Resin Acids Research Articles

Influence of wood pretreatment, hardwood and softwood extractives on the compressive strength of fly ash-based geopolymer composite

This paper investigated the specific compressive strength (specific strength) of fly ash-based geopolymer composites with four hardwood extractives and two softwood extractives, as well as specific wood extractives. Additionally, the effect of the portion of pine wood (i.e., sapwood and heartwood) and wood pretreatment with NaOH were considered. Geopolymer paste (with extractives) and geopolymer wood composites (GWCs) were cured at 60 °C for 24 h. The samples were stored in a climate chamber (20 °C, 65% RH) for 7 days before finally testing under compression. From the results, the specific strengths of geopolymers with hardwood extractives were not significantly affected. However, geopolymers containing pine extractives showed the most significant reduction in specific strength. There were no significant differences in the specific strengths of geopolymers containing polyphenols and resin acid. Generally, geopolymers containing fatty acids recorded the lowest specific strengths. There was no difference between the GWCs with untreated sapwood and heartwood. However, the wood pretreatment led to a 21% and 10% increase in the specific strengths of GWCs with sapwood and heartwood, respectively. The findings of this study form the basis for improved GWCs production and a wide range of applications for green composite materials.

Energy-Consumption-Based Life Cycle Assessment of Additive-Manufactured Product with Different Types of Materials.

Additive manufacturing (AM) or 3D printing technology is one of the preferred methods to ensure sustainability in fabrication. In addition to providing continuity in sustainability, fabrication, and diversity, it aims to improve people's quality of life, develop the economy, and protect the environment and resources for future generations. In this study, the life cycle assessment (LCA) method was used to determine whether a product fabricated by the AM provides tangible benefits compared to traditional fabrication methodologies. LCA is an evaluation method that provides information on resource efficiency and waste generation, where the environmental impacts of a process can be calculated, measured, and reported throughout the entire life cycle, starting from the acquisition of raw materials, processing, fabrication, use, end of life, and disposal, according to ISO 14040/44 standards. This study examines the environmental impacts of the three most preferred filaments and resin materials in the AM for a 3D-printed product from the start, which consists of three stages. These stages are raw material extraction, manufacturing, and recycling. Filament material types are Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), Polyethylene Terephthalate (PETG), and Ultraviolet (UV) Resin. The fabrication process was carried out with Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques using a 3D printer. Environmental impacts for all identified steps were estimated over the life cycle using the energy consumption model. As a result of the LCA, it was seen that UV Resin was the most environmentally friendly material in the mid-point and end-point indicators. It has been determined that the ABS material also exhibits bad results on many indicators and is the least environmentally friendly. The results support those working with AM in comparing different materials' environmental impacts and choosing an environmentally friendly material.

Novel superhydrophobic core-shell fibers/epoxy coatings with self-healing anti-corrosion properties in both acidic and alkaline environments

In this study, a self-healing coating with inherent properties of superhydrophobicity and pH-responsibility is introduced through encapsulation of oleic acid and epoxy resin in cellulose acetate nanofibers by electrospinning method, followed by applying a layer of epoxy coating modified with both polydimethylsiloxane and SiO2 nanoparticles. The prepared core-shell fibers/epoxy coating has a static contact angle of 157.3 ± 3° with sliding angle of 3.5 ± 0.5°, while the electrochemical impedance spectroscopy results demonstrate that the self-healing rate of the scratched core-shell fibers/epoxy coating is 55.65 and 87.10 kΩ cm2 d−1 after 4 and 12 days soaking in the 3.5 wt% NaCl solution with pH = 12.0 and 4.0, respectively. According to the results of the electrochemical impedance spectroscopy, the corrosion resistance of the core-shell fibers/epoxy coating is remarkably more than the coating without fibers, and the coating with fibers exhibits a significant self-healing performance, excellent wear resistance, and chemical stability. This study would extend the application of the electrospinning technology in the field of superhydrophobic anti-corrosive coatings.

Eco friendly synthesis of epoxidized palm oleic acid in acidic ion exchange resin

Abstract Global raw material use has moved from a non-renewable to a renewable resource. Additionally, the research on epoxidation has produced a safer, more cost-effective, and ecologically friendly product than non-renewable resources. At present, there are limited studies on the production of epoxidized palm oleic acid using eco-friendly ion exchange resin method. Consequently, the objective of this study is to optimise the reaction conditions of epoxidation palm oleic acid using ion exchange resin (amberlite IR 120H) as a catalyst. Epoxidized palm oleic acid was prepared using performic acid formed in situ by mixing formic acid with hydrogen peroxide. The results showed that the optimum reaction conditions for the production of oxirane content were a temperature of 75 °C and a hydrogen peroxide concentration of 30%. The maximum relative conversion of palm oleic acid to oxirane was achieved using the optimum conditions with up to 75%. Finally, a mathematical model was developed using MATLAB and the fourth-order Runge–Kutta method was integrated with the genetic algorithm to determine the reaction rate, which was consistent with the experimental data. This study proved that palm oleic acid was successfully converted into a green epoxide that promotes the use of palm oil as a raw material.

Preparation and Performance of a Self-Produced High-Molecular-Weight Waterborne Epoxy–Acrylic Emulsion

To improve the stability of waterborne epoxy–acrylic emulsions and their comprehensive properties, such as the chemical resistance of coatings, a new research idea is proposed in this paper. First, a series of high-molecular-weight epoxy resins were synthesized with epoxy resin E-51 and bisphenol A (BPA) using benzyl triphenyl phosphine bromide as the catalyst. Then, free-radical graft copolymerization was carried out between the epoxy resin and methacrylic acid (MAA), styrene (ST), and butyl acrylate (BA) using benzoyl peroxide (BPO) as the initiator. This method ensured that the epoxy groups were retained. Finally, the carboxylic acid groups were neutralized with N,N-dimethylethanolamine (DMEA), and a stable aqueous epoxy–acrylic emulsion was obtained by high-speed dispersion in deionized water. The effects of key factors such as temperature, time, the molecular weight and dosage of epoxy resin, the dosage of MAA, the dosage of BPO, and the neutralization degree of the synthesis of emulsions and coating film properties were mainly discussed. The molecular weight and molecular weight distribution of the epoxy resin were determined by gel permeation chromatography (GPC). The epoxy resin and its graft copolymer were analyzed and characterized by Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The particle size and distribution of the emulsions were tested by laser particle size analysis. The morphology of the emulsion particles was observed by transmission electron microscopy. The results showed that the acrylic monomers (MAA, ST, and BA) were grafted onto the epoxy resin. The graft copolymers showed higher glass transition temperatures compared with those of the pure epoxy resin. TGA showed that the graft copolymer started to decompose at a high temperature before the pure epoxy resin did, and the thermal stability was slightly reduced. The prepared emulsions with a particle size of 160 nm had a storage stability of more than one year and showed excellent dilution stability, mechanical stability, and freeze–thaw stability. The emulsions were coated and cured at 150 °C for 1 h with a pencil hardness of 5 H, an adhesion of grade 1, and a flexibility of 1 mm. The water resistance was >60 days, the salt water resistance was >30 days, the acid resistance was >10 days, and the alkali resistance was >5 days.

Evaluation of the resistance of adhesive joints of carpentry to atmospheric fluctuations

Wood and wooden glued products are widely used as building structures in various construction industries that operate within a wide range of atmospheric factors and require stability and durability. Therefore, the goal was to conduct experimental studies to determine the stability of the adhesive bond of a window element made of wood under the influence of temperature and moisture static fluctuations. In this regard, a comprehensive approach was applied to experimentally establish the effectiveness of the glued wood layer by investigating the resistance of the adhesive layer to destruction when changing temperature and humidity fields within a wide range. According to the experimental values of the adhesive layer boundary after exposure to temperature and humidity fields such as glued wood, it was established that the best result of the tensile strength (0.29 N/mm2) was obtained for polyurethane adhesive. For rubber glue and PVA, the tensile strength was 0.17 N/mm2, which provides adhesion quite well due to its properties. This is due to the fact that the adhesive composition must have sufficient elasticity to allow the wood to expand and dry out under the influence of temperature. In turn, the glued layer based on bustilate and liquid glass, has the tensile strength set at a preasure of 0.07 N/mm2 and 0.12 N/mm2 accordingly. A decrease in the adhesive capacity for bustilate is due to the fact that at a low-temperature level, it loses its properties. The liquid glass-based adhesive has an alkaline environment and interacts with the components of wood resin acids, reducing adhesion. The results obtained allow selecting effective adhesives for the production of composite materials from wood, depending on the operating conditions, and provide for the properties of glued wood

Heterogeneous Catalytic Conversion of Terpenes into Biofuels: An Open Pathway to Sustainable Fuels

The production and use of terpene-based fuels represents a renewable source of energy in the transportation sector, especially in the aviation sector. The literature on the conversion of terpenes into valuable compounds is not new but has been based on the production of products for cosmetics and pharmaceutics. Several established chemical routes are also a way to develop drop-in fuels. The present work explores all the main chemical processes that can transform terpenes into more valuable fuels or additives, focusing on the use of heterogeneous catalysis, catalyst type, operating conditions, and reaction performance. α-pinene is the most studied catalyst, since it is the main component of turpentine. Isomerization is the most frequently applied chemical pathway used to enhance fuel properties, and a wide group of heterogeneous catalysts have been reported, with sulphonic acid resin catalysts, transition metals, alumina, and silicates being the most used. This work also explores the current production and commercialization of terpenes, as well as the challenges for their use as fuels at a commercial scale. The future challenge is to discover new catalysts or to improve the performance of the current products and reduce production costs. The feasibility of the production and commercialization of terpene-derived fuels is also linked to oil prices.

An Economical Composite Membrane with High Ion Selectivity for Vanadium Flow Batteries.

The ion exchange membrane of the Nafion series widely used in vanadium flow batteries (VFBs) is characterized by its high cost and high vanadium permeability, which limit the further commercialization of VFBs. Herein, a thin composite membrane enabled by a low-cost microporous polyethylene (PE) substrate and perfluorosulfonic acid (PFSA) resin is proposed to reduce the cost of the membrane. Meanwhile, the rigid PE substrate limits the swelling of the composite membrane, which effectively reduces the penetration of vanadium ions and improves the ion selectivity of the composite membrane. Benefiting from such a rational design, a VFB assembled with the PE/PFSA composite membrane exhibited a higher coulombic efficiency (CE ≈ 96.8%) compared with commercial Nafion212 at 200 mA cm-2. Significantly, the energy efficiency maintained stability within 200 cycles with a slow decay rate. In practical terms, the thin PE/PFSA composite membrane with low cost and high ion selectivity can make an ideal membrane candidate in VFBs.

Preparation and mechanical properties of plain jute rope fabric reinforced polylactic acid composites

The biodegradable natural jute threads (JT) were braided into jute flag ropes (JFR) by a flag braiding machine first. Then, JT and JFR were woven into plain-woven jute thread fabrics (JTF) and jute flag rope fabrics (JFRF), respectively, by using a dobby loom. Subsequently, JTF and JFRF were impregnated with polylactic acid (PLA) resin to become JTF/PLA and JFRF/PLA composites, respectively. These JTF/PLA and JFRF/PLA composites are biodegradable. The tensile, compressive, and bending characteristics of these composites were examined by a material test system (MTS 810). In addition, the impact properties of these composites were evaluated by an Izod tester. The experimental results show that the braiding technique strengthened the jute ropes. The JFRF/PLA composite has high tensile strength, compressive modulus, bending modulus, and impact resistance

Determination of β2-Agonist Residues in Fermented Ham Using UHPLC-MS/MS after Enzymatic Digestion and Sulfonic Resin Solid Phase Purification

β2-agonists are a class of synthetic sympathomimetic drugs with acute poisoning effects if consumed as residues in foods. To improve the efficiency of sample preparation and to overcome matrix-dependent signal suppression in the quantitative analysis of four β2-agonists (clenbuterol, ractopamine, salbutamol, and terbutaline) residues in fermented ham, an enzyme digestion coupled cation exchange purification method for sample preparation was established using ultra-high performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS). Enzymatic digests were subject to cleanup treatment on three different solid phase extraction (SPE) columns and a polymer-based strong cation resin (SCR) cartridge containing sulfonic resin was found to be optimal compared with silica-based sulfonic acid and polymer sulfonic acid resins based SPEs. The analytes were investigated over the linear range of 0.5 to 10.0 μg/kg with recovery rates of 76.0-102.0%, and a relative standard deviation of 1.8-13.3% (n = 6). The limit of detection (LOD) and the limit of quantification (LOQ) were 0.1 μg/kg and 0.3 μg/kg, respectively. This newly developed method was applied to the detection of β2-agonist residues in 50 commercial ham products and only one sample was found to contain β2-agonist residues (clenbuterol at 15.2 µg/kg).

Biodegradable thermoset poly(lactic acid) resin containing phosphorus: Flame retardancy, mechanical properties and its soil degradation behavior

With the growing environmental awareness, poly(lactic acid) (PLA) is regarded as one of the most promising varieties of bio-based polyesters owing to its environment-friendly and biodegradable advantages. However, poor thermal stability and flammability disadvantages limit the applications of PLA. Herein, a series of biodegradable intrinsic flame-retardant thermoset PLA resins (DMMP-M4sPLA) were designed. DMMP-M4sPLA resins exhibit excellent flame retardancy, achieving UL 94 V-0 rating and limiting oxygen index (LOI) of 28.1 %–31.7 %. Meanwhile, the cured DMMP-M4sPLA resins show a high glass transition temperature and tensile strength. In addition, the resins demonstrate full degradation with no harmful degradation products. This work provides an advanced design strategy to create bio-based and biodegraded resins with superior flame retardant and mechanical performance, holding great potentials in the fields of aviation interior, automotive, etc.

Resin acids play key roles in shaping microbial communities during initial degradation of spruce bark

Resin acids play key roles in shaping microbial communities during initial degradation of spruce bark

Single‐walled Carbon Nanotubes Dispersed by CO2 Responsive Surfactants for Fabricating High Conductive Epoxy Composites

AbstractThe emerging nanomaterials single‐walled carbon nanotube (SWNTs) with large specific surface area, excellent electrical conductivity and high mechanical strength, has been used to fabricate electronic devices. However, the extremely strong π‐π interactions make SWNTs easy to agglomerate, thus limiting their application. In this work, a novel method was applied to disperse SWNTs by using rigid rosin‐based CO2 responsive surfactant rosin acid dimaleimide choline (R‐BMI‐C). When pH 10.4, SWNTs can be uniformly and stably dispersed, and at pH 6.3, SWNTs aggregated. The dispersed SWNTs was then integrated into diglycidyl ether of bis phenol A (DGEBA) to fabricate high conductive epoxy composites. Their properties were characterized by SEM, TG, high resistivity meters, etc.. The results showed that the modified SWNTs/DGEBA composites obtained an ultra‐low percolation threshold (0.025 wt.%). Compared with the original SWNTs/DGEBA composite, its tensile strength and elastic modulus were enhanced by 17 % and 96 %, respectively, when the SWNTs content was 0.5 wt.%.

Potassium channel openers targeting different sites of the channel.

Voltage-gated ion channels play essential roles in generating and shaping the electrical excitability of nerve and heart cells. Mutations in these ion channels can cause diseases, which can be treated with pharmaceuticals targeting specific ion channels. While many pharmaceuticals cause their effects by blocking the ion-conducting pore to prevent the ion current, only a few exert their therapeutic effect by opening (or activating) the channel. While they see limited use as pharmaceuticals at present, recent research has identified many different types of compounds that can open ion channels. Here, I will present data from three classes of compounds capable of opening voltage-gated potassium (Kv) channels. (1) The first class includes resin acids and polyunsaturated fatty acids. These negatively charged compounds have close interactions with the channel's positively charged voltage sensor, opening the channel by pulling the sensor to an activated position. This interaction occurs at the interface between the phospholipid bilayer and the channel protein. (2) Biaryl sulfonamide acids can access the voltage sensor through the extracellular space, allowing them to activate the Kv1-like Shaker channel. (3) Warfarine-like tautomers activate Kv1.5 channels via close interactions with the linker connecting the voltage sensor and the channel's ion conducting pore domain. Characterizing different binding sites and compounds that use them on different ion channels will hopefully lead to better treatments for diseases caused by altered excitability.

Gas Porosity Defect – What It Means and How to Respond

The foundries are facing problem-related to the selection of the parameter’s value for minimum rejection and maximum productivity. The furan no-bake binders system guaranteed dimensional stability and a comparative good surface finish of the casting. Based on past data in the industry, it is found that gas porosity defect is one of the highest. The phenomenon of the formation of the bubble in the fissures of the mould-metal interface, and later on trapping during the solidification leads to gas porosity. The current research work is focused on the minimization of the defect by the selection of the optimum range of input variables. Based on rigorous literature survey and industrial expert’s opinion, it is found that the parameters like grain fineness number (GFN) of the sand, loss on ignition (LoI) of the used sand, the sand temperature at the mixing time, potential of hydrogen (pH) are important parameters for gas porosity defect in the casting.Design-Expert software and particularly response surface methodology (RSM) and sequential approach using the face-centered central composite design is used for the experiments. The results show that a quadratic model with the removal of some insignificant term is a comparatively best fit for gas porosity defects. After analysis, various favorable levels of different parameters are obtained. The research work is based on realistic problems of the foundries and based on the experimental work. Thus, the provided solution is very much useful for foundries to reduce the rejection, particularly for furan no-bake with furfuryl alcohol as resin and sulphonic acid as catalyst. The research problem addressed in the paper is a genuine problem of the foundries and the sole work is based on experimental evidence.

Blown film stability for low, medium, and high molecular weight polylactic acid and their tensile properties

Three poly (lactic acid) (PLA) resins with molecular weight (Mw) equal to 55 (3251D), 125 (L105) and 163 (LX175) kg/mol were characterized in terms of capillary viscosity, mechanical and thermal properties and used to produce blown films. The effect of temperature, extrusion rate, stretching (TUR) and blow-up (BUR) ratios were evaluated to determine the optimum processing conditions for blown films based on the bubble stability and to determine their final tensile properties. As expected, the processing temperature was the most critical parameter on the film stability. The lower Mw PLA showed limited processing stability. Stable conditions were found at higher temperature (200°C) for higher Mw. These results correlate with the PLA viscosity (melt strength). Finally, the PLA film tensile strength (TS) strongly depended on their processability. For example, 3251D and L105 required high stretching (TUR = 3.4 and 7) for maximum TS (30 and 64 MPa) with a low blow-up ratio (BUR = 1.02–1.15). However, a moderate increase in BUR (10% at TUR = 3) led to a substantial drop in TS (from 29 MPa to 21 MPa for PLA 3251D and 44 MPa–34 MPa for L105). Overall, LX175 was the most interesting resin with 49 MPa TS which was independent of the BUR and TUR used in this investigation.

Thermochemical recycling of tall oil pitch in a dual fluidized bed

Crude tall oil is a by-product obtained from the manufacture of chemical wood pulp. The residue obtained after the distillation of this product is known as tall oil pitch (TOP). This complex fraction is a highly viscous liquid that consists mainly of free fatty acids, fatty acids derivatives, rosin acids and additives. Given its complex composition, it is commonly used as fuel for heat production. In this work, steam cracking is proposed as an alternative treatment for this residue. Steam cracking can convert TOP into a valuable product gas that can be used in different applications including the production of green chemicals, moving towards a carbon circular economy. The experimental tests were performed in the Chalmers pilot scale Dual Fluidized Bed, consisting of a steam cracker and a combustor. For these experiments, the thermochemical decomposition of 150–175 kg/h TOP was performed at the steam cracker at two different temperatures (775 and 825 °C) to evaluate the influence of this parameter on the obtained products. Wood pellets were also tested as reference material for the highest temperature. The distribution of the obtained products was analysed. Results show that TOP can be regarded as a by-product instead of a residue and used as feedstock for the recovery of chemical building blocks and syngas via thermochemical recycling. Between 40 and 50 % of the carbon present in the fuel is kept in the permanent gases, while about 20 % is in aromatic hydrocarbons. Compared to biomass, the aromatics yield obtained for TOP is much higher (190 g/kg for TOP and 13 g/kg for biomass). Among the species found, benzene, toluene and xylene, represent between 62 and 72 % of the total measured aromatics. Regarding the gas fraction, the production of valuable light hydrocarbons (such as ethylene and propylene) is more pronounced in the TOP residue than in the biomass. In addition, an energy balance over the system was estimated and showed that TOP thermochemical recycling can be self-sustained in a Dual Fluidized Bed if the non-valuable products are combusted. The results obtained in this work indicate that this TOP could be an appealing option to consider as a source of biorefinery revenue leading to the circular use of waste.

From lab-scale to pilot-scale treatment of real wastewater from the production of rayon fiber

The subject of our study involved the treatment of real process wastewater from the production of rayon fiber. During the annual monitoring of the production facility, we performed a mass balance of three problematic sources of process wastewater and analyzed them repeatedly. All three sources showed high values of COD = 0.4–30 g/L, TOC = 0.09–7.1 g/L and the concentration of Zn2+ 0.09–0.5 g/L. At a total volume of 1.84 million m3, this represents a significant pollution source for the Elbe River. At lab-scale, we tested a combination of filtration, microfiltration, and oxidation using the Fenton, electro-assisted Fenton, and the electrochemical oxidation methods, both on the plate and newly developed macroporous BDD electrodes on a ceramic substrate, along with the final adsorption of Zn2+ emissions on the strongly acidic cation exchange resin Lewatit Mono plus S108. It was tested in Na+ and H+ cycles. Using an optimized technological sequence, we have achieved a COD reduction of up to 98%, and a TOC reduction of 85%. During the H+ cycle cation regeneration by sulfuric acid, Zn2+ emissions were converted to zinc sulfate that can be recycled in the spinning bath of the production process. The method was verified at a pilot scale.

Stepwise modification with 2,3-epoxypropyltrimethylammonium chloride cationization and rosin acid impregnation to improve water repellency and mold-proof property of bamboo

As its abundant reserves and good physical properties, bamboo is deemed to be a promising feedstock material for construction and home furnishing. However, the hydrophilicity of bamboo and its rich nutrients make it susceptible to mold infection. In this study, bamboo firstly reacted with 0, 3, 6, 9, and 12 wt times of 2,3-epoxy-propyltrimethylammonium chloride (EPTAC) in NaOH/Urea solution, respectively, and then impregnated with rosin acid. Effects of modification on structure, thermal stability and water repellency of bamboo were identified by FT-IR, XRD, XPS, SEM, TGA, contact angle measurement and water absorption coefficient, respectively. A comparative study of mold-proof properties of original and modified bamboo was conducted as inoculation of Aspergillus niger, Penicillium citrinum and Trichoderma viride on samples. The results indicated that the sample obtained from a mass ratio (EPTAC to bamboo) of 9 had the highest substitution degree, charge content and ion exchange capacity as compared to samples obtained from other EPTAC dosages. After modification, the density of bamboo increased by 43.3%, which exhibited considerable thermal stability. Impregnating this sample with rosin acid improved its water-repelling and anti-swelling efficiency to 10.91% and 27.83%, respectively. Compared with the original bamboo, anti-mold property of EPTAC modified bamboo to three fungi was notably improved and achieved rate 1 mold coverings. Impregnation-modified bamboo with rosin acid enhanced the anti-mold property, achieving a rate of 0 mold covering. The research provides a feasible way to improve the mildew resistance of bamboo and promote the utilization of rosin.

Synthesis of Vinyl–Trivinyl Acidic Resins for Application in Catalysis: Statistical Study and Site Accessibility Assessment

This study aimed to synthesize sulfonated polymer resins based on styrene and trimethylolpropane triacrylate (TMPTA) and evaluate their catalytic efficiency in glycerol acetylation. A factorial design was used, with two factors, three levels, and three replicates of the center point. The factors were cross-linker percentage (YTMPTA) and cross-linker feed time (TTMPTA). Ion-exchange capacity, swelling index, and catalytic efficiency were analyzed to characterize each resin. Lower cross-linker percentages resulted in higher catalytic efficiencies, as expected. Resins synthesized with 2, 6, and 10% TMPTA had mean catalytic efficiencies of 215, 176, and 121, respectively. A linear correlation was observed between catalytic efficiency and cross-linker percentage, with R2 = 0.9971. Statistical and kinetic models were developed to represent the experimental results and support the development of strategies to improve resin formulation and synthesis conditions. TMPTA feed time at low and high levels positively influenced catalytic efficiency; the result is attributed to the micro- and macrostructure of resins. This finding was corroborated by the kinetic constants provided by the model.