Preparation of Cu-MgO catalysts with different copper precursors and precipitating agents for the vapor-phase hydrogenation of furfural

This article presents the effects of three copper precursors and four precipitating agents on the catalytic performance of the corresponding co-precipitated Cu-MgO catalysts in the vapor-phase hydrogenation of furfural. The chemical and physical properties were analyzed by means of XRD, BET, SEM, and EDX techniques. The nitrate precursor provided the highest performance (conversion of ~89%). Whereas, the catalyst prepared with NaOH was the most efficient (furfuryl alcohol yield of >90%) during 240 min; the most durable conversion (~95%) was assured with Na_2-CO₃, and the highest selectivity to furfuryl alcohol (>97%) was achieved with K₂CO₃ as the precipitating agent. The least efficient catalyst (prepared with ammonium carbonate) led to 5-methylfurfural and 2,2-methylenebisfuran as the main byproducts. The major byproducts over the rest of the catalysts included tetrahydrofurfuryl alcohol, furfuryl ether, 1-pentanol, and 2-methylfuran. An increasing trend of furfuryl alcohol selectivity with time-on-stream was evident for all of the catalysts.     

Thermally reversible and self‐healing novolac epoxy resins based on Diels–Alder chemistry

The modified novolac epoxy resins with furan pendant groups were prepared by novolac epoxy resin and furfuryl alcohol and then crosslinked by bifunctional maleimide via Diels–Alder (DA) chemistry to obtain the thermally reversible and self‐healing novolac epoxy resins. The as‐prepared crosslinked novolac epoxy resins were characterized by FT‐IR, NMR, TGA, and DMA. The results indicate that the novel crosslinked novolac epoxy resins present higher storage modulus (2.37 GPa at 30°C) and excellent thermal stability (348°C at 5% mass loss). Furthermore, the thermal reversible and self‐healing properties were studied in detail by DSC, SEM, thermal re‐solution, and gel–solution–gel transition experiments. All the results reveal that the crosslinked novolac epoxy resins based on DA reaction can be used as smart material for the practical application of electronic packaging and structural materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42167.     

新型呋喃树脂的制备与改性

以糠醇和糠醛为原料在草酸催化作用下发生缩聚制取新型呋喃树脂。研究表明,当糠醇与糠醛的质量比为7：3,草酸用量为原料质量的0．33％,在回流温度下反应3．5h时,反应制得的呋喃树脂黏度达到78s,且与水玻璃混合良好,采用对苯甲酸作固化剂固化后耐水、耐高温性能优,从而达到改性水玻璃胶泥的目的。采用尿素与甲醛替代所有的糠醛与大部分的糠醇进行缩聚合成出脲醛呋喃树脂。研究表明,当n（尿素）：n（甲醛）：n（糠醇）为3：1：2,在回流温度下反应3．5h,可获得性价比优的改性呋喃树脂。     

Effect of furfuryl alcohol addition on the cure of furfuryl alcohol resin used in the glassy carbon manufacture

Glassy carbon can be manufactured practically without pores, named Monolithic Vitreous Carbon (MVC) or presenting up to 98% in transport pore volume, foam form, denominated Reticulated Vitreous Carbon (RVC). The glassy carbon processing is affected by some processing parameters, among them it can be cited the resin viscosity. The present work involves the optimization of RVC manufacture by monitoring the polyurethane (PU) foam impregnation with furfuryl alcohol resin with different viscosity values, which were obtained by dilution of the resin with different amounts of furfuryl alcohol. The resin samples used in the PU impregnation were characterized by thermal and rheological analyses. These results were correlated with scanning electron microscopy observations and compression test results of the impregnated polyurethane foam. The results show that the rheological behavior of the resin has significant influence on the polymerization step, affecting the homogeneity of impregnated foam and, consequently, its final properties, mainly the mechanical one. The impregnated foam prepared with the furfuryl alcohol resin diluted with 10% of furfuryl alcohol (η = 11.4 Pa s) showed higher compression values (0.26 MPa). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fiberboards Based on Sugarcane Bagasse Lignin and Fibers

Summary: Fiberboards were prepared using phenolic type resins (phenol‐formaldehyde) and sugarcane bagasse fibers. Lignin extracted through an organosolv process from sugarcane bagasse was used as substitute of phenol in phenolic resins from 40 (lignin‐phenol‐formaldehyde) to 100 wt.‐% (lignin‐formaldehyde) substitution. Some of the fibers were chemically modified by oxidation with chlorine dioxide and treatment with furfuryl alcohol (FA), leading to fibers coated with polyfurfuryl alcohol. Thermal analysis (DSC and TGA) of the prepolymers allowed setting up an efficient curing to prepare fiberboards. Impact strength and water absorption were measured showing the importance of the curing pressure to obtain good performance. When chemically modified fibers were used to prepare board samples, enhanced durability against white root fungi is observed, and to a less degree against brown root fungi. Sugarcane bagasse fiberboards were prepared from prepolymers where lignin substituted phenol up to 100%. This replaces these materials in advantageous position, relating to those prepared from phenol‐formaldehyde resins, due to their high content of renewable raw materials. The results obtained are promising for the utilization of sugarcane bagasse as raw materials for preparing fiberboards to be used in tropical areas.

Stabilization of sugarcane bagasse fiberboards made with unmodified and modified (ClO₂ + furfuryl alcohol) fibers and phenolic resin after 8 weeks exposure against fungi.     

A study of the low molecular weight components of furfuryl alcohol polymers

Low molecular weight components of both an acid-polymerized and a γ-alumina polymerized furfuryl alcohol polymer were separated by gas chromatography utilizing a Porapak type P-S column packing. The identities of the separated polymer components were established by infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance analysis. Volatile constituents found to be common to both furfuryl alcohol resin types were: furfuryl alcohol, water, difurylmethane, difurfuryl ether, and 2,5-difurfurylfuran. Also, 5-furfurylfurfuryl alcohol was found to be present only in the acid-polymerized resin, and 4-furfuryl-2-pentenoic acid γ-lactone was a constituent only of the γ-alumina-polymerized resin. Contrary to expectation, no esters of levulinic acid were found among the low molecular weight components of the γ-alumina-polymerized furfuryl alcohol polymer.     

Seepage Characteristics of Emulsion with Phase Transition Behaviors

Petroleum resins have excellent thermal tolerance and selective plugging capability. As the environment temperature exceeds their softening point, petroleum resins transform from a solid into a viscous Newton fluid, accompanied by the transformation of the system from particle dispersoid to emulsion. The presence of phase transition decides that the seepage regularity and plugging characteristics of petroleum resins are different from either particle dispersoid or emulsion. Herein, rheological measurements and physical model flooding experiments were performed to investigate the injection and plugging performance of petroleum resins. A correlation chart of the injection pressure, formation permeability, and the ratio of resin particle size to pore diameter is established. The dispersoid is demonstrated to present good injectivity when the ratio of the resin particle size to the pore-throat diameter of the porous media is lower than 0.35. Moreover, when the environment temperature is lower than or around the petroleum resin softening point, the injection performance of the dispersoid is not affected by temperature. Comparably, while the environment temperature is 30 °C higher than the resin softening point, the injection pressure increases due to phase transition. As indicated by the plugging experiment, the presented petroleum resin dispersoid plugging agent manifests excellent performance even in the case that the permeability of water-channeling paths is up to 20 μm², reaching a water plugging efficiency of over 85%. For water-channeling fractures with widths of 0.05–0.5 mm, the plugging pressure gradient can exceed 5 MPa m⁻¹. As suggested by combined analysis of injection and plugging performance, the disperse system should be optimized in accordance with the formation condition during field practice. Specifically, the ratio of the resin particle size to the formation pore diameter should be kept lower than 0.35, while the softening point of the petroleum resin should be 10–20 °C lower than the formation temperature.     

Effect of resin impregnation methods at the early stage of densification on the impregnation efficiency,microstructure, and thermal stability of carbon–carbon composites

The effect of impregnation methods and heat‐treatment temperature at the early stage of densification on the impregnation efficiency, microstructure, and thermal stability of carbon–carbon composites prepared from carbon–phenolic green composites was studied. The results suggest that simultaneous application of pressure and heat provides better impregnation performance during densification at the early stage of carbon–carbon composite fabrication than ultrasonic impregnation and vacuum infiltration impregnation. Also, optical microscopic examination strongly supports the result of the impregnation efficiency obtained using three different resin impregnation methods. An additional heat‐treatment at 2000 °C after carbonization results in better thermal stability and a denser microstructure of the fiber and matrix of the composite. For the carbonized composites, including a fully cured furfuryl alcohol resin impregnant, the weight loss measured by a thermogravimetric method quantitatively agrees with the weight loss occurred in a carbonization furnace at the corresponding temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 183–192, 2002     

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites: Preparation and properties

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites were prepared by the sol–gel process of tetrabutyl titanate in the presence of 4,4′‐bismaleimidodiphenyl methane modified novolak resin prepolymers with acetyl acetone as a stabilizer. These nanocomposite materials were characterized by Fourier transform infrared analysis, dynamical mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and field emission scanning electron microscopy. Nanometer titania particles were formed in the novolak resin matrix, and the average original particle size of the dispersed phase in the nanocomposites was less than 150 nm, but particle aggregates of larger size existed. The introduction of the titania inorganic phase with a nanoscale domain size did not improve the glass‐transition temperature of the nanocomposites but lowered the thermal resistance of the material because of the incomplete removal of acetyl acetone coordinated with tetrabutyl titanate, and it improved the modulus of the material at lower temperatures (<200°C) but lowered the modulus at higher temperatures (>250°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 52–57, 2006     

Preparation of high-performance epoxy-containing silicone rubber via hydrosilylation reaction

A novel epoxy-containing silicone rubber network was constructed by hydrosilylation reaction among the synthesized vinyl-containing epoxy resin prepolymers, vinyl terminated silicone oil and hydrogen-containing silicone oil. The structure of the vinyl-containing epoxy resin prepolymers was characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance spectroscopy. Morphology observations revealed that uniform “sea-island” phase separation structure was present in modified silicone rubbers. The compatibility between silicone rubber and epoxy resin was enhanced, thanks to the good dispersion of vinyl-containing epoxy prepolymers in silicone rubber matrix. The adhesion and tensile properties of modified silicone rubbers were greatly enhanced when compared with those of unmodified counterparts. The thermal degradation behavior of cured silicone rubbers was studied using thermogravimetric analysis and thermogravimetric/infrared spectrometry analysis. Results showed that the formation of epoxy-containing silicone rubber network altered the degradation process of silicone rubber, thereby yielding a higher residue at 800 °C under nitrogen atmosphere. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48397.     

含DA键自修复硅氧烷环氧树脂性能研究

将环氧氯丙烷与糠醇反应,合成糠基缩水甘油醚(FGE),再用含双烯体结构的糠胺,将环氧双封头两端连接FGE,得到端基为四元呋喃结构的中间体,与含亲双烯体结构的1,6–双马来酰亚胺基己烷(1,6–BMI)进行交联固化,得到含有Diels-Alder(DA)键的自修复硅氧烷环氧树脂(EP–DA)。通过红外分析仪、差示扫描量热仪、电子拉力试验机和热重分析仪,对EP–DA结构和性能进行了表征。研究表明:环氧双封头成功引入EP–DA体系中,DA键的正逆反应温度分别为87℃和145℃,当FGE与环氧双封头物质的量比为2∶1时,其修复率达到最大值为87.4%,同一试样经过三次修复后,其修复率仍可达41%以上。EP–DA具有较好的再加工性能,可实现EP–DA的回收再利用。     

Advanced isoconversional cure kinetic analysis of epoxy/poly(furfuryl alcohol) bio‐resin system

Furfuryl alcohol as a biomass‐derived monomer was used for synthesizing poly(furfuryl alcohol). A diglycidyl ether of bisphenol A (DGEBA) epoxy resin along with 3% and 15% by weight of the poly(furfuryl alcohol) was cured using an aliphatic amine hardener. The cure kinetics of the DGEBA/poly(furfuryl alcohol)/amine systems were investigated by nonisothermal differential scanning calorimetry. The kinetic triplets [E_α, A_α, and f(α)] were computed by using an integral isoconversional method. Based on the E_α‐dependency results a single‐step autocatalytic model was suggested for the reactions mechanism, however, the A_α‐dependency and f(α) analysis did not confirm the suggested model. Detailed kinetics analysis revealed that the cure reaction mechanism of the DGEBA did not change due to the presence of the poly(furfuryl alcohol) in the degree of conversion range < 0.75, nevertheless, it dramatically changed in the degree of conversion range > 0.75 due to the presence of 15 wt % poly(furfuryl alcohol). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45432.     

Composites of furfuryl alcohol-formaldehyde resins and olive stones for production of activated carbons

Composites based on resin of furfuryl alcohol-formaldehyde or poly(furfuryl alcohol) and olive stones (pressed and extracted as received from industrial production) were cured as small cylinders and then pyrolyzed. The pyrolysis was studied by thermogravimetric analysis up to ～? 1000°C and by FTIR-spectroscopy for the initial composites and their pyrolysis residues up to 500°C. The specific surface areas of the carbonaceous residues and their discoloring ability for dyes of methylene blue and alizarin yellow were determined. The results are interpreted and discussed under the aspects of the pyrolysis process and the new carbonaceous materials produced. The usage of olive stones in mixture with resins based on furfuryl alcohol is more advantageous (e. g. leading to higher adsorption of the dyes) than the usage of the resin alone.     

Toxic metal ion removal by terpolymer ion-exchanger from aqueous environments: synthesis,thermal degradation,batch separation,kinetic and isotherm studies

A novel chelating resin was synthesized and characterized by elemental, physico-chemical, GPC, NMR, and SEM analyses. Batch separation was adopted to study the recovery of selected metal ions with respect to the pH, time, concentrations, and electrolytes. From the results, it was observed that the order of the rate of metal ion uptake by the resin was Fe³⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺ > Co²⁺ > Pb²⁺ ions. The adsorption kinetics follows first order, and isotherm models were also found to fit each other. The resin showed three-step thermal degradation, and its kinetic and thermodynamic parameters were also evaluated.     

改性海泡石和γ-Al_2O_3负载Ni-B-Mo合金催化糠醛液相加氢制糠醇

分别以改性海泡石(Sep)和γ-Al2O3为载体,采用浸渍还原法制备了负载型Ni-B-Mo合金催化剂,用于催化糠醛液相加氢。研究发现,Ni-B-Mo/Sep催化剂上糠醛转化率为83.8%、糠醇的选择性为98.7%,均优于Ni-B-Mo/γ-Al2O3。采用差热分析(DTA)、NH3吸附红外光谱(IR)、比表面积测试(BET)和程序升温脱附(TPD)等技术,考察了载体对Ni-B-Mo合金催化剂性能的影响。研究结果表明,Ni-B-Mo/Sep表现出高活性主要是由于其独特的合金组成、较高的Ni含量和L酸中心、对反应物中等强度的吸附中心变弱以及吸附中心数目增多、具有更少的吸附产物中心所致。Ni-B-Mo/Sep选择性更高主要是由于其对糠醇吸附的强度较弱,不易发生深度加氢。     

Synthesis and characterization of epoxidized phenolic novolacs modified by furfuryl alcohol

The possibility of reacting furfuryl alcohol with the p-position of phenolic rings, under acid conditions, was proved using different experimental techniques: size exclusion chromatography, Fourier transform infrared spectroscopy and ¹³C NMR. This reaction was then used in the modification of phenolic novolacs with furfuryl alcohol. After reaction with epichlorohydrin, epoxidized phenolic novolacs (EPN) modified with furan rings were obtained. They could be cured with aromatic diamines in a similar way to conventional EPNs. The presence of furan rings should improve burning resistance and smoke emission characteristics of the resulting networks.     

Fe3O4/poly(acrylic acid) hybrid nanoparticles for water‐based drilling fluids

Because of the sizes of the pore throat are on the nanometer scale, nanoparticles with sizes on the nanoscale have been developed as candidates for plugging materials during drilling in shale formation. In this study, Fe₃O₄ nanoparticles were prepared by a coprecipitation method, and then, Fe₃O₄/poly(acrylic acid) (PAA) hybrid nanoparticles were obtained through the modification of the Fe₃O₄ nanoparticles with PAA. The hybrid nanoparticles were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The magnetic properties, salt tolerance, and compatibility with sulfomethylated phenolic resin of the nanoparticles were studied. The plugging properties of the Fe₃O₄/PAA hybrid nanoparticles were evaluated by filtration testing of the filter cakes at ambient temperature and 80 °C. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43967.     

新型糠酮树脂的研究

改性糠酮树脂是由环己酮、尿素、甲醛和糠醇缩合而成的新型铸造用的呋喃树脂。其反应分三步,第一步是酮醛树脂的合成,第二步是脲醛树脂的合成,第三步是糠酮树脂的缩聚,制得改性糠酮呋喃树脂,其具有光泽好、硬度高、附着力好、铸造时表面光滑容易脱模,且生产成本低、合成工艺简单、耐酸耐碱性能好等优点。本文介绍了该树脂的合成方法及合成工艺条件的选择与确定,及其最佳固化剂量和固化时间的确定。     

Synthesis and properties of self-healing hydrogel plugging agent

The P(AM-co-AMPS)/SA DN hydrogel was synthesized through aqueous polymerization in this study. It formed a crosslinking network with hydrophobic associations between acrylamide (AM) and lauryl methacrylate (LMA), as well as an ionic bond network involving sodium alginate and Ca²⁺. To enhance its high-temperature resistance, 2-acrylamide-2-methylpropane sulfonic acid (AMPS) was incorporated into the hydrogel formulation. The structure of the hydrogel was characterized using Fourier transform infrared spectrometer (FTIR), thermogravimetric analyzer (TGA), and scanning electron microscopy (SEM) techniques. Results demonstrated that the hydrogel exhibited excellent temperature resistance and possessed a porous structure. Mechanical testing revealed a high tensile strength of 110 kPa, elongation at break of 995.31%, along with good fatigue resistance and self-recovery performance during multiple cyclic stretching. Healing experiments indicated that the healing strength of the hydrogel was influenced by temperature variations. Furthermore, pressure plugging tests were conducted on steel models with crack widths of 0.5 and 1 mm, respectively; it was found that the 0.8%P(AM-co-AMPS)/SA DN hydrogel could withstand pressures up to 4.5 MPa at a temperature of 70°C. This novel hydrogel material exhibits remarkable mechanical properties along with certain self-healing capabilities, making it suitable for leak control applications.     

Mechanical and thermal properties of graphene oxide/phenolic resin composite

In this article, samples of phenolic resin reinforced with graphene oxide were prepared. Mechanical properties of the composite were tested. Dynamic mechanical analysis, Fourier transform infrared spectroscopy, Differential scanning calorimetry, and thermogravimetric analysis were employed to study the mechanical properties in varied temperatures to infer the influence of graphene oxide on thermal performance of phenolic resin. The results show that the addition of graphene oxide resulted in a significant improvement in the elastic modulus of phenolic resin; Young's modulus, and tensile strength increase along with the graphene oxide content. Esterification reaction happened between alcohol  OH groups on resole and carbonyl (sbond]COOH) groups on graphene oxide. Addition of graphene oxide improved residue rate of phenolic resin by 5.8%, whereas the temperature distribution of phenolic pyrolysis stay unchanged. The glass transition temperature of phenolic resin has been improved by 30°C. POLYM. COMPOS. 34:1245–1249, 2013. © 2013 Society of Plastics Engineers