@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 {1785, title = { Preparation and Evaluation of Glucose Based Non-Isocyanate Polyurethane Self-Blowing Rigid Foams }, journal = {POLYMERS}, volume = {11}, year = {2019}, abstract = {

A partially biobased self-blowing and self-hardening polyurethane foam from glucose-based non-isocyanate polyurethanes (g-NIPU) was prepared by reaction of glucose with dimethyl carbonate and hexamethylene diamine. However, these foam types generally require a high foaming temperature. In this paper, a self-blowing foam based on g-NIPU was prepared at room temperature by using maleic acid as an initiator and glutaraldehyde as a crosslinker. Water absorption, compression resistance, and fire resistance were tested. Scanning electron microscopy (SEM) was used to observe the foam cells structure. Middle infrared (ATR FT-MIR) and Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF) mass spectrometry were used to help to analyze the reactions during the foaming process. The results obtained showed that self- blowing rigid foams have good compression, this being directly proportional to the foam density. Increasing the amount of glutaraldehyde or reducing maleic acid thickens the cell walls and increases the density of the foams. MALDI-TOF analysis showed that g-NIPU reacts with both maleic acid and glutaraldehyde. The foams presented poor fire resistance indicating that, as for isocyanate based polyurethane foams, addition of a fire retardant would be necessary.

}, author = {X.D. XI and A. PIZZI and C. GERARDIN and H. LEI and X.Y. CHEN and S. AMIROU} } @article {1777, title = { Soy protein isolate-based polyamides as wood adhesives }, journal = { WOOD SCIENCE AND TECHNOLOGY }, volume = {54}, year = {2019}, pages = {89-102}, abstract = {

Soy protein isolate was reacted first with maleic anhydride and then hexamethylenediamine to synthesis soy protein isolate-based polyamides (SPIPA). Its bonding properties were measured by preparing laboratory three-layer plywood. Furthermore, a silane coupling agent (KH560), citric acid and maleic anhydride were added as cross-linkers to the SPIPA glue mix before hot pressing the panels. ATR FT-MIR and MALDI-ToF were used to determine the structures of the SPIPA, and thermomechanical analysis was used to analyze its thermomechanical properties. The results show that maleic anhydride reacts with amino acids in the soy protein molecule and then reacts with hexamethylenediamine to form carbamate-structured polyamides. This is confirmed by the ATR FT-MIR and MALDI-ToF results. Moreover, structural analysis indicates that a large number of branched structures are formed and occur in the SPIPA, rendering possible the formation of a network during curing, ensuring the bonding performance of the adhesive. The SPIPA adhesive presented good bonding strength and water resistance above the standard requirements of China National Standard GB/T 9846-2015. In particular, when maleic anhydride was added as a cross-linking agent, namely the SPIPA-MA adhesive, the panels\&$\#$39; dry and wet shear strengths were improved so that it can be considered as a suitable soy protein-based wood adhesive.

}, author = {X.D. XI and A. PIZZI and C. GERARDIN and X.Y. CHEN and S. AMIROU} } @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} }