Polymerization Of Furfuryl Alcohol Research Articles

Analytical and experimental studies on stress capacity with modified wood members under combined stresses

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints.

Study and Optimization of the Polymerization Parameter of Furfuryl Alcohol by Algerian Modified Clay

Furfuryl alcohol (FA) which is derived from lignocellulosic biomass polymerizes into poly(furfuryl alcohol) (PFA) under acidic catalysis. A greener and more sustainable catalytic pathway was suggested in order to replace hazardous acidic catalysts by Algerian modified clay (maghnite-H+ or mag-H+). The possibility of the polymerization of FA by mag-H+ was reported, and it was found that the polymerization of FA was initiated by mag-H+ in dichloromethane. The reaction parameters such as time, temperature, and mag-H+/monomer weight ratio were optimized to improve the yield of the reaction and increase the average molecular weight. The kinetics indicated that the polymerization rate is first-order with respect to monomer concentration. The structural analysis of the polymer was carried out by IR, 1H NMR and 13C NMR spectroscopies. Thermal properties of the polymer were studied by TGA and DSC analyses. The novelty of this work is the exploitation of local clay that is widely available, inexpensive and has excellent properties and high quality features, which make it the subject of continuing research. These results will be a starting point and an essential reference for a comparative study, with the results of future work concerning the synthesis of PFA/maghnite nanocomposites.

Fabrication of porous carbon/TiO₂ composites through polymerization-induced phase separation and use as an anode for Na-ion batteries.

Polymerization-induced phase separation of nanoparticle-filled solution is demonstrated as a simple approach to control the structure of porous composites. These composites are subsequently demonstrated as the active component for sodium ion battery anode. To synthesize the composites, we dissolved/dispersed titanium oxide (anatase) nanoparticles (for sodium insertion) and poly(hydroxybutyl methacrylate) (PHBMA, porogen) in furfuryl alcohol (carbon precursor) containing a photoacid generator (PAG). UV exposure converts the PAG to a strong acid that catalyzes the furfuryl alcohol polymerization. This polymerization simultaneously decreases the miscibility of the PHBMA and reduces the mobility in the mixture to kinetically trap the phase separation. Carbonization of this polymer composite yields a porous nanocomposite. This nanocomposite exhibits nearly 3-fold greater gravimetric capacity in Na-ion batteries than the same titanium oxide nanoparticles that have been coated with carbon. This improved performance is attributed to the morphology as the carbon content in the composite is five times that of the coated nanoparticles. The porous composite materials exhibit stable cyclic performance. Moreover, the battery performance using materials from this polymerization-induced phase separation method is reproducible (capacity within 10% batch-to-batch). This simple fabrication methodology may be extendable to other systems and provides a facile route to generate reproducible hierarchical porous morphology that can be beneficial in energy storage applications.

Wood/Polymer Nanocomposites Prepared by Impregnation with Furfuryl Alcohol and Nano-SiO2

Wood/polymer nanocomposites were prepared by vacuum impregnation of furfuryl alcohol (FA) and nano-SiO2 into fast-growing poplar wood. The nano-SiO2 was mixed with FA solution, followed by in-situ polymerization of FA. The properties of nanocomposites and the effects of nanoparticles on these properties were investigated. Wood physico-mechanical properties, such as dimensional stability, density, water uptake, and surface hardness, were significantly improved. Moreover, the addition of nano-SiO2 improved the surface hardness and dimensional stability of wood and kept the excellent properties of FA-treated wood. Thermogravimetric analysis indicated that the effect of nano-SiO2 on thermostability was hindered. X-ray photoelectron spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy showed that nano-SiO2 was successfully incorporated into wood via the action of FA, and diffused into the wood lumen and cell wall. X-ray diffraction results indicated the weakening of the crystallinity in the treated wood was due to the polymerization of FA.

Changes in Cell Wall Dimensions during the Different Stages of Furfuryl Alcohol Modification

Furfuryl alcohol modification of wood is a well-known process for wood property enhancement. The present project focuses on veneer molding for high-value applications using the plasticizing effect of furfuryl alcohol. Adding maleic anhydride to furfuryl alcohol leads to an acid-catalyzed polymerization of furfuryl alcohol at elevated temperatures, fixing the shape of the veneer. In contrast to water or water vapor treatment, furfuryl alcohol-modified cell walls face a lower degree of shrinkage due to the polymer formation and possibly experience less drying-induced cracks. Earlier studies show a distinct influence of maleic anhydride on the curing of furfuryl alcohol. To determine the impact of different maleic anhydride contents on the polymer formation and the corresponding shrinkage of wood cell walls, microscopic studies were carried out on various maple microtome sections (Acer sp.), i.e., when dry, water-impregnated, after furfuryl alcohol impregnation, and after curing at elevated temperatures. At each state, the cell walls of 30 appointed early wood cells were determined by cell wall area measurements. The lowest shrinkage of impregnated samples was realized by using 10 wt% maleic anhydride in the impregnation solution and after 48 h soaking. Here, cell wall shrinkage could be reduced by approx. 42.6% compared to water-impregnation.

Synthesis of carbon with bimodal porosity by simultaneous polymerization of furfuryl alcohol and phloroglucinol

Carbon materials with bimodal porosity have shown enhanced performance in a wide variety of applications including catalysis, energy storage and fluid separation. Presence of mesoporosity is essential to lower the mass transfer limitation imposed by the microporous nature of the carbons. The synthesis approaches used to prepare bimodal carbons with controlled micro/mesopore size and narrow pore size distribution, usually involve multi step processes and the use of harsh chemicals and solvents. Herein, we present a simple one step method that can be used to synthesize carbon with bimodal pore size distribution. Simultaneous polymerization of furfuryl alcohol and phloroglucinol-formaldehyde in the presence of a structure-directing agent (Pluronic F-127) was carried out and the resultant polymer was pyrolyzed to yield the bimodal carbon. Effect of polymerization conditions such as concentrations of monomer, initiator and surfactant on the bimodal pore size distribution of the carbon was studied in detail. Pyrolyzed precursors form carbons with narrow mean micropore size of 0.5nm and mean mesopores ranging from 3.5 to 6nm. The range of the mesopore size could be altered by varying the polymerization parameters (acid and surfactant concentration) as well as selective oxidation using CO2 gas.

Facile and Efficient Conversion of Furfuryl Alcohol into n-Butyl Levulinate Catalyzed by Extremely Low Acid Concentration

Alkyl levulinates have been identified as promising chemicals with various industrial applications. Here, a catalytic process for the synthesis in an n-butanol medium of n-butyl levulinate via the alcoholysis of biomass-derived furfuryl alcohol was performed using an extremely low concentration of sulfuric acid (≤ 0.01 M) as the catalyst. A study was conducted that was designed to optimize the process variables, which include acid concentration, reaction temperature, initial substrate concentration, and water content, as a function of time. The optimum conditions resulted in a furfuryl alcohol conversion of nearly 100% and a high n-butyl levulinate yield of up to 97%, which was confirmed by isolated yield. An advantage of this catalyst system is that negligible undesired oligomeric products were formed from the side reaction for the polymerization of furfuryl alcohol, the catalyst cost is low, and less solid waste was discharged from the neutralization of spent acid. Overall, this catalytic strategy is a facile, efficient, and economical approach to the conversion of biomass-derived furfuryl alcohol into alkyl levulinates.

Preparation of Ultrafine Carbon Spheres by Controlled Polymerization of Furfuryl Alcohol in Microdroplets

Carbon microspheres with mean particle sizes of 0.7–1.2 μm were prepared by polymerization of furfuryl alcohol (FA) in H2SO4 solution droplets without any surfactant, followed by pyrolysis. FA was introduced by diffusion from FA-containing oil phase into the droplets formed in an interdigital micromixer. The oil to aqueous phase flow rate ratio and the FA and H2SO4 concentrations should be kept at medium values. A decrease in the total flow rate ratio, oil to aqueous phase flow rate ratio, or FA concentration results in small-sized carbon microspheres, and a decrease in the FA or H2SO4 concentration leads to formation of the carbon microspheres exhibiting rough surface. The carbon microspheres show good dispersity in ethanol and microporosity. Their particle sizes could be further reduced to 150 nm by using polyvinyl pyrrolidone, and their mesoporosity can easily be endowed by adding silica nanoparticles in the droplets.

Study of Properties of Expanded Graphite – Polymer Porous Composite by Acoustic Emission Method

Abstract The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.

Influence of furanic polymers on selectivity of furfural rearrangement to cyclopentanone

The influence of furanic polymers upon the activity and selectivity of Ni, Pd, Pt catalysts in rearrangement of furfural to cyclopentanone, and its consecutive hydrogenation to cyclopentanol in an aqueous phase has been studied. The coverage of surface of heterogeneous catalyst by the furanic polymers suppresses or almost completely inhibits hydrogenation of cyclopentanone to cyclopentanol. Furanic polymers are created on catalyst surface by partial polymerization reaction of furfuryl alcohol which is in aqueous medium catalyzed by H+ protons formed by dissociation of water at reaction temperatures. Thermogravimetric and XPS measurements confirmed the presence of polymers on catalyst surface. Owing to the modification of catalyst surface by the polymer bearing furan moieties constituents the dominant reaction product is despite high reaction temperature (175°C) and hydrogen pressure (80bar), cyclopentanone, and not expected more stable cyclopentanol. Very high selectivity of furfural rearrangement to cyclopentanone can be achieved by influencing the balance between the rates of formation of furfuryl alcohol polymers on the catalyst surface and their decomposition.

Platinum embedded within carbon nanospheres for shape selective liquid phase hydrogenation

Reactant shape selective catalysis occurs when substrates of different sizes and shapes are consumed at different rates over catalysts that combine molecular sieving transport processes with reaction. By contrast the same substrates react at nearly equivalent rates over catalysts that have large, open pores that do not induce any form of molecular sieving. Here we describe the design and synthesis of reactant shape selective catalysts for liquid phase hydrogenation reactions. Using an emulsion polymerization of furfuryl alcohol, we have made catalysts that consist of microporous carbon nanospheres within which are embedded platinum nanoparticles. The porosity of the carbon spheres was found to be a key parameter affecting catalyst activity and selectivity; porosity was varied by adding pore forming agents, such as polyethylene glycol with different molecular weights, during synthesis, or by mild oxidation of the as-synthesized catalyst using carbon dioxide. In addition to increasing porosity to reduce mass transfer limitations, a synthesis of smaller carbon spheres (<200nm) was devised to reduce the micropore diffusion length. Decreasing the particle size of the catalyst by adjusting the surfactant composition during polymerization, improved the effectiveness factor by approximately one order of magnitude making it as active as a comparable standard metal catalyst.

Controlled cationic polymerization of furfuryl alcohol

CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system was used successfully in the controlled cationic polymerization of furfuryl alcohol initiated with benzyl bromide in acetonitrile. Polymerizations were carried out at 110°C open to air. The effect of reaction time, amount of initiator and solvent on the rate of polymerization was studied. The linear kinetic plot of ln([M]o/[M]) versus polymerization time, linear dependence of the molecular weight on the monomer conversion and low polydispersity of the polymers (1.07–1.50) showed the characteristics of the controlled polymerization. Soluble polymers with Mn up to 6.6kg/mol were obtained. The structural analysis of the polymer was carried out by 1H NMR, 13C NMR, FTIR and UV–VIS spectroscopies. Formation of carbonyl groups and CH2OCH2 bridges on poly(furfuryl alcohol) chains were observed. Thermal properties of the polymer were studied by DSC and TGA analyses.

Effect of Maleic Anhydride Content and Ethanol Dilution on the Polymerization of Furfuryl Alcohol in Wood Veneer Studied by Differential Scanning Calorimetry

The polymerization kinetics of furfuryl alcohol in wood veneer were studied using differential scanning calorimetry (DSC) and were compared with weight gains of treated wood veneers. Maleic anhydride was used as the reaction initiator. DSC data were obtained for samples of the veneers that had been impregnated with neat furfuryl alcohol or with furfuryl alcohol diluted with ethanol, and using two ratios of maleic anhydride to furfuryl alcohol. The high ratio of maleic anhydride to furfuryl alcohol (1:9) favoured rapid polymerization at a lower temperature, whereas the lower ratio (1:19) resulted in a relatively slower rate of polymerization, which required higher temperatures to affect the reaction. A higher temperature also led to an increase in furfuryl alcohol evaporation from the prepared veneers. The DSC data was compared with data obtained from furfuryl alcohol impregnated wood veneers but without the addition of maleic anhydride. DSC data is in good agreement with weight percentage gains (WPGs) obtained for samples impregnated with differently composed solutions. While higher maleic anhydride contents led to higher WPGs, ethanol dilution inhibits polymer formation, resulting in lower WPG.

Effects of solvent on the furfuryl alcohol polymerization reaction: UV Raman spectroscopy study

The effect of alcohol as a solvent on the acid-catalyzed conversion of furfuryl alcohol (FA) into polymerized furfuryl alcohol (PFA) has been studied by UV Raman spectroscopy. The major peak intensity ratios were compared to gain quantitative information about the extent of polymerization in various solvents. The reaction rate of the polymerization has been found to significantly decrease with increasing concentrations of ethanol or butanol (n-butanol and iso-butanol). Compared to ethanol, longer or branched chain alcohols such as n-butanol and iso-butanol can marginally reduce the acid-catalyzed polymerization at room temperature. The plot of reciprocal intensity of the characteristic Raman band of FA vs. the reaction time suggests that the polymerization reactions follow second-order kinetics.

Simple Cocasting Method to Prepare Magnetic Mesoporous FePt/C Composites and Their Protein Adsorption Property

A simple cocasting method has been developed to prepare magnetic mesoporous FePt/C composites with superparamagnetic FePt nanoparticles embedded in carbon walls. Furfuryl alcohol, iron(III) acetylacetonate (Fe(acac)3), and platinum(II) acetylacetonate (Pt(acac)2) were used as the carbon and FePt nanoparticle precursors to be simultaneously incorporated into the channels of mesoporous silica SBA‐15 template by the incipient wetness impregnation technique. After the polymerization of furfuryl alcohol, the carbonization in argon, and the removal of silica template, magnetic mesoporous FePt/C composites were finally obtained. Magnetic mesoporous FePt/C composites have high surface area of 1244 m2/g and narrow mesopore size distribution peaked at 4.93 nm. FePt nanoparticles were well embedded in mesoporous carbon walls, and mesoporous FePt/C composites exhibit superparamagnetic behavior. Using cytochrome c (Cyt c), myoglobin (Mb), and bovine serum albumin (BSA) as model proteins, the adsorption capacities of Cyt c, Mb, and BSA on magnetic mesoporous FePt/C composites can reach ca. 200, 162, and 121 μg/mg, respectively. These results indicated that mesoporous FePt/C composites have potential as magnetically separable adsorbent for biomolecules separation.

On the effects of emulsion polymerization of furfuryl alcohol on the formation of carbon spheres and other structures derived by pyrolysis of polyfurfuryl alcohol

Carbon spheres were synthesized by emulsion polymerization and pyrolysis of polyfurfuryl alcohol. Pluronic F-127 was used as the structure-directing agent to synthesize polymer spheres that after pyrolysis led to carbon spheres with average sizes from 50nm to few micrometers in diameter depending upon the conditions of polymerization. As-synthesized carbon spheres possess high surface areas of around 480m2/g with an average mean pore size of 0.5nm. These spheres can be activated using carbon dioxide to create much higher surface areas (>1500m2/g). Different compositional regions of the pseudo-ternary phase diagram of surfactant/monomer/solvent were explored in order to determine the effects of changes in the emulsion polymerization variables on the kinds of carbon morphologies that could be derived from polyfurfuryl alcohol after pyrolysis. The diameter of the carbon spheres was found to be sensitive to monomer and surfactant concentrations, acid molarity and solvent composition. In general, the diameter of the spheres grew with increasing furfuryl alcohol concentration and decreasing surfactant concentration, respectively. By varying the acid concentration and solvent composition, a minimum diameter for spheres was found. The formation and size of the spheres are strongly influenced both by micelle growth and the polymerization mechanism.

Synthesis and Photocatalytic Activity of Titania Monoliths Prepared with Controlled Macro- and Mesopore Structure

Herein, we report a one-pot synthesis of crack-free titania monoliths with hierarchical macro-mesoporosity and crystalline anatase walls. Bimodal macroporosity is created through the polymer-induced phase separation of poly(furfuryl alcohol). The cationic polymerization of furfuryl alcohol is performed in situ and subsequently the polymer becomes immiscible with the aqueous phase, which includes titanic acid. Addition of template, Pluronic F127, increases the mesopore volume and diameter of the resulting titania, as the poly(ethylene glycol) block interacts with the titania precursor, leading to assisted assembly of the metal oxide framework. The hydrophobic poly(propylene glycol) micelle core could itself be swollen with monomeric and oligomeric furfuryl alcohol, allowing for mesopores as large as 18 nm. Variations in synthesis parameters affect porosity; for instance furfuryl alcohol content changes the size and texture of the macropores, water content changes the grain size of the titania and Pluronic F127 content changes the size and volume of the mesopore. Morphological manipulation improves the photocatalytic degradation of methylene blue. Light can penetrate several millimeters into the porous monolith, giving these materials possible application in commercial devices.

Complex Kinetic Pathway of Furfuryl Alcohol Polymerization Catalyzed by Green Montmorillonite Clays

Furfuryl alcohol (FA) which is derived from lignocellulosic biomass polymerizes into poly(furfuryl alcohol) (PFA) under acidic catalysis. A greener and more sustainable catalytic route was proposed in order to replace hazardous acidic catalysts. Organically modified montmorillonite (Org-MMT) and, in comparison, sodium MMT (Na-MMT) are used to evaluate the catalytic effect on the FA polymerization. X-ray diffraction (XRD) and transmission electronic microscopy (TEM) show that clay layers have been exfoliated during polymerization. Additional FTIR spectroscopy measurements confirm that furanic oligomers have intercalated between clay layers by cation exchange. An original combination between chemorheological and model-free kinetic analysis allows highlighting the influence of MMT on the overall polymerization pathway. The octadecyl ammonium cation (ODA) was also used as homogeneous acidic catalyst to highlight the specific role of this interlayer cation present in Org-MMT. Interestingly, FA/Org-MMT polymerizes more rapidly than FA/ODA but initiation of polymerization is slightly shifted to higher temperature due to initial intercalation between MMT layers. Then, the dual acidic character (Lewis + Brönsted) of Org-MMT leads to gelation at early stage of polymerization. The results clearly show that exfoliation of MMT layers increases the efficiency of collisions.

Electrochemical effect of carbon nanospheres on an AB5 alloy

In this paper, the effect of the addition of carbon nanospheres (CNE) by high energy mechanical milling to the active material of the negative electrode of a Nickel–Metal Hydride (Ni–MH) battery is studied. The hydrogen storage alloy (MH) is an AB5-type (Lm0.95Ni3.8Co0.3Mn0.3Al0.4), where Lm is a mixture of rare earths, and it was prepared by melting the constituent elements in an electric induction furnace. The CNE were synthesized by two-stage polymerization of furfuryl alcohol, drying and carbonization, and were subsequently doped with different proportions of Ni (0–20%) by the method of wet impregnation with Nickel nitrate hexahydrate. The behavior of electrochemical cells consisting of a working electrode with 45% of MH, 5% of CNE pure and doped with different proportions of Ni and 50% carbon Teflon acting as electrical and mechanical support, a counter electrode of Ni mesh, and a reference electrode Hg/HgO was studied. The experiments covered electrochemical activation and cycle stability, rate capability and electrochemical impedance spectroscopy. The results show that the addition of CNE improves the electrochemical performance, and particularly the CNEs pure and doped with 20% of Ni present the best electrochemical performance in discharge capacity, rate capability and impedance spectroscopy.

Characterization of the polymerization of furfuryl alcohol during roasting of coffee

The polymerization of furfuryl alcohol contributes to the formation of the brown colour in heated foods, in addition to the Maillard and caramelization reactions. During the heating of food, furfuryl alcohol is formed via the degradation of quinic acid or 1,2-enediols. Furfuryl alcohol is a mutagenic compound. In acidic conditions it is able to polymerize and form aliphatic polymers that show a brown colour. Herein we show that furfuryl alcohol polymerizes in a model system by incubating it in 1 M HCl at room temperature. Some of the reaction products are dimers, trimers, tetramers, and pentamers with methylene linkages. The degree of polymerization and the amount of those furfuryl alcohol oligomers increased with increasing reaction time. The results of this model system were used to characterize the polymerization of furfuryl alcohol which is produced during roasting of coffee. The coffee was roasted at 210 °C for 2, 3, 4, 5, and 6 min with a home coffee roaster. Furfuryl alcohol and its dimer were found in roasted coffee after 2 and 3 min of roasting respectively, reaching a maximum amount after 4 min. Perhaps due to further reactions, the dimeric furfuryl alcohol concentration starts to decrease after 4 min. We propose that the polymers of furfuryl alcohol contribute to the brown colour of roasted foods.