Solid Resin Research Articles

Scalable membrane-assisted ion exchange (MEM-IE) strategy for organic acid purification in biorefinery process

The transition towards a carbon-neutral society necessitates radical approaches in the bio-refinery pipeline, particularly in the production of organic acids. The current downstream process from a dilute fermentation broth is limited by the extensive use of acids and bases, along with heavy reliance on energy-intensive distillation. In this work, we propose an entirely membrane-based process to purify organic acids (e.g., gluconic acid) from a crude solution of catalytic dehydrogenation of glucose. To facilitate downstream purification, we introduce an innovative membrane-assisted ion exchange (MEM-IE) strategy, which is a scalable process that can protonate ionic compounds entirely in the solution phase. Instead of a solid ion exchange resin, a bulky yet soluble acidification agent is used to protonate the target compound, which can be easily separated via a size exclusion membrane. We selected non-toxic poly (4-styrene sulfonic acid) (H-PSS, 75 kDa) as the acidification agent to selectively protonate gluconate ions and to enable facile fractionation. The proposed MEM-IE strategy can overcome the scale-up limitation of traditional solid ion exchange resins and can be applied to many types of ionic compounds. The versatility of the proposed process was also demonstrated on formate and lactate compounds. A techno-economic evaluation using the Verberne cost model showed that the proposed process achieves an 80 % reduction in energy consumption compared to the fermentation-based process, and the return on investment (ROI) of a 330 ton-per-day plant was less than a year. The proposed membrane-based process for the purification of organic acids, particularly the MEM-IE strategy, offers a sustainable and energy-efficient downstream separation platform.

Wear Performance Evaluation of Polymer Overlays on Engine Bearings.

Modern engine bearing materials encounter the challenge of functioning under conditions of mixed lubrication, low viscosity oils, downsizing, start-stop engines, potentially leading to metal-to-metal contact and, subsequently, premature bearing failure. In this work, two types of polymer overlays were applied to the bearing surface to compensate for extreme conditions, such as excessive loads and mixed lubrication. Two different polymer overlays, created through a curing process on a conventional engine bearing surface with an approximate thickness of 13 µm, were investigated for their friction and wear resistances under a 30 N load using a pin-on-disc setup. The results indicate that the newly developed polymer overlay (NDP, PAI-based coating) surface has a coefficient of friction (COF) of 0.155 and a wear volume loss of 0.010 cm3. In contrast, the currently used polymer overlay (CPO) in this field shows higher values with a COF of 0.378 and a wear volume loss of 0.024 cm3, which is significantly greater than that of the NDP. It was found that, in addition to accurately selecting the ratios of solid lubricants, polymer resins, and wear-resistant hard particle additives (metal powders, metal oxides, carbides, etc.) within the polymer coating, the effective presence of a transfer film providing low friction on the counter surface also played a crucial role.

Species-Specific quantification of bioactive boswellic acids in Boswellia resin using NIR spectroscopy, HPLC and Multivariate data analysis

The bioactive compounds Acetyl-11-keto-β-boswellic acid (AKBA) and 11-keto-β-boswellic acid (KBA), found in the resin of the Boswellia tree, exhibit anti-inflammatory properties, rendering Boswellia resin an intriguing natural medicinal products. However, the content of boswellic acids varies across different Boswellia species and proper knowledge of its species-dependent nature, as well as alternatives to the resource- and time-intensive HPLC analysis, are lacking. Here we present a comprehensive investigation into the boswellic acid content of seven Boswellia species from ten countries and introduce a novel and non-destructive Near-Infrared spectroscopy method for predicting boswellic acid concentrations in solid resin samples. The HPLC-UV reference analysis revealed AKBA concentrations of up to 7.27 % (w/w) with KBA concentrations reaching up to 1.28 % (w/w). Principal Component Analysis of the HPLC and NIR spectroscopy data unveiled species-specific variations, facilitating differentiation based on boswellic acid content, characteristic chromatograms and NIR spectra. Using the HPLC-UV quantification as reference, we developed a Partial Least Squares regression model based on NIR spectra of the resin samples. This model demonstrated highly satisfactory predictive capabilities for AKBA content, achieving a root mean square error of prediction of 0.74 % (w/w) and an R2val of 0.79 in independent test set validation. Although the model was less effective for predicting KBA content, it still offered valuable estimates. The spectroscopic method introduced in this study provides a cost-effective and solvent-free approach for predicting boswellic acid content, demonstrating the potential for application in non-laboratory settings through the use of miniaturized NIR spectrometers. Consequently, this method aligns well with the principles of green chemistry and addresses the growing demand for alternative analytical techniques.

Continuous kinetics of 2-hydroxyisobutryic acid esterification using solid acid granular and monolithic activated carbon catalysts

Kinetics of 2-hydroxyisobutyric acid (2-HIBA) esterification with ethanol was studied using sulfonated carbon catalysts in granular (sGAC) and monolith (sACM) forms in a continuous flow packed bed reactor. 2-HIBA is a potential biobased carboxylic acid and its ester a sustainably produced industrial solvent. The catalyst monolith form, made from renewable carbon, offers significantly higher space time yields and conversions, yet little kinetic data or models are available for its use, especially under non-ideal conditions. The effect of ethanol/2-HIBA molar ratio (44, 10, 3.6 and 1.5) at different liquid residence times (3–9 min) was investigated using sGAC. Kinetics of sACM esterifications were investigated at a molar ratio of 3.6 by varying the residence time (2–7 min) and compared with the sGAC. The sACM displayed higher ester yields, acid conversions, and significantly higher reaction rates and space–time-yields (2.1–2.8 ×) compared to the sGAC due to higher surface area to volume ratio. The sACM reaction rates and turnover frequency were comparable to solid acid resins and sulfated silica and zirconia. Pseudo-homogeneous, Eley-Rideal and Langmuir-Hinshelwood models were applied to fit the kinetic data, and the reaction system parameters were obtained through regression analysis. The LH dual active site model resulted in the lowest mean relative error for both 2-HIBA and ester concentration residuals. Adsorption/desorption equilibrium constants for 2-HIBA, ethanol, and ester, were higher compared to water suggesting hydrophobic regions in the sGAC/sACM. Estimation of the external and internal mass transfer criteria indicated negligible effects of mass transfer. With further development sACM and the kinetic model can be used for reactor design of continuous esterification processes using solid acid monolith catalysts.

Terahertz spectral characteristics of photosensitive resin based on microfluidic technology

Photosensitive resin is a kind of polymer gel material. Due to its excellent UV curing performance, it is widely used in the emerging 3D printing industry. This article combines terahertz technology with microfluidic chip technology to study the terahertz spectral characteristics of liquid and solid photosensitive resins under different electric fields. In the experiment, it was found that an electric field can also cause polymerization of photosensitive resin monomers to form cross-linked polymers, increasing their curing degree. For solid photosensitive resins, the orientation of polymer molecules is enhanced under an electric field, and the molecular arrangement changes from a disordered state to an ordered state. Meanwhile, it was found that both liquid and solid photosensitive resins subjected to electric fields exhibit absorption coefficients below zero within a very small frequency range. We explain this from two aspects: energy and the Fabry Pérot effect. This article uses terahertz spectra to study the curing and structural changes in photosensitive resins under an electric field, laying a foundation for further improving 3D printing technology.

Experimental study on the effect of Coumarone resin on the performance of SBS-modified asphalt.

An inexpensive and high-performing solid Coumarone resin was added to Styrene-butadiene-styrene (SBS) copolymer-modified asphalt to enhance its storage stability and road performance. To assess the effect of Coumarone resin dosage on the SBS-modified asphalt, a series of laboratory tests were conducted. The composite modified asphalt's segregation test was used to evaluate its storage stability, Dynamic Shear Rheometer (DSR) and Multiple Stress Creep Recovery (MSCR) tests were employed to investigate its high-temperature performance and permanent deformation resistance, and the Bending Beam Rheology (BBR) test was utilized to measure its low-temperature performance. Fluorescence microscopy was used to observe the composite modified asphalt's microstructure, and Fourier Transform Infrared Spectroscopy (FTIR) was conducted to study the changes in chemical structure during the modification process. The results showed that Coumarone resin can improve the compatibility of SBS and asphalt, improve the high-temperature performance and deformation resistance of SBS-modified asphalt, and adding an appropriate amount of Coumarone resin can help enhance the low-temperature cracking resistance of modified asphalt. The optimal dosage of Coumarone resin recommended for SBS-modified asphalt performance enhancement is 2% under the test conditions, as determined by comparing the test results of samples with various dosages.

Polymer-supported strong Lewis acid phosphonium cation catalysis applied to sydnone synthesis.

Organochlorophosphonium P(V) species are strong Lewis acids deriving from a low-lying σ* orbital at P opposite to Cl. Herein, applying this strong acidity to heterogenous reactivity, we introduce polymer-supported phosphorus(V)-mediated Lewis acid catalysis. Key to this innovation is the use of a recyclable solid support Merrifield resin P(V) Lewis acid catalyst with demonstrated utility for the one-pot synthesis of sydnones. This concept of pnictogen P(V) Lewis acid catalysis is simple to apply, selective, and benefits from mild conditions with short reaction times. Further, experimental and computational findings reveal the crucial mechanistic role of phosphonium cation P(V) species in these reactions.

Polyphenol content in tobacco (N. tabacum L.) and antioxidant activity

The aim of the present work is to determine the content of polyphenols in tobacco varieties and to investigate the antioxidant activity in tobacco extracts. Bulgarian tobacco varieties from the Basmi and Kabakulak variety groups produced conventionally and biologically, were used. Two types of extracts were investigated - crude extracts obtained by four solvents - 100% CH3OH, 60% CH3OH, H2O, and 96% C2H5OH, and purified extracts obtained by further purification of crude 60% methanolic extract using two techniques - solid phase extraction (SPE) and resin purification, Tobaccos from the variety group Basmi, conventionally grown, have a higher polyphenol content compared to the tobaccos from variety group Kabakulak. No significant difference was observed in the polyphenol contents of in conventionally and organically grown tobaccos of the same variety. The content of phenolic compounds in crude extracts by various solvents decreased in the following order: 60% CH3OH>H2O>100% CH3OH>96% C2H5OH. The crude and purified tobacco extracts showed high antioxidant activity determined by ABTS, FRAP and DPPH assays. The total phenolic content and antioxidant activity of 60% crude methanolic extracts were close to the SPE purified and resinpurified tobacco extracts

Keyland polymer opened a new R&D lab for UV-cured solid resins in Barcelona

Keyland polymer opened a new R&D lab for UV-cured solid resins in Barcelona

The Effect of Pt-type Catalysts on Self-adhesive Properties of Silicone Pressure-sensitive Adhesives

AbstractUseful silicone pressure-sensitive adhesives (PSAs) have been prepared from a high solid silicone resin. Platinum catalysts and crosslinking compounds were used to obtain new self-adhesive tapes. The influence of catalysts and crosslinking compounds on the basic properties of self-adhesive tapes was tested, taking into account the compatibility of silicone composition. The obtained systems showed good self-adhesive properties, and high thermal resistance over 225 °C. The low viscosity of the compositions obtained relatively increases the application potential of self-adhesive tapes based on it. Moreover, the prepared compositions show the potential for further modifications, especially physical ones e.g. silicon powder. The obtained new tapes showed good self-adhesive properties and kept high thermal resistance over 225 °C. It is well known that silicone pressure-sensitive adhesives are a group of silicone adhesives for special applications. Due to their unique resistance to environmental conditions, temperature and chemical resistance, they are difficult to modify.

Solid superacid catalysts promote high-performance carbon dots with narrow-band fluorescence emission for luminescence solar concentrators

Facile and efficient method for constructing carbon dots (CDs) with narrow full width at half maximum (FWHM) is a major challenge in the field, and researches on regulating the FWHM of CDs are also rare and scarce. In this work, we delved into the synthesis of CDs with narrow fluorescence emission FWHM (NFEF-CDs) in the m-phenylenediamine (m-PD)/ethanol system, utilizing solid superacid resin as catalyst with solvothermal method. The resulting NFEF-CDs exhibit a photoluminescent (PL) emission peak at 521 nm with a narrow FWHM of 41 nm, an absolute PL quantum yield (QY) of 80%, and display excitation-independent PL behavior. Through comprehensive characterization, we identified the protonation of edge amino on NFEF-CDs as the key factor in achieving the narrow FWHM. Subsequently, we validated the broad applicability of solid superacid resins as catalysts for synthesizing CDs with narrow FWHM in the m-PD/ethanol system. Finally, we utilized a self-leveling method to prepare NFEF-CDs film on the surface of poly(methyl methacrylate) (PMMA) substrate and investigated the solid-state fluorescence properties of NFEF-CDs as well as their performance as luminescence solar concentrator (LSC) for photovoltaic conversion. The results revealed that the as-prepared LSC exhibit an internal quantum efficiency (ηint) of 42.39% and an optical efficiency (ηopt) of 0.68%. These findings demonstrate the promising prospects of NFEF-CDs in the field of LSCs and provide a theoretical basis for their application in photovoltaic conversion.

Activation of inert triethylene tetramine-cured epoxy by sub-critical water decomposition

Cured epoxy is stable and difficult to be recycled. To make the inert cured epoxy and its derivatives or composites reactive is still a challenge. In this study, sub-critical water was used to decompose the solid diglycidyl ether-based epoxy resin (bisphenol A and bisphenol F) cured with triethylene tetramine (TETA) to reactive species. First of all, the thermally most unstable bonds in the epoxy resin underwent homogeneous cleavage reaction. Next, the generated free radicals were saturated by extracting hydrogen from the sub-critical water. The decomposition rate was improved with increasing the temperature and reaction time. During the reaction, breakage occurs preferentially in the epoxy resin main chain because of the existence of ether groups. The compounds evolved and the decomposition was analyzed. The experimental outcomes revealed that the decomposition mechanism of diglycidylether of bisphenol A (DGEBA)/TETA and diglycidylether of bisphenol F (DGEBF)/TETA resin regimes in sub-critical water may include side group elimination, random fracture and unzipping. Moreover, a segmented second-order kinetic analysis of the decomposition process was performed. The decomposition processes of two resins in sub-critical water were divided into two stages. Both stages were second-order reaction, the activation energy of DGEBA/TETA was 175 kJ/mol (Ea1(15-45min)), and 612 kJ/mol (Ea2(52.5-75min)). The activation energy of DGEBF/TETA was 258 kJ/mol (Ea1(15-45min)), and 686 kJ/mol (Ea2(52.5-75min)), respectively. This study provides a way for recycling inert epoxy wastes from different industrial fields and generating reactive and functional polymers.

Peptide Macrocyclization Guided by Reversible Covalent Templating.

The creation of complementary products via templating is a hallmark feature of nucleic acid replication. Outside of nucleic acid-like molecules, the templated synthesis of a hetero-complementary copy is still rare. Herein we describe one cycle of templated synthesis that creates homomeric macrocyclic peptides guided by linear instructing strands. This strategy utilizes hydrazone formation to pre-organize peptide oligomeric monomers along the template on a solid support resin, and microwave-assisted peptide synthesis to couple monomers and cyclize the strands. With a flexible templating strand, we can alter the size of the complementary macrocycle products by increasing the length and number of the binding peptide oligomers, showing the potential to precisely tune the size of macrocyclic products. For the smaller macrocyclic peptides, the products can be released via hydrolysis and characterized by ESI-MS.

Comparison on the performance of solid coumarone-indene resin and liquid coumarone-indene resin modified asphalt

Coumarone-indene resin (CIR) has great potential for use as an asphalt modifier because of the cost-effective, high viscosity, and excellent mechanical properties. CIR is classified into two types based on polymerization degree: solid coumarone-indene resin (S-CIR) and liquid coumarone-indene resin (L-CIR). In this study, solid coumarone-indene resin modified asphalt (S-CMA) and liquid coumarone-indene resin modified asphalt (L-CMA) were prepared, and the comparison of the high-temperature performance, compatibility, aging performance, low-temperature performance, microstructure and modification mechanism of S-CMA and L-CMA was researched following the SuperPave standard. The results reveal that S-CIR is a solid resin with a high molecular weight that improves the high-temperature performance, permanent deformation resistance, and viscosity of asphalt, but impact on low-temperature performance negatively. In contrast, L-CIR is a liquid resin with low molecular weight that enhances the low-temperature properties and plasticity of asphalt, but decreases high-temperature properties. Additionally, solid resins with large molecular weight are prone to agglomeration in asphalt, while liquid resins with small molecular weight have better dispersibility, especially in high-content situations. Meanwhile, CIR exhibits good compatibility with asphalt. Based on the FTIR test results, chemical compositions and structures of S-CIR and L-CIR are similar, and physical miscibility was demonstrated between CIR and asphalt. In summary, modifier with different molecular polymerization degrees have a greater impact on modified asphalt, S-CMA has better high-temperature performance and viscosity than L-CMA, L-CMA has better low-temperature performance and plasticity than S-CMA, and S-CMA and L-CMA can be used for pavement construction in hot and cold areas respectively.

Hydrogen-Deuterium Exchange Epitope Mapping of Glycosylated Epitopes Enabled by Online Immobilized Glycosidase.

Hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) is widely used for monoclonal antibody (mAb) epitope mapping, which aids in the development of therapeutic mAbs and vaccines, as well as enables the understanding of viral immune evasion. Numerous mAbs are known to recognize N-glycosylated epitopes and to bind in close proximity to an N-glycan site; however, glycosylated protein sites are typically obscured from HDX detection as a result of the inherent heterogeneity of glycans. To overcome this limitation, we covalently immobilized the glycosidase PNGase Dj on a solid resin and incorporated it into an online HDX-MS workflow for post-HDX deglycosylation. The resin-immobilized PNGase Dj exhibited robust tolerance to various buffer conditions and was employed in a column format that can be readily adapted into a typical HDX-MS platform. Using this system, we were able to obtain full sequence coverage of the SARS-CoV-2 receptor-binding domain (RBD) and map the glycosylated epitope of the glycan-binding mAb S309 to the RBD.

Wetting model of rough solid surfaces and the effect of aggregate properties on epoxy resin binder-aggregate interface wetting

In order to study the effect of aggregate characteristics on the wetting of epoxy resin binder-aggregate interface, based on the Wenzel model and Cassie model, this paper established a new wetting model of the irregular rough surface. The model regularizes the rough solid surface and can calculate the wetting depth and apparent contact angle between different irregular rough solids and liquids. The texture parameters of aggregates, the surface tension of test liquids and the contact angles of different liquids-aggregates were tested by laser confocal tester and optical contact angle measuring instrument. It was found that the surface texture parameters of different aggregates were quite different. The relative error between the apparent contact angle calculated by the prediction model and the contact angle measured by the test was less than 15 %, indicating that the prediction model had excellent prediction effect. Through the analysis of the wetting model, it is found that the surface tension of the test liquid, the lithology of the solid aggregate, the surface roughness and the texture structure are the important control parameters affecting the wetting. The surface morphology of rough solid can be designed by changing the resolution k and depth H of micropores, so as to control the wettability of solid aggregate surface and epoxy resin aggregate.

Dansyl linked solid phase resins as an educational tool to teach the concepts of high throughput screening and prodrugs.

High throughput screening (HTS) and combinatorial chemistry, have been part of the process of drug design for nearly two decades. However, methods to teach their practical aspects to undergraduate students are scarce in the literature.1-3 The authors describe the synthesis and reactivity, under hydrolytic and transesterification conditions, of newly prepared fluorescent solid phase resins, envisaged to teach the concept of HTS, and prodrugs, to undergraduate students. Although the enzymatic methods did not perform well, the chemical hydrolysis, and the transesterification reaction, of these new solid phase resins, worked in very good yields, and produced very useful results. In relation to the experiment, the student’s learning experience, and feedback, were very positive.

Cytotoxicity of dental self-curing resin for a temporary crown: an in vitro study.

Residual monomer tests using high-performance liquid chromatography and cytotoxicity tests were performed to analyze the effect on the oral mucosa of a self-curing resin for provisional crown production. A cytotoxicity test was performed to confirm whether leaked residual monomers directly affected oral mucosal cells. The cytotoxicity of the liquid and solid resin polymers was measured using a water-soluble tetrazolium (WST) test and microplate reader. In the WST assay using a microplate reader, 73.4% of the cells survived at a concentration of 0.2% liquid resin polymer. The cytotoxicity of the liquid resin polymer was low at ≤0.2%. For the solid resins, when 100% of the eluate was used from each specimen, the average cell viability was 91.3% for the solid resin polymer and 100% for the hand-mixed self-curing resin, which is higher than the cell viability standard of 70%. The cytotoxicity of the solid resin polymer was low. Because the polymerization process of the self-curing resin may have harmful effects on the oral mucosa during the second and third stages, the solid resin should be manufactured indirectly using a dental model.

Study Direction to Oxidize a Local Pine Rosin with Potassium Permanganate

Pine rosin acid or Gondorukem is a solid resin obtained from pine sap. It is yielded as residue from a high temperature distillation process. In industry, rosin acid is widely used and modified as raw material in paint, ink, adhesive, resin, thermoplastic, and thermosetting polymer. Modification process generally is undergone to generate rosin acid with specific properties and for certain purposes. This paper report, potassium permanganate oxidation reaction of pine rosin acid under acidic process at low temperature. Product identified as 13,14-seco-13-oxoabiet-7-ene-dioic acid (0.52%), 7,8-dihydroxy-abietic acid (6.62%), and 7-oxo-dehydroabietic acid (1.49%). The crude product was isolated as a pale to white solid. Under high temperature a yellowish product was resulted. In overall, the yield isolated in between 46.4% and 86.0%.

Hydrophile-lipophile balance solid phase extraction of surface water organics: Fluorescent elution preference and overlooked fractions

Fluorescent dissolved organic matter (FDOM) in surface water has broad implications on water quality research and operations. Solid phase extraction (SPE) is the most widely used technique to extract FDOM. However, fluorescent elution preferences by common solvents and content of quantifiable chromophores in waste fraction remain largely unknown, both quantitatively and qualitatively. In this work, the preferential selection of various types of FDOM captured by and lost from SPE as characterized by the fluorescence excitation-emission matrix (EEM) were investigated. Three elution solvents (methanol, acetone, and dichloromethane) were adopted to elute the DOM that was enriched on a typical SPE sorbent. Results revealed that high polarity (methanol) and medium polarity (acetone) solvents eluted the highest variety and quantity of humic acid-like substances (Region V), while the low polarity (dichloromethane) elution solvent was more suitable for eluting tyrosine (Region I) and tryptophan (Region II). Compared to eluting only with methanol, sequential elution and recombination using the three aforementioned solvents demonstrated a significant increase in not only DOC recovery (by 7%), but fluorescence integral values and fluorescence characteristics covering collectively much larger fluorescence regions that more closely resembled raw water. For the first time, the fluorescence EEM of waste after loading the sample revealed a previously overlooked FDOM loss of 20%, caused by ineffective adsorption onto the solid phase resin. Substantial carbonaceous and nitrogenous FDOM were present in this fraction (the fluorescence intensity of aromatic protein in waste exceeds 20% of that in raw water), indicating possible underestimations of FDOM-related research in areas such as disinfection byproduct and toxicity work. The results of this study provide both a qualitative and quantitative characterization of the elution and lost products of SPE in capturing FDOM.