@article {1847, title = { Characterization and 3D printability of poly (lactic acid)/acetylated tannin composites }, journal = { INDUSTRIAL CROPS AND PRODUCTS }, volume = {149}, year = {2020}, abstract = {

In this study, a three-dimensional (3D) printing filament prepared from poly (lactic acid) (PLA) and acetylated tannin via a twin-screw extruder was reported. The impact of acetylated tannin loading content on the final properties of the resulting composite materials and their 3D printability were investigated. The experimental results indicate that PLA can be compounded with up to 20 wt\% acetylated tannin without any obvious deterioration in the tensile property. The resulting composites acquired better degradation rate in aquatic system compared with neat PLA, especially in alkaline medium. Moreover, all composites are printable and showed generally good printing quality with brown color, however, this is limited to temperatures reasonably below 220 degrees C to avoid printing defects, especially at high loadings of acetylated tannin.

}, url = {https://hal.univ-lorraine.fr/LERMAB-UL/hal-02508080}, author = {J.J. LIAO and N. BROSSE and A. PIZZI and S. HOPPE and X.J. ZHOU and G.B. DU} } @article {1871, title = { Characterization and Preparation of Furanic-Glyoxal Foams }, journal = {POLYMERS}, volume = {12}, year = {2020}, pages = {692}, abstract = {

Synthetic foams have become an essential industrial product for a great variety of applications. Furfuryl alcohol, as a biomass chemical, was reacted with glyoxal at room temperature to prepare furanic-glyoxal rigid foams, and p-toluenesulfonic acid was used as a catalyst to initiate the reaction. Foams with different molar ratios (furfuryl alcohol/glyoxal) were prepared in this work, and uniform cells foams have been obtained. Their compression resistance, 24-h water absorption, density, and other basic properties were tested. Scanning electron microscopy (SEM) was used to observe the cellular morphology of the foams prepared, thermogravimetric analysis (TGA) helped to understand their thermal and combustion properties, and FTIR and Matrix Assisted Laser Desorption Ionisation Time of Flight (MALDI ToF) mass spectroscopy to explain the structure of the resulting foams to clarify the reactions occurring during foaming. The results show that the compression resistance of furanic-glyoxal foams declined as the furfuryl alcohol/glyoxal ratio decreases also. SEM observations revealed that foams with open-cell were obtained when furfuryl alcohol was added in greater amounts, and more closed cell structures were formed as the proportion of glyoxal increased. TGA results showed that the initial ignition temperature of furanic-glyoxal foams is similar to 200 degrees C higher than that of wood, and the smaller comprehensive combustion index S (about 0.15 x 10(-7) (\%2 K-3 min(-2))) indicates that the foam burns slowly and has poor flammability, that is, it is not easy to burn.

}, author = {X.D. XI and A. PIZZI and H. LEI and G.B. DU and X.J. ZHOU and Y.Y. LIN} } @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 {1837, title = { DEVELOPMENT OF MIMOSA TANNIN-BASED ADHESIVE CROSS-LINKED BY FURFURYL ALCOHOL- FORMALDEHYDE AND EPOXY RESINS }, journal = { WOOD RESEARCH }, volume = {64}, year = {2019}, pages = {847-858}, abstract = {

A furfuryl alcohol-formaldehyde resin was synthesized as a crosslinker in our laboratory to develop a mimosa tannin-based adhesive with good water resistance. C-13 nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight mass spectroscopy indicated that furfuryl alcohol reacted with formaldehyde under acidic conditions and that-CH (-OH) - groups to be the ones involved in the crosslinking of mimosa tannin-furfuryl alcohol-formaldehyde adhesive (TFF). The wet shear strength of TFF-bonded plywood suggested that the cured TFF adhesive was better than mimosa tannin-furfuryl alcohol (TF) adhesive. The water resistance of TFF adhesive cross-linked with 9\% epoxy resin was also higher than those of TFF and TF adhesives.

}, author = {J. ZHANG and L.H. XIONG and X.J. ZHOU and G.B. DU and J.K. LIANG and X.D. XI} } @article {1840, title = {Glucose-Biobased Non-Isocyanate Polyurethane Rigid Foams}, journal = { JOURNAL OF RENEWABLE MATERIALS }, volume = {7}, year = {2019}, pages = {301-312}, abstract = {

Glucose-based non-isocyanate polyurethanes (NIPU) were prepared by reaction of glucose with dimethyl carbonate and hexamethylene diamine. These were used to prepare partially biobased polyurethane foams by reaction with NaHCO3 as a blowing agent and addition of a silane coupling agent having different functions such as coreactant and adjuvant to obtain more uniform and smaller cells. The foams were foamed and hardened by applying heat. The foams presented very limited fire resistance indicating that as for synthetic polyurethane foams the eventual use of a fire retardant appears to be necessary. The 2 hours water absorption was used to indicate if close cells or open cells occur. More characteristic is their stress strain behaviour. While compression does indeed flatten the cell walls nonetheless the cellular structure is maintained and the cell walls have not been destroyed. This indicates a certain level of elasticity in the cell walls of formulations containing NaHCO3. In effect the macro-appearance of this foams, confirms this explanation as the foam is densified and holds together.

}, url = {http://tsp.techscience.com//uploads/attached/file/20190325/20190325065121_13446.pdf}, author = {X.D. XI and A. PIZZI and C. GERARDIN and G.B. DU} } @article {1825, title = { Non-isocyanate polyurethane adhesive from sucrose used for particleboard }, journal = { WOOD SCIENCE AND TECHNOLOGY }, volume = {53}, year = {2019}, pages = {393-405}, abstract = {

Sucrose-based non-isocyanate polyurethanes (S-NIPU) were synthesized by the already codified reaction of sucrose, dimethyl carbonate and hexamethylene diamine and used for the first time as adhesives for bonding particleboard. To decrease the NIPU adhesive curing temperature, a silane coupling agent was used as a crosslinking promoter. The performance of particleboards prepared at a press temperature of 230 degrees C, 200 degrees C and 180 degrees C and a press time of 8 min, 10 min and 12 min was tested and evaluated. The structure of the oligomers obtained was detected by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Thermomechanical analysis and differential scanning calorimetry were also used to analyze their behavior. The particleboards bonded with the S-NIPU adhesive at 230 degrees C showed excellent properties, which, however, decreased as the press time was reduced. The silane coupling agent used as a crosslinking promoter significantly reduced the curing temperature of the adhesive and allowed to obtain good bonding at a lower press temperature. The results obtained confirmed that coupling the S-NIPU adhesive with a silane used as a crosslinking promoter can yield sufficiently improved results to function as a suitable adhesive for particleboard, medium density fiberboard and other types of particulate wood panels. It was also the first time that a NIPU adhesive was used for wood bonding.

}, author = {X.D. XI and Z.G. WU and A. PIZZI and C. GERARDIN and H. LEI and B.G. ZHANG and G.B. DU} } @article {1796, title = { Superhydrophobic and Superoleophilic Fiber from Waste Bamboo Processing Residues for Oil/water Selective Separation }, journal = { JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY }, volume = {40}, year = {2019}, pages = {58-72}, abstract = {

Biomass materials have attracted increasing attention as oil absorbents for oil/water separation duo to their renewability, biocompatibility and biodegradability. However, many separation materials preparations are either rather time consuming or have suffered from the need of harsh conditions. In the present study, bamboo fiber was successfully modified to acquire simultaneously super-hydrophobic and super-oleophilic properties by just two steps: delignification and chemical vapor deposition (CVD). The morphology and properties of MTMS-bamboo fiber were characterized by SEM, FT-IR, XPS and the oil/water contact angles. Moreover, the durability, recyclability and the practical application of selective separation were studied. The analysis results disclosed that the special surface wetting properties of MTMS-bamboo fiber resulted from the silanization of the bamboo fiber surface, notably, from its water contact angle being 153 degrees and oil contact angle 0 degrees. The fiber so prepared exhibited excellent durability in several kinds of chemical solutions. The absorbed oil can be recovered by simple mechanical squeezing and the bamboo fiber maintained a high oil absorption capacity after multiple squeezing-absorption cycles. The modified fiber acted as an absorbent for hot water oil/water separation and demonstrated also a high oil separation capacity. The continuous separation efficiency of the MTMS-bamboo fiber was investigated.

}, author = {X.Y. CHEN and G.B. DU and A. PIZZI and X. XI} } @article {1815, title = { SYNTHESIS AND CHARACTERIZATION OF LIGNIN-BASED ADHESIVE CROSS-LINKED WITH FURFURYL ALCOHOL-FORMALDEHYDE AND EPOXY RESINS }, journal = { CELLULOSE CHEMISTRY AND TECHNOLOGY }, volume = {53}, year = {2019}, pages = {449-458}, abstract = {

Lignin extracted from corn stalk was cross-linked with furfuryl alcohol-formaldehyde (FF) resin in the laboratory to prepare a bio-based adhesive, with good water resistance, for producing particleboard. The results of matrix-assisted laser desorption-ionization time-of-flight mass spectroscopy and C-13 nuclear magnetic resonance spectroscopy indicated that furfuryl alcohol reacted with formaldehyde under acidic conditions. The -CH-(OH)- groups were involved in the cross-linking of the lignin-furfuryl-formaldehyde (LFF) adhesive. The internal bond strength of the LFF-bonded particleboard showed that the cured LFF was improved and had higher performance compared to the lignin-furfuryl alcohol (LF) adhesive. The LFF with 9\% epoxy resin adhesive had an excellent modulus of elasticity, which was higher than those of PF and LF adhesives.

}, author = {J. ZHANG and X.D. XI and X.J. ZHOU and J.K. LIANG and G.B. DU and J. CAI} } @article {1793, title = { Tannin-based adhesive cross-linked by furfuryl alcohol-glyoxal and epoxy resins }, journal = { INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES }, volume = {94}, year = {2019}, pages = {47-52}, abstract = {

To prepare a natural tannin-based adhesive with good water resistance, an environment friendly furfuryl alcohol-glyoxal resin (FG) synthesized in the laboratory was developed as a cross-linker for tannin-based adhesives. C-13 Nuclear Magnetic Resonance (NMR) and Matrix-Assisted Laser Desorption-Ionization Time-of-Flight (MALDI-TOF) mass spectroscopy results indicated that furfuryl alcohol and glyoxal reacted under acidic conditions and that the -CH-(OH)- groups could be shown to be the ones involved in the cross-linking of the tannin-furfuryl-glyoxal adhesive (TFG). The results for the wet shear strength of TFG-bonded plywood showed that the cured TFG was improved and better than that bonded with a tannin-furfuryl alcohol (TF) adhesive. Moreover, the TFG adhesive cross-linked with 12\% epoxy resin (EPR) presented a good water resistance. It had a modulus of elasticity (MOE) higher than that of tannin-furfuryl alcohol-formaldehyde (TFF), TF and phenol-formaldehyde (PF) adhesives.

}, author = {J. ZHANG and X.D. XI and J.K. LIANG and A. PIZZI and G.B. DU and S.D. DENG} } @article {1765, title = { AN ECO-FRIENDLY UREA-FORMALDEHYDE RESIN: PREPARATION STRUCTURE AND PROPERTIES }, journal = { WOOD RESEARCH }, volume = {63}, year = {2018}, pages = {45-56}, abstract = {

The preparation, structures and properties of UF resin prepared with concentrated formaldehyde at a low molar ratio F/U=1.1 were studied in this paper. According to the results obtained from C-13-NMR, FT-IR and DMA, UF resin prepared with concentrated formaldehyde showed better mechanical properties and heat resistance and lower formaldehyde emission responsible for its high degree of polycondensation and crosslinking than that of UF prepared with common formaldehyde, but its stability was so bad due to its high content of ether bridges. However, it was stated that adding hydrolyzed soy protein to this UF resin at the first alkali preparation stage of \"alkali-acid-alkali\", its stability got improved due to the increase of methylene bridges, which was the key contribution to polycondensation.

}, author = {Z.G. WU and X.D. XI and L.P. YU and L. SU and H. LEI and G.B. DU and Z.W. YIN} }