Trimethylolpropane Trimethacrylate Research Articles

Thermal Characterization of Crosslinked Polymeric Microspheres Bearing Thiol Groups Studied by TG/FTIR/DSC under Non-Oxidative Conditions.

This paper presents the thermal behavior of polymer microspheres based on glycidyl methacrylate (GMA) and crosslinking agents benzene-1,4-diylbis(2-methylprop-2-enoate) (1,4DMB) and trimethylolpropane trimethacrylate (TRIM) before and after functionalization with thioglycolic acid (TGA). The thermal stability of the polymers was determined using thermogravimetric analysis and differential scanning calorimetry under non-oxidizing conditions. The evolved gases were detected by FTIR and NMR spectroscopy, and the chemical structure of solid residues after preheating was assessed by FTIR/ATR spectroscopy. The post-functionalized microspheres showed higher thermal stability (within 270-290 °C) than the initial copolymers (within 240-250 °C). In this paper, examples of decomposition patterns of polymer microspheres before and after functionalization are presented. The decomposition of the initial microspheres starts with the emission of GMA monomers, acrolein, carbon dioxide, and the formation of unsaturated bonds in the solid residue. In the case of functionalized microspheres, degradation involves the transesterification of ester groups with the -SH groups, resulting in the emission of carbonyl sulfide, acrolein and carbon dioxide. Furthermore, lactone groups are created in the solid residue. The degradation of the functionalized copolymers is a complex process due to their crosslinked structure, rendering the identification of all the degradation products unattainable.

Imprinting-based smart syringe: A fast, efficient, and selective approach for extraction of methyl gallate from Caesalpinia pulcherrima extract

A simple, facile, quick, highly selective, and efficient extraction protocol for a medicinal compound methyl gallate (MG) is developed for the first time using molecularly imprinted-based solid phase extraction (MISPE). Density functional theory (DFT) was employed to calculate the binding energies of the complex of MG with the functional monomer in the gas and in the implicit solvent to evaluate the best combination of the functional monomer, crosslinker, and porogen for MG. Decisively, the synthesis of a molecularly imprinted polymer (MIP) and its respective non-imprinted polymer (NIP) was conducted using methacrylamide (MAAm) as a functional monomer, trimethylolpropane trimethacrylate (TRIM) as a crosslinker, and methanol as a porogen. The polymers were characterized by SEM, FT-IR, BET, and TGA, while the adsorption properties of MG-MIP/NIP were evaluated by batch rebinding experiments. Theoretical modeling was done by Langmuir, Freundlich, Scatchard analysis, LF-isotherm, and kinetic models. The MG-MIP appeared to have a higher binding capacity towards MG compared to the corresponding NIP: 57.6 mg/g compared to only 17.6 mg/g rendering an imprinting factor 3.3. Moreover, in competitive recognition studies, the synthesized MG-MIP showed good selectivity towards MG compared to its structural analogs, confirming the presence of MG-specific imprinting sites. In competitive recognition tests and real-sample analysis, HPLC was used to determine the concentration of MG and the analogous compounds. Furthermore, the volume and elution times of the washing solvent (DI water) and elution solvent (acetonitrile) were optimized. Finally, MG-MISPE frits were successfully designed for selective enrichment of MG from Caesalpinia pulcherrima methanolic extract using a syringe, PTFE membrane, and MG-MIPs. Hence, MG-MISPE is a promising alternative of traditional extraction methods for selective extraction and enrichment of MG from complex plant matrices. The approach has potential to be applied to any compound of interest.

A pragmatic approach to analyze the ability of ethylene‐octene copolymer in the long chain branching of polypropylene in molten and solid state

AbstractThe investigation of chain branching in polypropylene (PP) holds significant importance for comprehending the impact of structural modifications on the properties of PP. The utilization of ethylene‐octene copolymer (EOC) presents a valuable opportunity to examine the influence of branching density on the ability of electron beam irradiation or a chemical agent in a PP blend. The introducing long chain branches (LCB) into PP can enhance its mechanical properties, particularly impact strength. This characteristic is of particular significance in applications where the material is subjected to mechanical stress, such as automotive components or packaging materials. Blends of PP/EOC were produced using 20 and 30 wt% of EOC and 0.5 phr trimethylolpropane trimethacrylate (TMPTMA) monomer. To evaluate the efficiency of branching in both solid and molten states, irradiated samples and samples mixed with dicumyl peroxide (DCP) were selected. The rheological properties of the molten blends in shear and extensional modes were assessed, and their morphology was examined using scanning electron microscopy. The existence of LCB in all samples was confirmed through dynamic viscoelastic measurements. It was concluded that although the irradiation promoted chain scission within the backbone, which resulted in long chain branching, DCP created LCB on the backbone chains of PP through chemical reaction in the melt state. Additionally, the strain hardening constant (n) was calculated, and its value for the irradiated sample PP/EOC 80/20 was 0.19, whereas its value for this blend when employing DCP was 0.14. While the complex viscosity of irradiated blend (8764 Pa.s) was greater than that of melt state branched blend (8377 Pa.s) at 0.1 rad/s, in the higher frequencies it became smaller due to the more effective creation of long chain branches through peroxide grafting in the molten state. The results of the study verified the presence of LCB in the materials by observing longer relaxation time and strain hardening behavior.Highlights The chain branching of PP/EOC blends was investigated in both the melt state and solid state through the presence of TMPTMA monomer. The effectiveness of TMPTMA monomer in grafting was mostly notable in the molten state. The steady state viscosity of LCB‐(PP/EOC) was higher in the presence of dicumyl peroxide compared to irradiated PP/EOC. The samples containing 80 wt% of PP exhibited longer side branches compared to the sample with 70 wt% of PP according to shear and extensional rheometry. The induced side chain branches resulting from irradiation and the use of dicumyl peroxide help increase the miscibility of the polymers to a similar extent.

Rheological behaviors and foaming behaviors of crosslinked ethylene–vinyl acetate with polyfunctional monomers

AbstractTo produce ethylene–vinyl acetate (EVA) foams with a higher foaming ratio and stable cell size, the efficiency of the crosslinking reaction is required to conduct simultaneously with the blowing reaction. Hence, the multifunctional monomer trimethylolpropane trimethacrylate (TMP) as a crosslinking promoter and a crosslinking agent dicumyl peroxide are used together as a crosslinking system to EVA foaming, when chemical blowing agent azodicarbonamide (ADC) is used. The TMP concentration of approximately 1.0 phr (per hundred resin) is most effective for balancing the expansion ratio and fine cell size. In the SEM diagram and expansion ratio results, it can be found that when the concentration of TMP ranges from 0 to 1.0 phr, the cell mean size is reduced from 360.3 to 140.5 μm and the expansion ratio is reduced from 13.6 to 9.1 at 170°C. The results of time‐sweep experiment of thermogravimetric analysis (TGA) show that the foaming time of ADC in the melt increases with the addition of TMP. Capillary rheometer and rotational rheometer tests show that the viscosity and the crosslinking efficiency of the melt are improved with the TMP addition. The curing time has been reduced from 2.93 to 2.22 min for 170°C.

Selective capture of uranium and zirconium from strong HNO3 solution by ethenylphosphonic acid copolymerized polymer

The nuclear fuel rod contains mainly uranium (U) as the fuel and zirconium (Zr) as the cladding material. Improper disposition of the dissolved solution of the exhausted fuel rod releases radioactive acidic aqueous solution, which is a waste of U and Zr resources and also poses a great threat to the environment and living beings. The present work aims to selectively capture U and Zr from a 4 mol/L HNO3 aqueous solution in the presence of competing ions including La, Zn, Cd, Gd, Ce, Sr, Mn, Cu and Ba. Trimethylolpropane trimethacrylate (TMPTMA) copolymerized with ethenylphosphonic acid (EPA). TMPTMA improved the mesoporous character and adsorption ability of the adsorbent towards U and Zr. The synthesized polymer adsorbent was characterized by SEM, EDS, FT-IR, TGA, XRD, BET, XPS, and NMR to study the adsorption. The results indicated that the EPA-POP-2 adsorbent showed considerable adsorption capacity towards U(VI) (374.1 mg g−1) and Zr(IV) (217.4 mg g−1) in a strong HNO3 medium. Langmuir isotherm model fitted well to the experimental data, indicating that the monolayer adsorption process was dominating. The fitted pseudo-second-order (PSO) model represents that the adsorption mechanism is chemisorption. XPS, FT-IR, and DFT calculation results revealed that this adsorption capacity towards U and Zr was because of the P = O ligands present in the adsorbent. Van’t Hoff graph for U and Zr were also drawn to calculate the enthalpy, entropy, and Gibb’s free energy of the reaction. The reusability test showed that the adsorption capacity of synthesized adsorbent was high enough towards the U and Zr even after five consecutive cycles of adsorption and desorption.

Synthesis of molecularly printed methyl methacrylate-based polymers for the detection of di(2-ethylhexyl) phthalate and dibutyl phthalate

Molecularly imprinted polymers (MIP) were obtained by precipitation polymerization for the detection of DEHP and DBP from polymer packaging in drinking water. MIP was obtained by cross-linking DEHP and DBP with methyl methacrylate (MMA) and trimethylolpropane trimethacrylate (TRIM). FTIR, SEM-EDS, UV-Vis and SAA were used to determine properties of polymers (MIP_DEHP, MIP_DBP). The obtained materials were characterized by a mesoporous structure with small, uniform, and porous grains. The surface area and total pore volume of MIP_DEHP were more than twice smaller than MIP_DBP, with a slightly larger pore diameter. Lower C content may indicate the formation of MIP_DEHP and MIP_DBP. The FTIR method confirmed the presence of functional groups –CH, –CO, –C=C and –C=O. The adsorption capacity of MIP_DEHP and MIP_DBP was 0.68 mg/g and 1.06 mg/g, respectively, and was consistent with the Freundlich isothermal adsorption model.

Improved direct current electrical properties of XLPE modified by graftable antioxidant and crosslinking coagent at a wide temperature range

AbstractTo enhance the DC electrical performance of cross‐linked polyethylene (XLPE), the graftable antioxidant methacrylic acid 2‐hydroxy‐3‐(4‐anilinoanilino) propyl ester (GA), which contains carbonyl and amino groups, and the crosslinking coagent trimethylolpropane trimethacrylate (TMPTMA), which contains carbonyl groups, are individually or co‐grafted onto XLPE. The slightly higher deep trap density introduced by higher grafting concentration of TMPTMA results in more significant suppression effect of conductance current and enhanced breakdown strength at a lower temperature, while the suppression effect for the conductance current at 90°C becomes weakened due to limited trap energy. Meanwhile, the deeper energy level introduced by GA suppresses the conductance current and improves the electrical strength of XLPE at 90°C more significantly. By co‐grafting, the conductance current of XLPE in a wide range temperature can be significantly reduced, especially for the temperature dependence of conductance current, which is beneficial to suppress the field strength reversal. The results of thermally stimulated current and molecular simulation show that the polar groups of two monomers introduce deep charge traps in XLPE. The co‐grafting system ensures the rationality of the crosslinking reaction kinetics and does not affect the cable manufacturing.

Multivariate design and application of novel molecularly imprinted polymers selective for triazole fungicides in juice and water samples

In the present study, novel molecularly imprinted polymers were prepared using penconazole as template and different combinations of functional monomers (acrylic acid (AA) and N-isopropylacrylamide (NIPAM)) and cross-linkers (ethylene glycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TRIM)), according to a Plackett-Burman design of experiments. Materials were fully characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and nitrogen adsorption analysis. Rebinding behaviors in solution were studied both at the equilibrium (Langmuir, Freundlich and Temkin models), and at the non-equilibrium (pseudo-first, pseudo-second order kinetics). Materials were further tested as sorbents for dispersive solid phase extraction (d-SPE) on apple juice for multicomponent recovery of triazole fungicides at trace level, testing several variations of extraction parameters (juice pH, amount of sorbent, adsorption time, desorption solvent, desorption time) leading to the selection of the best materials and simultaneously of the best extraction conditions. MIPs synthesized with NIPAM showed significatively higher affinity for triazole pesticides in apple juice than the ones synthesized with AA, while no differences emerged for the two cross-linkers employed (EGDMA, TRIM). Selectivity was also assessed, testing MIPs as d-SPE sorbents in undiluted apple juice spiked with triazole pesticides concurrently with other interfering compounds. The newly developed NIPAM-based penconazole-imprinted MIPs showed an excellent recognition mechanism towards compounds containing the triazole ring, and significatively lower recoveries for other compounds. The developed analytical procedure based on molecularly imprinted polymer dispersive solid phase extraction and liquid chromatography coupled with mass spectrometry (MIP-d-SPE-LC-MS) was validated for selective enrichment and determination of triazole compounds in apple juice samples and river water samples with good recoveries (94.67%–109.03% for river water, 89.79%–110.23%, for apple juice), high repeatability (RSD% < 3.97 for river water, RSD% < 4.85 for apple juice), and reproducibility (RSD% < 5.95 for river water and RSD% < 7.14 for apple juice).

A Label-Free Electrochemical Biosensor for Homocysteine Detection Using Molecularly Imprinted Polymer and Nanocomposite-Modified Electrodes.

An essential biomarker for the early detection of cardiovascular diseases is serum homocysteine (Hcy). In this study, a molecularly imprinted polymer (MIP) and nanocomposite were used to create a label-free electrochemical biosensor for reliable Hcy detection. A novel Hcy-specific MIP (Hcy-MIP) was synthesized using methacrylic acid (MAA) in the presence of trimethylolpropane trimethacrylate (TRIM). The Hcy-MIP biosensor was fabricated by overlaying the mixture of Hcy-MIP and the carbon nanotube/chitosan/ionic liquid compound (CNT/CS/IL) nanocomposite on the surface of a screen-printed carbon electrode (SPCE). It showed high sensitivity, with a linear response of 5.0 to 150 µM (R2 of 0.9753) and with a limit of detection (LOD) at 1.2 µM. It demonstrated low cross-reactivity with ascorbic acid, cysteine, and methionine. Recoveries of 91.10-95.83% were achieved when the Hcy-MIP biosensor was used for Hcy at 50-150 µM concentrations. The repeatability and reproducibility of the biosensor at the Hcy concentrations of 5.0 and 150 µM were very good, with coefficients of variation at 2.27-3.50% and 3.42-4.22%, respectively. This novel biosensor offers a new and effective method for Hcy assay compared with the chemiluminescent microparticle immunoassay at the correlation coefficient (R2) of 0.9946.

Core-shell magnetic molecularly imprinted polymers: nanoparticles targeting selective androgen receptor modulators (sarms) and steroidal models

Super paramagnetic iron oxide nanoparticles (SPIONs) (∼12 nm) were synthesized as the magnetic core for an imprinted polymer (MIP) shell using 4-vinylpyridine as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the cross-linker, bringing the average size up to ∼45 nm. Five targets were imprinted—the Selective Androgen Receptor Modulators (SARMs) andarine, ligandrol and RAD-140; and the steroids estradiol and gestrinone. All MMIPs produced good selectivity when loaded with a non-target molecule, with all calculated selectivity factors above the 1.2 recommended threshold and also demonstrated good affinity/capacity. The rebinding of the target molecules from a complex matrix was also explored by using spiked river water samples. The SARMs-based MMIPs were able to rebind 99.56, 87.63 and 72.78% of their target molecules (andarine, ligandrol and RAD-140, respectively), while the steroidal-based MMIPs were able to rebind 64.54 and 55.53% of their target molecules (estradiol and gestrinone, respectively) at a nominal loading of 20 ≈μg in 50 mg of NPs. This work highlights the potential of these bi-functional materials for trace material clean-up of complex samples and/or subsequent analysis and opens up possibilities for further simple, rapid-to-synthesise materials for targeted clean-up.

Using maturity method to predict compressive strength of acrylic polymer concrete containing TMPTMA or silane at sub-zero curing temperatures

Acrylic polymer concrete (APC) is a fast-setting and high-strength material with low freezing point, and can gain strength even at sub-zero temperatures, making it an excellent option for repairing pavements and roads during cold weather. Accurately estimating the compressive strength of APC is critical for determining safety time to open the pavement to traffic. Unfortunately, traditional maturity methods, such as those recommended by ASTM C1074 for Portland cement concrete, cannot be applied directly for strength estimation of APC. In order to estimate the compressive strength of APC containing 0–5 phr trimethylolpropane trimethacrylate (TMPTMA) or 0–2 phr silane cured at sub-zero temperatures, the Arrhenius equation-based maturity method has been modified and utilized for the first time in this study. An exponential function is adopted to characterize strength development of APC cured at different temperatures (-20-0 °C), with the assumption that the ultimate compressive strength of APC is independent of curing temperature. The corresponding activation energies (Ea) for APC are determined using Arrhenius equation. The findings indicate that the Ea value of APC without any additives is 39.65 kJ/mol. Moderate amount addition of TMPTMA (0–1 phr) enhances the temperature sensitivity, however, silane incorporation alone significantly reduces Ea value by 7–12 kJ/mol. The Ea values are also utilized to estimate the compressive strength of APC, based on the equivalent time at the reference temperature (0 °C). The modified maturity method effectively predicts the compressive strength of APC cured under sub-zero temperatures. The estimated values closely match experimental data with errors controlled in ±10%. This work will provide basis and instruction on estimating strength and determining the safe timing for traffic opening when APC is used as a patch repair for roads and pavements.

Photocrosslinking of ethylene‐vinyl acetate (EVA)–polyethylene‐octene (POE) copolymer containing halogen‐free flame retardants

AbstractPhotocrosslinking of polymers for industrial applications show undoubted advantages related to the mild conditions needed and the economical equipment. However, some issues include: the use of (i) mercury lamps as light sources, which poses concerns about safety and energy consumption, (ii) typical additives, such as halogen‐free flame‐retardant fillers (HFFR) are powdered materials, which can scatter UV photons and avoid a deep penetration of the light. In this study, we explore the UV‐curing of an innovative EVA‐POE blend containing hydrotalcite and aluminum hydroxide as HFFR in the presence of a 370‐nm UV LED, namely Ekopren® XI1321, a plastic used as coverage for electric cables. Two commercially available photoinitiators (benzophenone and ethyl Michler's ketone) were analyzed as well as two crosslinking coagents widely used in industry, that is, triallyl cyanurate and trimethylolpropane trimethacrylate. A comparison with pure EVA and LDPE was performed to show a higher cross‐linked content of the proposed blend, even in the presence of light scattering mineral fillers at high concentration.

Novel Ion-imprinted Polymer as a Tool for Selective Determination of SbIII in Natural Waters

A novel SbIII-imprinted polymer was synthesized via radical copolymerization of methacrylic acid and trimethylolpropane trimethacrylate in the presence of 2-mercapto-N-(2-naphthyl)acetamide as a chelating ligand forming the functionality of specific binding sites. The extent of ligand incorporation in the active centres was evaluated by elemental analysis and found to be 73.6%. The IIP was utilized as a sorbent material for selective solid-phase extraction of SbIII in drinking waters after optimization of sorption and desorption processes in a batch mode. Excellent separation of SbIII and SbV was accomplished at pH 8 followed by elution of SbIII with 0.5 M thiocarbamide. Analytical procedure for non-chromatographic speciation and determination of SbIII was developed demonstrating very good precision (RSD 7–11%) and recoveries between 97–105%. This procedure enabled up to 25-fold reconcentration and completely met the requirements of EU legislation for the quality of water intended for human consumption.

Extraction-assisted voltammetric determination of homocysteine using magnetic nanoparticles modified with molecularly imprinted polymer

Amagnetic graphite-epoxy composite (m-GEC) electrochemical sensor is presentedbased on magnetic imprinted polymer (mag-MIP) to determine homocysteine (Hcy). Mag-MIP was synthesized via precipitation polymerization, using functionalized magnetic nanoparticles (Fe3O4) together with the template molecule (Hcy), the functional monomer 2-hydroxyethyl methacrylate (HEMA), and the structural monomer trimethylolpropane trimethacrylate (TRIM). For mag-NIP (magnetic non-imprinted polymer), the procedure was the same in the absence of Hcy. Morphological and structural properties of the resultant mag-MIP and mag-NIP were examined usingTEM, FT-IR, and Vibrating Sample Magnetometer. Under optimized conditions, the m-GEC/mag-MIP sensor showed a linear range of 0.1-2µmol L-1, with alimit of detection (LOD) of 0.030µmol L-1. In addition, the proposed sensor responded selectively to Hcy compared to several interferents present in biological samples. The recovery values determined by differential pulse voltammetry (DPV) were close to 100% for natural and synthetic samples, indicating good method accuracy. The developed electrochemical sensor proves to be a suitable device for determining Hcy, with advantages related to magnetic separation and electrochemical analysis.

Molecular Imprinting of Benzylpiperazine: A Comparison of the Self-Assembly and Semi-Covalent Approaches

Molecularly imprinted polymers (MIPs) for benzylpiperazine (BZP, 1), an illicit designer drug, were developed by using both self-assembly and semi-covalent approaches. From an array of potential functional monomers (FMs) and using a combination of pre-synthetic interaction studies (by molecular modelling and NMR analysis) and binding assays, the highest performing self-assembly 1-MIPs were confirmed to result from methacrylic acid (7) as FM, ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TRIM) as crosslinkers and chloroform as the porogen and rebinding solvent at template (T): FM ratios of 1:1 and 1:2, giving imprinting factors (IF) 3 to 7. The semi-covalent 1-MIPs were designed using benzylpiperazine (4-vinylphenyl) carbamate (16) as the template-monomer adduct in combination with either EDGMA or TRIM. Our comparative analysis showed the semi-covalent polymers to have a stronger affinity for 1 (significantly lower Kd values and higher IFs) and faster uptake than the self-assembly systems. Both approaches have comparable cross-reactivity: marginal to low against cocaine (17) and morphine (18) and high against ephedrine (19) and phenylpiperazine (20). They also have comparable selectivity: highly selective towards 1 against 17, moderate against 18 and non-selective against 19. EGDMA-based self-assembly MIPs displayed a greater imprinting effect (higher IFs and NIP-to-MIP Kd ratios) than TRIM-based MIPs, while the TRIM-based semi-covalent MIP outperformed its EGDMA-based equivalent. By virtue of its modest selectivity against the test illicit drugs, 1-MIPs could potentially be used as a dummy MIP for the broad-based capture and enrichment of illicit drug blends for subsequent laboratory analysis.

Synthesis and thermal characterization of porous polymeric microspheres functionalized with thiol groups

The paper presents a method of the preparation and functionalization of polymer microspheres consisting of glycidyl methacrylate (GMA) and crosslinking agents: 1,4-dimethacryloyloxybenzene (1,4DMB) and trimethylolpropane trimethacrylate (TRIM). Poly(GMA-co-1,4DMB) and poly(GMA-co-TRIM) microspheres were obtained by seed swelling polymerization. To introduce thiol groups into the microspheres structure, the reaction with thiocarboxylic acids was performed. The chemical structure of parent and modified microspheres was confirmed by FTIR and Raman spectroscopy. Elemental composition of microspheres after functionalization was determined by elemental analysis. The analysis showed the percentage of sulfur in the range of 2.78–4.51%, which corresponds to a concentration of thiol group in the range of 0.87–1.41 mmol g−1. Additionally, the porous structure of the copolymers was investigated using the low-temperature nitrogen adsorption–desorption method. The starting microspheres are characterized by a specific surface in the range of 150–160 m2 g−1, whereas functionalized copolymers indicate slightly lower surface area, of about 130 m2 g−1. The thermal stability of the materials was determined by the method of differential scanning calorimetry and thermogravimetric analysis. The course of the thermal degradation under oxidative conditions of modified microspheres is different from the starting copolymers. The functionalized microspheres showed much higher thermal stability (approximately 270 °C) compared to the starting microspheres (230–250 °C).

Raclopride-Molecularly Imprinted Polymers: A Promising Technology for Selective [11C]Raclopride Purification.

In this work, we developed a novel approach to purify [11C]Raclopride ([11C]RAC), an important positron emission tomography radiotracer, based on tailored shape-recognition polymers, with the aim to substitute single-pass HPLC purification with an in-flow trap & release process. Molecular imprinting technology (MIT) applied to solid phase extraction (MISPE) was investigated to develop a setting able to selectively extract [11C]RAC in a mixture containing a high amount of its precursor, (S)-O-Des-Methyl-Raclopride (DM-RAC). Two imprinted polymers selective for unlabeled RAC and DM-RAC were synthesized through a radical polymerization at 65 °C using methacrylic acid and trimethylolpropane trimethacrylate in the presence of template molecule (RAC or DM-RAC). The prepared polymer was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and tested in MISPE experiments. The polymers were used in testing conditions, revealing a high retention capacity of RAC-MISPE to retain RAC either in the presence of similar concentrations of RAC and DM-RAC precursor (96.9%, RSD 6.6%) and in the presence of a large excess of precursor (90%, RSD 4.6%) in the loading solution. Starting from these promising results, preliminary studies for selective purification of [11C]Raclopride using this RAC-MISPE were performed and, while generally confirming the selectivity capacity of the polymer, revealed challenging applicability to the current synthetic process, mainly due to high backpressures and long elution times.

Binary systems for the trimethylolpropane triacrylate and trimethylolpropane trimethacrylate in supercritical carbon Dioxide: Experiment and modeling

The phase equilibrium data for two binary mixes of trimethylolpropane triacrylate (TMPTA) and trimethylolpropane trimethacrylate (TMPTMA) in supercritical CO2 are given. The mixture's experimental isotherms were determined at five different temperature windows, ranging from 313.2 K to 393.2 K, and maximum pressure of 32.23 MPa. The continuous critical mixture plot displayed by both binary mixtures indicates type-I behavior. At any temperature and composition, none of the systems under study exhibited three phases. The critical point for TMPTA + supercritical CO2 mixtures shifts to a higher pressure as temperature increases; however, no critical point was found for TMPTMA + supercritical CO2 mixture.Experimental phase behavior data is correlated with the Peng-Robinson two parameter cubic equation of state. Using two mixing parameters, all the isotherms in (P, x) space are predicted with satisfactory accuracy.

Cross-Linked Ionic Liquid Polymer for the Effective Removal of Ionic Dyes from Aqueous Systems: Investigation of Kinetics and Adsorption Isotherms.

In the current study, we have synthesized an imidazolium based cross-linked polymer, namely, 1-vinyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide (poly[veim][Tf2N]-TRIM) using trimethylolpropane trimethacrylate as cross linker, and demonstrated its efficiency for the removal of two extensively used ionic dyes-methylene blue and orange-II-from aqueous systems. The detailed characterization of the synthesized poly[veim][Tf2N]-TRIM was performed with the help of 1H NMR, TGA, FT-IR and FE-SEM analysis. The concentration of dyes in aqueous samples before and after the adsorption process was measured using an UV-vis spectrophotometer. The process parameters were optimised, and highest adsorption was obtained at a solution pH of 7.0, adsorbent dosage of 0.75 g/L, contact time of 7 h and dye concentrations of 100 mg/L and 5.0 mg/L for methylene blue and orange-II, respectively. The adsorption kinetics for orange-II and methylene blue were well described by pseudo-first-order and pseudo-second-order models, respectively. Meanwhile, the process of adsorption was best depicted by Langmuir isotherms for both the dyes. The highest monolayer adsorption capacities for methylene blue and orange-II were found to be 1212 mg/g and 126 mg/g, respectively. Overall, the synthesized cross-linked poly[veim][Tf2N]-TRIM effectively removed the selected ionic dyes from aqueous samples and provided &gt;90% of adsorption efficiency after four cycles of adsorption. A possible adsorption mechanism between the synthesised polymeric adsorbent and proposed dyes is presented. It is further suggested that the proposed ionic liquid polymer adsorbent could effectively remove other ionic dyes and pollutants from contaminated aqueous systems.

Enhancement of the properties of carbon-black-filled natural rubber compounds containing soybean oil cured with peroxide through the addition of coagents

Due to the hazard of the commercial rubber processing oil such as distillate aromatic extract (DAE), many rubber researchers play attention to find the green alternatives. Vegetable oils seem to gain a lot of attraction for this. It is not just only due to their environmentally friendly nature but also their abundance and affordable cost. The use of soybean oil (SBO) for the carbon black-filled rubber compounds was focused here and comparatively discussed with the use of DAE. Furthermore, this work also proposed the way to improve the mechanical properties and environmental endurance of the rubber compounds containing SBO by adding coagents. There were two types of coagent including trimethylolpropane trimethacrylate (TMPTMA) and triallyl isocyanurate (TAIC) used here. It was found that the cure time, cure rate index, and cure reaction rate constant of SBO-added rubber compounds with and without coagents were higher than those of DAE-added rubber compounds, whereas the activation energy of SBO-added rubber compounds was lower than the one with DAE. Without coagent, the mechanical properties of rubber compounds with DAE and SBO are equal. However, the addition of coagents improved the mechanical properties of rubber compounds containing SBO. The modulus at 100% strain, modulus at 200% strain, and tensile strength of TMPTMA-added rubber compounds increased by 41%, 48%, and 15%, respectively, whereas the rubber compounds with TAIC increased by 7%, 8%, and 20%, respectively, when compared to the one with SBO alone. Interesting, the SBO-added rubber compounds with and without coagents showed better thermal aging and ozone resistances than the DAE-added rubber compounds. All results showed that the presence of coagents especially TMPTMA gave the SBO-added rubber compound with the superior performance to the DAE-added rubber compound and the SBO-added rubber compound without coagent.