐quality products. The functional groups of tannin present in mimosa extract and N,N,N‐trimethylchitosan (TMC) are capable of establishing interactions with the alumina surface, thus leading to repulsion between the particles mainly due to steric and electrosteric mechanisms, respectively. The stabilization of the suspension induced by either TMC or mimosa tannin was confirmed by a considerable decrease in viscosity and average particle size, in comparison with alumina suspensions without stabilizing agents. The viscosity/average particle size decreased by 49/84% and 52/87% for suspensions with TMC and mimosa tannin, respectively. In addition, the increase in the absolute zeta potential upon addition of either TMC or mimosa tannin extract, especially at high pHs, points to an increased stability of the suspension. The feasibility of using derivatives of macromolecules from renewable sources to stabilize aqueous alumina suspensions was therefore demonstrated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Chestnut and mimosa tannin silages: Effects in sheep differ for apparent digestibility, nitrogen utilisation and losses

This paper reports effects of chestnut and mimosa tannins on N utilisation in sheep. Tannins were added to grass either at ensilage or incorporated into grass silage at feeding. The study used an 8 × 5 incomplete Latin Square design with eight mature wether sheep and five 21-day periods. Tannin additions reduced in vivo apparent digestibilities of dry matter (DM), organic matter (OM) and neutral detergent fibre (aNDFom) compared with the untreated control silage ( P<0.001). Reductions ranged from 7.6% for DM to 8.5% for aNDFom. Chestnut compared to mimosa tannin silages produced higher values for DM intake (734 g/day versus 625 g/day) and in vivo digestibility for DM, OM and aNDFom (0.66, 0.68 and 0.69 versus 0.61, 0.63 and 0.62; P<0.001). A substantial shift occurred in the pattern of N excretion in sheep fed the tannin versus control silages. As a proportion of daily N intake, urinary N losses were lower (56.4 g/100 g N versus 65.1 g/100 g N intake) and faecal N losses were higher (40.2 g/100 g N versus 29.8 g/100 g N intake) for sheep fed the tannin silages compared with those fed the control grass silage ( P<0.001). Nitrogen intake was higher in sheep fed the chestnut compared to mimosa tannin silages (16.2 g/day versus 13.4 g/day; P<0.001), reflecting the lower DM intake of sheep fed the mimosa silages. However, faecal N loss was lower for chestnut compared to mimosa tannin silage fed sheep (38.2 g/100 g N versus 42.1 g/100 g N intake; P<0.01), resulting in higher N retentions with the chestnut compared to the mimosa silage fed sheep (5.49 g/100 g N versus 1.38 g/100 g N intake). Faecal N losses were also higher when tannins were added during ensiling rather than at feeding ( P<0.05). Although there was no overall effect of tannins on N retention in mature wether sheep, it is likely that productive ruminants with higher protein requirements would retain more N from silages containing chestnut tannins. Tannins added externally to grass silages may generate some benefits on N utilisation and environmental N excretions in sheep fed the silages.

Characterization of Acacia mangium polyflavonoid tannins by MALDI-TOF mass spectrometry and CP-MAS 13C NMR

The MALDI-TOF mass spectrometry (MS) and solid state CP-MAS 13C Nuclear Magnetic Resonance (NMR) spectroscopic technique were introduced to characterize Acacia mangium tannin (condensed tannins). The MALDI-TOF MS illustrated a series of peaks corresponding to oligomers of condensed tannins of up to 11 flavonoid units (3200 Da). A. mangium condensed tannins were found to consist predominantly of prorobinetinidin combined with profisetinidin and prodelphinidin. Both the MALDI-TOF mass spectra and the solid state CP-MAS 13C NMR indicated that the A. mangium tannins obtained from Kudat, had an almost completely linear structure; In addition, Lembah Beringin, consist of “angular” polymer structure; and Tawau, has included “twice-angular” polymer structures present in oligomers type of up to 7 flavonoid units. The high degree of polymerization of linear, angular type, twice-angular structures and longer oligomer (3200 Da) chains have not been observed in previous studies of condensed tannins. The spectra also indicated that A. mangium tannins are more heavily branched and have higher degree of polymerization (>7.0) compared to commercial mimosa (A. mearnsii) tannin (4.9). Because tannins are phenolic, it was expected that they can be used to replace phenol–formaldehyde (PF) adhesives.

FRIENDLY WOOD PRESERVATIVE SYSTEM BASED ON POLYMERIZED TANNIN RESIN-BORIC ACID FOR OUTDOOR APPLICATIONS

Boron compounds are used as wood preservatives as they are both fungicide and insecticide, relatively inexpensive and environmentally acceptable. Nevertheless, in the field of wood protection, borates are only used for indoor non-exposed applications or in association with other biocides, due to their main disadvantage of being readily leachable from treated wood. To overcome this problem, boric acid was fixed into wood with condensed tannins and hexamine through a non-formaldehyde emission polymer network. Treated mixtures were tested with different proportions of mimosa tannins and hexamine, with and without co-added boric acid. The treated beech samples were leached and tested according to European Standard EN 113 against Pycnoporus sanguineus in tropical conditions. The systems had minimal boron depletion and good fungal decay efficacy, meeting the efficacy requirements of EN 113.

High resin content natural matrix–natural fibre biocomposites

Composites of good performance formed from non-woven mats of flax and hemp fibres and natural resin matrices have been prepared. Both higher density thin composites as well as lower density thicker composites have been prepared. Two natural matrices types were used: (i) commercial mimosa flavonoid tannin extract with 5% hexamine added as hardener and (ii) a mix of mimosa tannin + hexamine with glyoxalated organosolv lignin of low molecular weight, these two resins mixed 50/50 by solids content weight. The composites prepared were tested for MOE in bending and in tension and for maximum breaking strength in tension. Some of the mats were corona treated and the optimum length of corona treatment determined to improve the composites MOEs and breaking strength. These were related to the morphology of the treated fibre. Thermomechanical analysis (TMA), Brinell surface hardness and contact angle tests were also carried out with good results. The composites made with the mix of tannin and lignin resins as a matrix remained thermoplastic after a first pressing. The flat sheets prepared after the first pressing were then thermoformed into the shape wanted.