The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

Hervé Cheradame - One of the best experts on this subject based on the ideXlab platform.

  • chemical and physicochemical investigation of an aminoalkylalkoxysilane as strengthening agent for Cellulosic Materials
    Biomacromolecules, 2011
    Co-Authors: Zied Souguir, Anne-laurence Dupont, Bertrand Lavédrine, Jeanbaptiste Despinose De Lacaillerie, Hervé Cheradame
    Abstract:

    AMDES (aminopropylmethyldiethoxysilane) was used to investigate the physicochemical and chemical events related to the introduction of aminoalkylalkoxysilanes in Cellulosic Materials. Using 29Si CP-MAS and 1H NMR to study the reactivity and structural modification of AMDES in the paper it was shown that polymerization occurs in situ. The distribution of the active compound on the surface of the fibers and throughout the fibers’ thickness was visualized by SEM-EDS. A relation between moisture content, fiber swelling, and uptake of AMDES was found. To better represent old and brittle documents, the paper was predegraded by oxidation with sodium hypochlorite. XRD confirmed the advanced destruction of the amorphous areas of cellulose. Adding AMDES in the oxidized paper resulted in improved mechanical properties, a roughly unmodified degree of polymerization of cellulose, but a slight increase in the yellowing, probably due to several possible reaction products such as imines, amine, amides, and Maillard react...

  • Chemical and Physicochemical Investigation of an Aminoalkylalkoxysilane As Strengthening Agent for Cellulosic Materials
    Biomacromolecules, 2011
    Co-Authors: Zied Souguir, Anne-laurence Dupont, Jean-baptiste D 'espinose De Lacaillerie, Bertrand Lavédrine, Hervé Cheradame
    Abstract:

    AMDES (aminopropylmethyldiethoxysilane) was used to investigate the physicochemical and chemical events related to the introduction of aminoalkylalkoxysilanes in Cellulosic Materials. Using 29Si CP-MAS and 1H NMR to study the reactivity and structural modification of AMDES in the paper it was shown that polymerization occurs in situ. The distribution of the active compound on the surface of the fibers and throughout the fibers’ thickness was visualized by SEM-EDS. A relation between moisture content, fiber swelling, and uptake of AMDES was found. To better represent old and brittle documents, the paper was predegraded by oxidation with sodium hypochlorite. XRD confirmed the advanced destruction of the amorphous areas of cellulose. Adding AMDES in the oxidized paper resulted in improved mechanical properties, a roughly unmodified degree of polymerization of cellulose, but a slight increase in the yellowing, probably due to several possible reaction products such as imines, amine, amides, and Maillard reactions products. The deacidification efficacy was established and the strengthening effect was shown to arise from the interaction of AMDES with the cellulose fibers.

Gunnar Westman - One of the best experts on this subject based on the ideXlab platform.

  • Nano-Cellulosic Materials: the impact of water on their dissolution in DMAc/LiCl.
    Carbohydrate polymers, 2013
    Co-Authors: Merima Hasani, Ute Henniges, Alexander Idström, Lars Nordstierna, Gunnar Westman, Thomas Rosenau, Antje Potthast
    Abstract:

    The dissolution behaviour of disassociated Cellulosic Materials in N,N-dimethylacetamide/lithium chloride (DMAc/LiCl) was investigated. The parameters monitored were chromatographic elution profiles and recovered mass by means of gel permeation chromatography (GPC) with RI detection. In order to elucidate the impact of the disassembly on Cellulosic fibres, comparative studies were performed with the non-disassociated cellulose counterparts. The importance of the presence of water was addressed by Karl Fischer titration and solvent exchange experiments. Morphological changes during the dissolution process were studied by scanning electron microscopy (SEM). Dissolution of fibrillated Cellulosic Materials is impeded compared to the non-fibrillated material. This is a consequence of the high-surface-area fibrils prone to retain high amounts of water. Dissolution behaviour of nano-crystalline Cellulosic Materials appeared to be source-dependent. Due to the absence of entangled networks, these Materials retain only water bound at the surface of the nano-crystallites, indicative of both the exposed surface area and solubility. The small cellulose nano-particles extracted from dissolving pulp show lower solubility compared to the large NCC particles from cotton.

  • Regioselective cationization of Cellulosic Materials using an efficient solvent-minimizing spray-technique
    Cellulose, 2012
    Co-Authors: Hanna Motte, Gunnar Westman
    Abstract:

    Cationization of different Cellulosic Materials was successfully accomplished using an efficient solvent-minimizing spray-technique. The obtained Materials were studied and evaluated in regard to reaction efficiency and regioselectivity using 1D and ^1H–^13C correlated 2D NMR experiments. The high consistencies and temperatures applied using the spray-technique resulted in reagent effective etherifications and shorter reaction times. The NMR spectra indicated that the spray-technique favors substitutions at position O-6, showing a regioselectivity of O-6 > O-2 > O-3 for softwood kraft pulp (SKP) and cotton linters. However, cationization of mercerized cellulose and dissolving pulp, using the spray-technique, demonstrated more efficient reactions compared to SKP and cotton, and a regioselectivity of O-6 ≥ O-2 > O-3. Nanocrystalline cellulose showed the lowest reactivity and a regioselectivity of O-6 ≫ O-2 > O-3. In this work we provide information on structure–property relationships and characterization methods for modified polysaccharides, together with a solvent system that is well known industrially and in line with sustainability aspects.

Dusan Losic - One of the best experts on this subject based on the ideXlab platform.

  • graphene borate as an efficient fire retardant for Cellulosic Materials with multiple and synergetic modes of action
    ACS Applied Materials & Interfaces, 2017
    Co-Authors: J Nine, Diana N. H. Tran, Tran Thanh Tung, Shervin Kabiri, Dusan Losic
    Abstract:

    To address high fire risks of flamable Cellulosic Materials, that can trigger easy combustion, flame propagation, and release of toxic gases, we report a new fire-retardant approach using synergetic actions combining unique properties of reduced graphene oxide (rGO) and hydrated-sodium metaborates (SMB). The single-step treatment of Cellulosic Materials by a composite suspension of rGO/SMB was developed to create a barrier layer on sawdust surface providing highly effective fire retardant protection with multiple modes of action. These performances are designed considering synergy between properties of hydrated-SMB crystals working as chemical heat-sink to slow down the thermal degradation of the Cellulosic particles and gas impermeable rGO layers that prevents access of oxygen and the release of toxic volatiles. The rGO outer layer also creates a thermal and physical barrier by donating carbon between the flame and unburnt wood particles. The fire-retardant performance of developed graphene-borate compos...

  • Graphene-Borate as an Efficient Fire Retardant for Cellulosic Materials with Multiple and Synergetic Modes of Action
    2017
    Co-Authors: Md J. Nine, Diana N. H. Tran, Tran Thanh Tung, Shervin Kabiri, Dusan Losic
    Abstract:

    To address high fire risks of flamable Cellulosic Materials, that can trigger easy combustion, flame propagation, and release of toxic gases, we report a new fire-retardant approach using synergetic actions combining unique properties of reduced graphene oxide (rGO) and hydrated-sodium metaborates (SMB). The single-step treatment of Cellulosic Materials by a composite suspension of rGO/SMB was developed to create a barrier layer on sawdust surface providing highly effective fire retardant protection with multiple modes of action. These performances are designed considering synergy between properties of hydrated-SMB crystals working as chemical heat-sink to slow down the thermal degradation of the Cellulosic particles and gas impermeable rGO layers that prevents access of oxygen and the release of toxic volatiles. The rGO outer layer also creates a thermal and physical barrier by donating carbon between the flame and unburnt wood particles. The fire-retardant performance of developed graphene-borate composite and mechanism of fire protection are demonstrated by testing of different forms of Cellulosic Materials such as pine sawdust, particle-board, and fiber-based structures. Results revealed their outstanding self-extinguishing behavior with significant resistance to release of toxic and flammable volatiles suggesting rGO/SMB to be suitable alternative to the conventional toxic halogenated flame-retardant Materials

Zied Souguir - One of the best experts on this subject based on the ideXlab platform.

  • chemical and physicochemical investigation of an aminoalkylalkoxysilane as strengthening agent for Cellulosic Materials
    Biomacromolecules, 2011
    Co-Authors: Zied Souguir, Anne-laurence Dupont, Bertrand Lavédrine, Jeanbaptiste Despinose De Lacaillerie, Hervé Cheradame
    Abstract:

    AMDES (aminopropylmethyldiethoxysilane) was used to investigate the physicochemical and chemical events related to the introduction of aminoalkylalkoxysilanes in Cellulosic Materials. Using 29Si CP-MAS and 1H NMR to study the reactivity and structural modification of AMDES in the paper it was shown that polymerization occurs in situ. The distribution of the active compound on the surface of the fibers and throughout the fibers’ thickness was visualized by SEM-EDS. A relation between moisture content, fiber swelling, and uptake of AMDES was found. To better represent old and brittle documents, the paper was predegraded by oxidation with sodium hypochlorite. XRD confirmed the advanced destruction of the amorphous areas of cellulose. Adding AMDES in the oxidized paper resulted in improved mechanical properties, a roughly unmodified degree of polymerization of cellulose, but a slight increase in the yellowing, probably due to several possible reaction products such as imines, amine, amides, and Maillard react...

  • Chemical and Physicochemical Investigation of an Aminoalkylalkoxysilane As Strengthening Agent for Cellulosic Materials
    Biomacromolecules, 2011
    Co-Authors: Zied Souguir, Anne-laurence Dupont, Jean-baptiste D 'espinose De Lacaillerie, Bertrand Lavédrine, Hervé Cheradame
    Abstract:

    AMDES (aminopropylmethyldiethoxysilane) was used to investigate the physicochemical and chemical events related to the introduction of aminoalkylalkoxysilanes in Cellulosic Materials. Using 29Si CP-MAS and 1H NMR to study the reactivity and structural modification of AMDES in the paper it was shown that polymerization occurs in situ. The distribution of the active compound on the surface of the fibers and throughout the fibers’ thickness was visualized by SEM-EDS. A relation between moisture content, fiber swelling, and uptake of AMDES was found. To better represent old and brittle documents, the paper was predegraded by oxidation with sodium hypochlorite. XRD confirmed the advanced destruction of the amorphous areas of cellulose. Adding AMDES in the oxidized paper resulted in improved mechanical properties, a roughly unmodified degree of polymerization of cellulose, but a slight increase in the yellowing, probably due to several possible reaction products such as imines, amine, amides, and Maillard reactions products. The deacidification efficacy was established and the strengthening effect was shown to arise from the interaction of AMDES with the cellulose fibers.

Jinping Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Fabrication of hydrophobic Cellulosic Materials via gas–solid silylation reaction for oil/water separation
    Cellulose, 2019
    Co-Authors: Zeming Zhang, Hongding Tang, Jinping Zhou
    Abstract:

    Development of a simple, green, and universal method for the fabrication of hydrophobic Cellulosic Materials is of significance for enlarging their applications. Herein, one-step gas–solid reaction for the preparation of hydrophobic Cellulosic Materials having any shape and size is proposed. The substance can be made hydrophobic, as it is fully exposed to the reactive organosilane vapor. Filter paper (FP), a typical Cellulosic material, was selected to study the hydrophobic modification with perfluorooctyltriethoxysilane (PFTS). The results indicated that PFTS was successfully introduced onto the surface of the cellulose fiber. Compared with the pristine FP, the physicochemical properties of the PFTS-modified FP (SFP) were significantly improved. The silane content of SFP was approximately 45–55 mg g−1, and the water contact angle was as large as 146° ± 3° under the proper conditions. SFP retained good chemical stability in harsh conditions of acidic, alkaline and saline solutions that is appropriate in practical environment. It was successfully applied in separating a series of oil/water mixtures with a separation efficiency of over 99%. The flux and separation efficiency remained high even after 30 reuse cycles (99% for chloroform/water mixtures). Moreover, the proposed vapor-based technique has the potential to allow continuous preparation of hydrophobic Cellulosic Materials with industrial applications. Organosilane vapor-based surface modification is provided to fabricate the hydrophobic Cellulosic Materials with any shape and size, which has promise in industrial applications.