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  • Open Access

    ARTICLE

    Self-Cross-Linked Tannin-Aminated Tannin Surface Coatings for Particleboard

    Bengang Zhang1,*, Antonio Pizzi2,*, Mathieu Petrissans1, Anelie Petrissans1, Colin Baptiste1

    Journal of Renewable Materials, Vol.11, No.12, pp. 4097-4121, 2023, DOI:10.32604/jrm.2023.029761

    Abstract Aminated tannins were prepared by reacting mimosa condensed tannin extract with ammonia yielding the substitution of many, if not all of the tannin hydroxyl groups with –NH2 groups. A tannin-aminated tannin (ATT) particleboard coating was then prepared by reacting raw tannin extract with aminated tannin extract and thus cross-liking the two by substituting tannin’s hydroxyl groups with the –NH2 groups on the aminated tannin to form –NH-bridges between the two. The resulting particleboard coating gave encouraging results when pressed at 180°C for 3 min. Conversely, the system in which tannin was reacted/cross-liked with urea (ATU) by a similar amination reaction… More >

  • Open Access

    ARTICLE

    A Melamine–Dialdehyde Starch Wood Particleboard Surface Finish without Formaldehyde

    Bengang Zhang1,*, Antonio Pizzi2,*, Mathieu Petrissans1, Anelie Petrissans1, Baptiste Colin1

    Journal of Renewable Materials, Vol.11, No.11, pp. 3867-3889, 2023, DOI:10.32604/jrm.2023.028888

    Abstract Melamine-dialdehyde starch resins used for wood surface finishes have been developed. The reaction of melamine with dialdehyde starch has been shown to occur by FTIR and MALDI ToF spectrometry, with several oligomer species due to the reaction of the two materials being identified, and the resin thermal stability was studied by thermogravimetric analysis. The resins were prepared by two different procedures when it was realized that dialdehyde starch is sensitive to too high a temperature for prolonged times. The melamine-dialdehyde starch resins were applied on particleboard supports as a direct liquid surface finish and a resin-impregnated paper. The surface finishes… More >

  • Open Access

    ARTICLE

    Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams

    Elham Azadeh1, Antonio Pizzi1,2,*, Christine Gerardin-Charbonnier1,*, Philippe Gerardin1

    Journal of Renewable Materials, Vol.11, No.6, pp. 2823-2848, 2023, DOI:10.32604/jrm.2023.027651

    Abstract Non-isocyanate polyurethane (NIPU) foams from a commercial hydrolysable tannin extract, chestnut wood tannin extract, have been prepared to determine what chemical species and products are taking part in the reactions involved. This method is based on two main steps: the reaction with dimethyl carbonate and the formation of urethane bonds by further reaction of the carbonated tannin with a diamine-like hexamethylene diamine. The hydroxyl groups on the tannin polyphenols and on the carbohydrates intimately linked with it and part of a hydrolysable tannin are the groups involved in these reactions. The carbohydrate skeleton of the hydrolysable tannin is also able… More > Graphic Abstract

    Hydrolysable Chestnut Tannin Extract Chemical Complexity in Its  Reactions for Non-Isocyanate Polyurethanes (NIPU) Foams

  • Open Access

    ARTICLE

    MALDI ToF Investigation of the Reaction of Soy Protein Isolate with Glutaraldehyde for Wood Adhesives

    Qianyu Zhang1,2, Antonio Pizzi3, Hong Lei1,2,*, Xuedong Xi1,2,*, Ming Cao1,2, Long Cao1,2

    Journal of Renewable Materials, Vol.11, No.3, pp. 1439-1450, 2023, DOI:10.32604/jrm.2022.023535

    Abstract 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… More > Graphic Abstract

    MALDI ToF Investigation of the Reaction of Soy Protein Isolate with Glutaraldehyde for Wood Adhesives

  • Open Access

    ARTICLE

    MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

    Claudio Del Menezzi1,2,3, Antonio Pizzi2,*, Siham Amirou2, Xuedong Xi4,5

    Journal of Renewable Materials, Vol.11, No.2, pp. 539-553, 2023, DOI:10.32604/jrm.2022.024971

    Abstract

    This article presents the first applied results of using citric acid in combinations with a melamine-urea-formaldehyde (MUF) resin for bonding wood veneers. The chemical reactions involved are shown based on a MALDI ToF analysis of the reaction of the MUF resin with citric acid. The preliminary results of the physical and mechanical properties of the LVL prepared are also presented. Veneers from Populus sp were used to manufacture 5-layer laminated veneer lumber (LVL) of small dimensions. Five combinations of the amount of citric acid, MUF spread rate and pressing parameters were tested. LVL bonded with 20% of citric acid +… More > Graphic Abstract

    MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

  • Open Access

    ARTICLE

    Matrix-Assisted Laser Desorption-Ionization Time of Flight (MALDI-TOF) Mass Spectrometry of Phenol-FormaldehydeChestnut Tannin Resins

    M.C. Lagel1,*, A. Pizzi1,2, S. Giovando3

    Journal of Renewable Materials, Vol.2, No.3, pp. 207-219, 2014, DOI:10.7569/JRM.2014.634111

    Abstract Natural hydrolysable chestnut tannin extracts used to partially substitute phenol in Phenol-Formaldehyde (PF) resins for phenolic rigid foams were analysed by matrix-assisted desorption ionization time of fl ight (MALDI-TOF) mass spectrometry. PF only, chestnut only and PF-chestnut copolymerised oligomer types and distribution were determined. MALDI-TOF analyses of a PF control resin (with the same molar ratio) and of chestnut tannin extracts were performed in order to identify the peaks of molecular weights corresponding to copolymers of chestnut tannins with phenol and formaldehyde. More >

  • Open Access

    ARTICLE

    MALDI-ToF Analysis of Tannin-Resorcinol Resins by Alternative Aldehydes: Glyoxal and Glutaraldehyde

    A. Sauget1,*, X. Zhou1, A. Pizzi1,2

    Journal of Renewable Materials, Vol.2, No.3, pp. 186-200, 2014, DOI:10.7569/JRM.2013.634138

    Abstract Glyoxal and glutaraldehyde are two viable alternatives to formaldehyde for the preparation of tanninresorcinol-aldehyde adhesive but lead to less resistant glue joint. Tannin-resorcinol-glyoxal (TRG1) and tannin-resorcinol-glutaraldehyde (TRG2) resins have been prepared and analyzed by matrix-assisted laser desorption/ionization time of fl ight (MALDI-ToF) spectrometry to understand the chemical process behind the pre-curing of these resins and possibly the causes of this lower resistance. The analysis showed that TRG resins are not a simple mix of resorcinol-aldehydes oligomers and fl avonoids, but a much more complex combination of various species including tannin-aldehydes and tannin-resorcinol oligomers. More >

  • Open Access

    ARTICLE

    Experimental Investigation of Two-Phase Flow Maldistribution in Plate Heat Exchangers

    Zhaiyk Tokhtarov1,*, Vitaly Perov2, Vitaly Borisov3, Evgeny Tikhomirov4, Olga Grunina5, Nadezhda Kapustina5,6, Elmira Cherkasova7, Natalya Suray5

    FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.4, pp. 1015-1024, 2022, DOI:10.32604/fdmp.2022.019534

    Abstract After conducting a critical survey of the different categories of existing heat exchangers, the results of several experiments about the behaviour of a two-phase current in an open channel are reported. The results confirm the complexity of the problems induced in heat exchangers by flow maldistribution, especially when two-phase flows are considered in multi-channel systems. It is shown that severe misalignment of heat exchangers can lead to a loss of economic performance of more than 25%. Improper distribution of fluid flow causes longer fluid coils to form, and the liquid cochlea can eventually occupy a large space, thereby reducing heat… More >

  • Open Access

    ARTICLE

    Covalent and Ionic Bonding between Tannin and Collagen in Leather Making and Shrinking: A MALDI-ToF Study

    Antonio Pizzi*

    Journal of Renewable Materials, Vol.9, No.8, pp. 1345-1364, 2021, DOI:10.32604/jrm.2021.015663

    Abstract Collagen powder hydrolysates were reacted with a solution of commercial mimosa bark tannin extract. The mixture was prepared at ambient temperature and prepared at 80°C to determine what reactions, if any, did occur between the collagen protein through its amino acids and the polyphenolic condensed tannin. The reaction products obtained were analyzed by matrix assisted laser desorption ionization time-of-flight (MALDI ToF) mass spectrometry. Reactions between the two materials did appear to occur, with the formation of a relatively small proportion of covalent and ionic linkages at ambient temperature but a considerable proportion of covalent linkages tannin-protein amino acids and the… More >

  • Open Access

    ARTICLE

    Soy Protein Isolate Non-Isocyanates Polyurethanes (NIPU) Wood Adhesives

    Xinyi Chen1,2, Antonio Pizzi1,*, Xuedong Xi1,2, Xiaojian Zhou2, Emmanuel Fredon1, Christine Gerardin3

    Journal of Renewable Materials, Vol.9, No.6, pp. 1045-1057, 2021, DOI:10.32604/jrm.2021.015066

    Abstract 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°C), the growth of linear oligomers occurred, finally forming a physically entangled network.… More >

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