@article {1867, title = { Beech wood treated with polyglycerol succinate: a new effective method for its protection and stabilization }, journal = { HOLZFORSCHUNG }, volume = {74}, year = {2020}, pages = {351-361}, abstract = {

This paper deals with an original and non-biocidal chemical treatment consisting of a vacuum/pressure impregnation step of beech wood with a water-borne mixture made from heat-activated condensation of succinic anhydride (SA) and glycerol (G). Chemical structures of adducts were established using matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF) investigations. Beech wood was impregnated and cured in order to induce in situ polymerization of glycerol/succinic adducts (GSA) in the cell walls, leading to the formation of polyglycerol succinate (PGS) polyester. Various treatment conditions were investigated depending on the duration (6-72 h) and curing temperature (103-160 degrees C). Weight percent gains (WPGs) ranging between 40 and 60\% were obtained. Attenuated total reflectance-middle infrared spectroscopy (ATR-MIR) and carbon-13 nuclear magnetic resonance (C-13-NMR) spectroscopy confirmed polyester formation. A curing temperature of 160 degrees C was found to be the best condition to totally avoid polymer leaching, and brought the anti-swelling efficiency (ASE) up to 64\%. Decay resistance of PGS-treated wood against Trametes versicolor and Coniophora puteana was also strongly temperature and time dependent: performances fit with the EN113 standard requirements if a curing temperature of 160 degrees C was applied.

}, author = {C. L{\textquoteright}HOSTIS and E. FREDON and M.F. THEVENON and F.J. SANTIAGO-MEDINA and P. GERARDIN} } @article {1861, title = { Condensed tannin-glucose-based NIPU bio-foams of improved fire retardancy }, journal = { POLYMER DEGRADATION AND STABILITY }, volume = {175}, year = {2020}, abstract = {

Glucose-based self-blowing non-isocyanate polyurethanes foams were prepared in our previous work. They showed excellent properties comparable to commercial foams by just using a simple preparation procedure. These foams, nevertheless, present a critical drawback that is their flammability. In the research presented here a natural phenolic compound, condensed tannin, was tested as a flame-retardant to improve the fire resistance of glucose-based NIPU foams. A number of tannin-substituted glucose-based NIPU foams (mimosa tannin replacing glucose at 0\%, 25\% and 50\%, respectively) were prepared and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TG), ignition experiment and limiting oxygen index (LOI). Other physical and mechanical properties, such as foaming processes, density, compression strength, etc. were also investigated. The results indicated that the tannin-modified glucose-based NIPU foams (T/G (1/3)-Fs and (T/G (1/1)-Fs)) exhibit smaller mean cell size, improved compression strength and higher density than (T/G (0/4)-Fs). The FT-IR analysis showed that urethane linkages were formed, the chemical structure of glucose-based NIPU foam being nonetheless preserved even if the glucose was partially replaced by the condensed tannin. Thermogravimetric analysis showed that the presence of condensed tannin decreased the thermal stability of the tannin-glucose NIPU foam composites slightly. In addition, ignition experiments were also carried out in which the glucose-based NIPU foams with a condensed tannin showed longer burning time than neat (T/G (0/4)-Fs). Finally, limiting oxygen index (LOI) values from 17.5\% to 25.5\%, show a higher value with the increasing condensed tannin substitution.

}, author = {X.Y. CHEN and J.X. LI and X.D. XI and A. PIZZI and X.J. ZHOU and E. FREDON and G.B. DU and C. GERARDIN} } @article {1885, title = { Oxidized demethylated lignin as a bio-based adhesive for wood bonding }, journal = { JOURNAL OF ADHESION }, year = {2020}, abstract = {

Lignin was successfully modified to prepare a bio-based wood adhesive by just two synthesis steps: demethylation and periodate oxidation. Fourier Transform Infrared Spectroscopy (FT-IR), Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) Mass Spectrometry and Thermomechanical Analysis (TMA) were combined to characterize the bio-based adhesives obtained. Furthermore, the adhesion performance of the bio-based lignin adhesive was measured by testing the tensile shear strength of the bonded joints. The results show that demethylated lignin gives to the wood joint acceptable dry shear strength, but no wet shear strength. Thus, sodium peroxide (NaIO4) oxidant was used to improve the bonding performance of lignin-based adhesives. The optimal formulation for oxidized demethylated lignin adhesives was found to be by 20\% addition of NaIO4. The adhesive presented is a lignin-derived non- aldehyde addition, high biomass content, and its preparation is convenient, low-cost product and can be applied to wood bonding.

}, author = {X.Y. CHEN and X.D. XI and A. PIZZI and E. FREDON and G.B. DU and C. GERARDIN and S. AMIROU} } @article {1865, title = { Preparation and Characterization of Condensed Tannin Non-Isocyanate Polyurethane (NIPU) Rigid Foams by Ambient Temperature Blowing }, journal = {POLYMERS}, volume = {12}, year = {2020}, abstract = {

Ambient temperature self-blowing mimosa tannin-based non-isocyanate polyurethane (NIPU) rigid foam was produced, based on a formulation of tannin-based non-isocyanate polyurethane (NIPU) resin. A citric acid and glutaraldehyde mixture served as a blowing agent used to provide foaming energy and cross-link the tannin-derived products to synthesize the NIPU foams. Series of tannin-based NIPU foams containing a different amount of citric acid and glutaraldehyde were prepared. The reaction mechanism of tannin-based NIPU foams were investigated by Fourier Trasform InfraRed (FT-IR), Matrix Assisted Laser Desorption Ionization (MALDI-TOF) mass spectrometry, and C-13 Nuclear Magnetic Resonance (C-13 NMR). The results indicated that urethane linkages were formed. The Tannin-based NIPU foams morphology including physical and mechanical properties were characterized by mechanical compression, by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). All the foams prepared showed a similar open-cell morphology. Nevertheless, the number of cell-wall pores decreased with increasing additions of glutaraldehyde, while bigger foam cells were obtained with increasing additions of citric acid. The compressive mechanical properties improved with the higher level of crosslinking at the higher amount of glutaraldehyde. Moreover, the TGA results showed that the tannin-based NIPU foams prepared had similar thermal stability, although one of them (T-Fs-7) presented the highest char production and residual matter, approaching 18.7\% at 790 degrees C.

}, author = {X.Y. CHEN and X.D. XI and A. PIZZI and E. FREDON and X.J. ZHOU and J.X. LI and C. GERARDIN and G.B. DU} } @article {1745, title = { Improvement of beech wood properties by in situ formation of polyesters of citric and tartaric acid in combination with glycerol }, journal = { HOLZFORSCHUNG }, volume = {72}, year = {2018}, pages = {291-299}, abstract = {

Beech wood has been treated by impregnation followed by heating at various temperatures with solutions containing citric acid (CA) or tartaric acid (TA) alone or in combination with glycerol (G), i.e. with G+CA and G+TA. The resulting modified woods were tested in terms of resistance to leaching, durability and dimensional stability. These properties are improved as a function of heating temperature, which leads to higher levels of poly-esterification involving grafting onto wood simultaneously with thermal degradation of wood. Dimensional stability of all treated wood was increased, but glycerol does not have a positive effect with this regard. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy contributed to understanding the effects of the different treatments. In situ polymerization of G+TA at 140 degrees C increased the bending resistance, while G+CA polymerization does not compensate notably the mechanical weakness induced by thermal degradation of wood at higher temperatures. However, G+CA treatment is more efficient regarding leaching and decay resistance, than that with G+TA.

}, author = {C. L{\textquoteright}HOSTIS and M.F. THEVENON and E. FREDON and P. GERARDIN} } @article {1180, title = {Flexible tannin-furanic films and lacquers.}, journal = {Ind. Crops \& Prod.}, volume = {61}, year = {2014}, month = {2014}, chapter = {352}, author = {M.C. BASSO and C. LACOSTE and A. PIZZI and E. FREDON and L. DELMOTTE} } @article {613, title = {Optimization of acid pretratment in order to increase the phenolic content of Picea abies bark by surface response methodology }, journal = {BioResources}, volume = {8}, year = {2013}, month = {2013}, chapter = {1258-1273}, author = {X. DURET and E. FREDON and E. MASSON and L. DESHARNAIS and P. GERARDIN} } @article {690, title = {Synthesis of Resins with Ozonized Sunflower Oil and Radiata Pine Tannins}, journal = {J.Renew.Mat.}, volume = {1}, year = {2013}, month = {2013}, chapter = {242-252}, author = {M. THEBAULT and A. PIZZI and E. FREDON} } @article {560, title = {Spruce bark hydrolysis to optimize phenolic content}, journal = {Cellulose Chem. Technol.}, volume = {46}, year = {2012}, month = {2012}, chapter = {541-550}, author = {X. DURET and E. FREDON and P. GERARDIN and E. MASSON} }