Commercial Resin Research Articles

Screening of six cation exchange resins for high binding capacity, monomer purity and step yield: A case study

Cation exchange (CEX) chromatography has been widely used as a polishing step in downstream processing of therapeutic monoclonal antibodies (mAbs). It has been well documented that the performance of a particular CEX resin heavily relies on buffer type, pH and conductivity. In this work, with a case study, we screened six commercial CEX resins under different pHs and conductivities. Initial screening was conducted on Tecan to find conditions under which high binding capacity was achieved. Next, performance of each resin was further evaluated using a small column under the identified optimum binding conditions. Variations in binding capacity and purity of eluate were observed among these resins. The adopted approach allows for identification of resins exhibiting good binding capacity, aggregate clearance and recovery.

3D-printed mouthpiece adapter for sampling exhaled breath in medical applications

The growing use of 3D printing in the biomedical sciences demonstrates its utility for a wide range of research and healthcare applications, including its potential implementation in the discipline of breath analysis to overcome current limitations and substantial costs of commercial breath sampling interfaces. This technical note reports on the design and construction of a 3D-printed mouthpiece adapter for sampling exhaled breath using the commercial respiration collector for in-vitro analysis (ReCIVA) device. The paper presents the design and digital workflow transition of the adapter and its fabrication from three commercial resins (Surgical Guide, Tough v5, and BioMed Clear) using a Formlabs Form 3B stereolithography (SLA) printer. The use of the mouthpiece adapter in conjunction with a pulmonary function filter is appraised in comparison to the conventional commercial silicon facemask sampling interface. Besides its lower cost – investment cost of the printing equipment notwithstanding – the 3D-printed adapter has several benefits, including ensuring breath sampling via the mouth, reducing the likelihood of direct contact of the patient with the breath sampling tubes, and being autoclaveable to enable the repeated use of a single adapter, thereby reducing waste and associated environmental burden compared to current one-way disposable facemasks. The novel adapter for breath sampling presented in this technical note represents an additional field of application for 3D printing that further demonstrates its widespread applicability in biomedicine.

Cyanate Ester Resin with High Heat‐Resistance and Degradable Diacetal Structure: Synthesis, Polymerization, and Properties

AbstractCyanate resins are high‐performance thermosetting resins with excellent mechanical, thermal, and dielectric properties. In this work, a novel cyanate ester monomer, 3,9‐bis‐(4‐cyanato‐phenyl)‐2,4,8,10‐tetraoxa‐spiro[5.5]undecane structure (DBCE), is prepared based on a diphenol (DB) with a degradable diacetal structure. The characterization of the chemical structures and polymerization behaviors of the samples are achieved by nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy, and differential scanning calorimetry. The obtained results confirm the successful syntheses of DB and DBCE, and the polymerization temperature of DBCE is between 160 °C to 250 °C, which is lower than that of a comparative commercial cyanate ester resin (BADCy). The thermal and dielectric properties of the curedresin (Poly‐DBCE) are explored by dynamic mechanical analysis, thermogravimetric analysis, and an Agilent impedance analyzer. The results reveal that Poly‐DBCE manifest promising heat resistance (Tg = 294 °C) and thermal stability (Td,5 = 347 °C and char yield at 800 °C = 37.6%). The dielectric constant and dielectric loss of the Poly‐DBCE at 10 MHz are 3.11 and 0.0095, respectively. Additionally, the Poly‐DBCE is completely degraded under mildly acidic conditions, and efficient recoveries of carbon fiber and glass fiber with high values are reported from their corresponding fiber‐reinforced composites.

Development of Adsorptive Membranes for Selective Removal of Contaminants in Water.

The presence of arsenic and ammonia in ground and surface waters has resulted in severe adverse effects to human health and the environment. Removal technologies for these contaminants include adsorption and membrane processes. However, materials with high selectivity and pressure stability still need to be developed. In this work, adsorbents and adsorptive membranes were prepared using nanostructured graphitic carbon nitride decorated with molecularly imprinted acrylate polymers templated for arsenate and ammonia. The developed adsorbent removed arsenate at a capacity and selectivity similar to commercial ion-exchange resins. Ammonia was removed at higher capacity than commercial ion exchange resins, but the adsorbent showed lower selectivity. Additionally, the prepared membranes removed more arsenate and ammonia than non-imprinted controls, even in competition with abundant ions in water. Further optimization is required to improve pressure stability and selectivity.

Corrosion Resistance and Thermal Conductivity Enhancement of Reduced Graphene Oxide-BaSO4-Epoxy Composites.

The results of studies on the corrosion protectiveness and thermal conductivity of reduced graphene oxide–BaSO4 epoxy composites are reported here. A commercial epoxy resin and reduced graphene oxide (rGO) were blended with a hardening reagent and then mixed with prepared BaSO4–epoxy resin (B–epoxy). The reduced graphene oxide–BaSO4–epoxy composite (rGO–B–epoxy) paste was used to coat the surfaces of Al 7205 alloy and the corrosion and thermal properties were investigated. A corrosion test in a 3.5 wt% synthetic sea water solution showed that the composite coating containing BaSO4 had the best corrosion resistance. Moreover, the rGO–B–epoxy composite showed better protection against corrosion than the epoxy alone. The rGO–B–epoxy composite with 5 wt% BaSO4 had an in-plane coefficient of thermal conductivity of approximately 165.0 W/m K, and the in-plane thermal diffusivity was 71.38 mm2/s. In standard thermal conductivity tests, all three samples had values below 40 W/m K. The rGO–B–epoxy composites showed good surface corrosion protection and in-plane thermal conductivity.

Fluorescence-enhanced Si photodiodes for ultraviolet C rays (UVC) measurements

The ultraviolet C rays (UVC, wavelength λ = 100–280 nm) light generated by a Hg lamp (λ = 254 nm) and UVC light-emitting diodes (LEDs, λ = 265 and 275 nm) was detected using a fluorescence-enhanced silicon photodiode (FE-PD). Ce-doped yttrium aluminum garnet (YAG:Ce), YAG:Pr, YAG:Eu, YAG:Tb, YAG:Cr, Al2O3:Ti, Al2O3:Cr, MgAl2O4:Ti, MgAl2O4:Cr, MgAl2O4:Mn, and commercial fluorescent acrylic resins were tested as phosphor sources to enhance the output signal intensity of the FE-PD irradiated with UVC light. The resulting output signal intensity increased linearly with the UVC light strength, which was adjusted by raising the input current of the UVC LEDs from 0 to 40 mA. The sensitivity of the fabricated UVC detectors, assessed based on the calibration curve slope, varied depending on the phosphor materials. The phosphors effectively enhanced the output signal intensity of the FE-PD, which was up to six times greater than that of the visible and near infrared Si-PD without phosphors; the stronger output signal intensity was achieved using YAG:Tb, YAG:Cr, and a red fluorescent acrylic resin. The visible light emitted by phosphors under UVC irradiation is useful for detecting UVC light by the eye when using FE-PD.

Programmable shape-morphing of rose-shaped mechanical metamaterials

Shape morphing is one of the most attractive functionalities of materials that are desired in many applications, including robotic grippers, medical stents, wearable electronics, and so on. Shape morphing can be implemented by using mechanical metamaterials that combine building blocks with properly designed mechanical or material properties. The design approaches are, however, mostly ad hoc or require materials with special properties. This work proposes two automated design strategies for programmable shape morphing and validates them on structures 3D-printed from a widely available commercial Stereolithography Durable resin. We proposed a so-called rose-shaped metamaterial with reduced stress concentration due to the absence of sharp corners and with a large range of tailorable Poisson’s ratios, from −0.5 to 0.9, governed by a single design parameter. We programmed the shape of the rose-shaped metamaterial sheets aiming at high shape comfortability or uniform effective stiffness. The shape-morphing performance is demonstrated in the linear (0.1% strain) and non-linear (20% strain) deformation regimes, and it agrees well with the tensile test results. Our findings show the potential to develop complex practical metamaterial structures at comparatively low costs.

Impregnation methods for quantitative analyses of the gas diffusion layer in proton exchange membrane fuel cells

Microstructural analysis is central to understand and predict the performance and degradation of proton exchange membrane fuel cell (PEMFC) materials. Advanced electron and x-ray 3-D microscopy methods are needed to characterize the reticulate structures forming the catalyst, gas diffusion layer/ microporous layers. The high-throughput dual beam scanning electron microscope allows the 3-D imaging of such layers with a spatial resolution in the range of a few nm. However, for accurate quantitative analyses, impregnation of the porous sample is required to mitigate artefacts due to milling and pore-through effect, and provide sufficient contrast between the material phases for image segmentation. This study investigates an impregnation method based upon the addition of Cobalt (II) acetylacetonate nanoparticles in an epoxy polymer resin. The results were compared with conventional methods using commercial resins stereology on sections polished by focused ion beam (FIB). The results indicate the appropriateness of the newly proposed method, providing adequate contrast for accurate image segmentation. An Energy Dispersive X-ray (EDX) analysis was included to obtain an information about the composition, which can be used for further improvements of the resin.

A Poly-(ethylene glycol)-diacrylate 3D-Printed Micro-Bioreactor for Direct Cell Biological Implant-Testing on the Developing Chicken Chorioallantois Membrane.

Advancements in biomaterial manufacturing technologies calls for improved standards of fabrication and testing. Currently 3D-printable resins are being formulated which exhibit the potential to rapidly prototype biocompatible devices. For validation purposes, 3D-printed materials were subjected to a hierarchical validation onto the chorioallantoic membrane of the developing chicken, better known as the HET CAM assay. Working along these lines, prints made from poly-(ethylene glycol)-diacrylate (PEGDA), which had undergone appropriate post-print processing, outperformed other commercial resins. This material passed all tests without displaying adverse effects, as experienced with other resin types. Based on this finding, the micro bioreactors (MBR) design, first made of PDMS and that also passed with cell tests on the HET-CAM, was finally printed in PEGDA, and applied in vivo. Following this workflow shows the applicability of 3D-printable resins for biomedical device manufacturing, consents to adherence to the present standards of the 3R criteria in material research and development, and provides flexibility and fast iteration of design and test cycles for MBR adaptation and optimization.

Modeling Propylene Polymerization in a Two‐Reactor System: Model Development and Parameter Estimation

AbstractA series of two reactors is commonly used to produce commercial polypropylene resins to make products with a broad range of microstructures using different feeding policies and/or operating conditions in both reactors. A mathematical model describing the molecular weight distribution (MWD) and yield of polypropylene made with a Ziegler–Natta catalyst in a two‐reactor system is developed in this work. A new methodology to estimate the polymerization kinetic parameters combining the simultaneous MWD deconvolution and analysis of polymer yields in both reactors is also proposed. This pragmatic approach can be applied without knowledge of detailed polymerization rates and is, therefore, very convenient to quantify polymerizations in continuous pilot and/or commercial reactors, where such information is generally not available.

Highly selective separation of Pb(II) with a novel aminophosphonic acid chelating resin from strong-acidic hexa-solute media

The aminophosphonic acid chelating resin of PMAA-P bearing tertiary diphosphonic amine and amide groups, was newly prepared based on poly(methyl acrylate) and ethylenediamine. Due to the extra amide group and 4.64 mmol/g of high grafting molar mass of phosphonic acid groups, PMAA-P was found to combine with Pb(II) through ionic and coordinate bonds to form more stable tridentate and tetradentate coordination modes, resulting in much higher adsorption capacity and selectivity for Pb(II) than the commercial resin S950 even from strongly acidic media (pH 2.0). The maximum adsorption capacity of PMAA-P for Pb(II) was 1.548 mmol/g, exceeding that of S950 by 78.14%. Additionally, as to the hexa-solute system, PMAA-P showed the selectivity order of Pb(II) ≫ Cu(II) > Cd(II) > Zn(II) > Co(II) > Ni(II), with such high separation factors of αHMCsPb(II) as 5.45-+∞ and the high Pb(II) adsorption amount of 1.010 mmol/g, which was 77.19% higher than S950. Moreover, because of the strong replacement effect, the maximum effluent concentration of Ni(II) exceeded 123.60% of its influent concentration in dynamic separation tests. Furthermore, the adsorption amount of Pb(II) remained above 1.241 mmol/g after being regenerated for five cycles. Above all, PMAA-P has great potential in highly selective separation of Pb(II) from strong-acidic media and thus explores an efficient way of treating lead-acid battery wastewaters.

Versatile and Low-Cost Fabrication of Modular Lock-and-Key Microfluidics for Integrated Connector Mixer Using a Stereolithography 3D Printing.

We present a low-cost and simple method to fabricate a novel lock-and-key mixer microfluidics using an economic stereolithography (SLA) three-dimensional (3D) printer, which costs less than USD 400 for the investment. The proposed study is promising for a high throughput fabrication module, typically limited by conventional microfluidics fabrications, such as photolithography and polymer-casting methods. We demonstrate the novel modular lock-and-key mixer for the connector and its chamber modules with optimized parameters, such as exposure condition and printing orientation. In addition, the optimization of post-processing was performed to investigate the reliability of the fabricated hollow structures, which are fundamental to creating a fluidic channel or chamber. We found out that by using an inexpensive 3D printer, the fabricated resolution can be pushed down to 850 µm and 550 µm size for squared- and circled-shapes, respectively, by the gradual hollow structure, applying vertical printing orientation. These strategies opened up the possibility of developing straightforward microfluidics platforms that could replace conventional microfluidics mold fabrication methods, such as photolithography and milling, which are costly and time consuming. Considerably cheap commercial resin and its tiny volume employed for a single printing procedure significantly cut down the estimated fabrication cost to less than 50 cents USD/module. The simulation study unravels the prominent properties of the fabricated devices for biological fluid mixers, such as PBS, urine and plasma blood. This study is eminently prospective toward microfluidics application in clinical biosensing, where disposable, low-cost, high-throughput, and reproducible chips are highly required.

High performance epoxy resin with ultralow coefficient of thermal expansion cured by conformation-switchable multi-functional agent

Epoxy resins with low or negative thermal expansion have been widely searched for a long time owing to their great potential application in aerospace and microelectronics field. For the filler/epoxy resin composites, one key parameter of epoxy resins is to have suitable low coefficient of thermal expansion (CTE) to match with the fillers, however, it still remains a big challenge. In this work, we design and synthesize a new kind of conformation-switchable curing agent that contains dibenzocyclooctadiene (DBCOD) unit, named as cis-diamine-DBCOD. The epoxy resins cured by cis-diamine-DBCOD possess controllable CTE from negative to positive due to the conformational switch of DBCOD units, and the CTE can be tuned by the DBCOD content. We demonstrate the DBCOD units can undergo conformational change from boat to chair conformer with the rise of temperature based on the theoretical calculation and experimental results. Several commercial epoxy resins cured by cis-diamine-DBCOD also exhibit low CTE (around 10 ppm/K), reflecting the universality of the conformation-switch curing agent. Compared with conventional arylamine curing agents, the epoxy resins cured by cis-diamine-DBCOD possess higher Tg (218 °C) from DMA, which has 49 °C increase comparing with the corresponding epoxy resin with similar elongation at break. Meanwhile, the cured epoxy resin has superior mechanical properties, the tensile strength has 46.3 % increase. Therefore, the cis-diamine-DBCOD as a multi-functional conformation-switchable curing agent endows the cured epoxy resin with high dimension stability, thermal and mechanical performances for the specific applications.

The Effect of Glycol Derivatives on the Properties of Bio-Based Unsaturated Polyesters.

The scope of the present study was to prepare fully bio-based unsaturated polyester resins (UPRs) with comparable properties to the commercial formulations. The focus was set on the determination of the optimal prepolymer formulation using the same set of diacids (itaconic and succinic acid) and different diols (propylene glycol, isosorbide and neopentyl glycol) or its equimolar mixtures, keeping the fixed molar ratio of 1:1:2.1 in all feed compositions. Instead of commonly used styrene, bio-based dimethyl itaconate was used as a reactive diluent (RD). The rheology of the obtained resins was studied in detail. The effect of the used diol on structural (FTIR), thermal (DSC), thermomechanical (DMA), and mechanical (tensile) properties was explained. The properties of UPRs were found to be highly dependent on the diol used in the prepolymer formulation. The UPR with an equimolar ratio of propylene glycol and neopentyl glycol was shown to be the most promising candidate to compete with the commercial petroleum-based resins.

Tetrafluorophenylene-Containing Vinylbenzyl Ether-Terminated Oligo(2,6-dimethyl-1,4-phenylene ether) with Better Thermal, Dielectric, and Flame-Retardant Properties for Application in High-Frequency Communication.

In an integrated circuit, signal propagation loss is proportional to the frequency, dissipation factor (Df), and square root of dielectric constant (Dk). The loss becomes obvious as we move to high-frequency communication. Therefore, a polymer having low Dk and Df is critical for copper-clad laminates at higher frequencies. For this purpose, a 4-vinylbenzyl ether phenoxy-2,3,5,6-tetrafluorophenylene-terminated OPE (VT-OPE) resin was synthesized and its properties were compared with the thermoset of commercial OPE-2St resin. The thermoset of VT-OPE shows a higher Tg (242 vs 229 °C), a relatively high cross-linking density (1.59 vs 1.41 mmole cm–3), a lower coefficient of thermal expansion (55 vs 76 ppm/°C), better dielectric characteristic at 10 GHz (Dk values of 2.58 vs 2.75, Df values of 0.005 vs 0.006), lower water absorption (0.135 vs 0.312 wt %), and better flame retardancy (UL-94 VTM-0 vs VTM-1 with dropping seriously) than the thermoset of OPE-2St. To verify the practicability of VT-OPE for copper-clad laminate, a laboratory process was also performed to prepare a copper-clad laminate, which shows a high peeling strength with copper foil (5.5 lb/in), high thermal reliability with a solder dipping test at 288 °C (>600 s), and the time for delamination of the laminate in thermal mechanical analysis (TMA) at 288 °C is over 60 min.

Development of a Custom-Made 3D Printing Protocol with Commercial Resins for Manufacturing Microfluidic Devices.

The combination of microfluidics and photo-polymerization techniques such as stereolithography (SLA) has emerged as a new field which has a lot of potential to influence in such important areas as biological analysis, and chemical detection among others. However, the integration between them is still at an early stage of development. In this article, after analyzing the resolution of a custom SLA 3D printer with commercial resins, microfluidic devices were manufactured using three different approaches. First, printing a mold with the objective of creating a Polydimethylsiloxane (PDMS) replica with the microfluidic channels; secondly, open channels have been printed and then assembled with a flat cover of the same resin material. Finally, a closed microfluidic device has also been produced in a single process of printing. Important results for 3D printing with commercial resins have been achieved by only printing one layer on top of the channel. All microfluidic devices have been tested successfully for pressure-driven fluid flow.

Modified photoresins with tunable refractive index for 3D printed micro-optics

Modern two-photon lithography (TPL) technologies provide convenient methods for 3D printing sub-micron featured structures in photopolymers. TPL is a valuable tool for rapid prototyping of micro-optics, photonic metamaterials, and nanostructures. The ability to tune the optical properties of the resin materials used for TPL greatly expands the capabilities of 3D printing these types of components. Here we couple a sol-gel method of synthesizing and functionalizing titanium dioxide (TiO2) nanoparticles to modify off-the-shelf commercial resins designed for TPL to tune the refractive index of the 3D printable resin. The range of refractive indices expands up to 1.66 at 633 nm which is higher than commercially available, unmodified resins at that wavelength.

A Novel Method to Quantify Self-Healing Capabilities of Fiber-Reinforced Polymers

The present work investigates a novel and practical method to evaluate the healing efficiency of carbon-reinforced polymer composites. The method should be representative of damage occurring during the lifetime of a composite part, should tend to damage the healable matrix mostly and yet be simple and cost-effective to set up. Thus, the capacity to recover low-velocity impact damage has been evaluated via three-point bending flexural tests. Carbon-reinforced composite laminates were produced using HealTech™ T300-TW200-42RW-1250, a commercial healable resin pre-impregnated Torayca T300 3K twill 2 × 2 fabric with an aerial weight of 200 g/m2. Fibers were oriented at ± 45° or at 0°–90°, and the laminates were impacted at different energy levels. Flexural properties of undamaged, damaged, and healed samples were compared, and the healing efficiency was calculated as the ratio of healed and undamaged ultimate flexural strength or modulus. Since matrix healing efficiency is the value to characterize, it was shown that ±45° laminates could be tested without major fiber damage and, thus, provide the best matrix healing efficiency results. Such a method proved to be 1) representative of early-stage damage of composite FRPs often occurring in the form of delamination or matrix microcracking, and 2) a fast and reliable characterization technique requiring the use of a limited amount of material.

Recovery of phenol and acetic acid from glass fibre reinforced thermoplastic resin using catalytic pyrolysis process on ZSM-5 zeolite catalyst and its kinetic behaviour

Glass fibre-reinforced thermoplastic (GFRP) is the composite material of choice for engineers to improve their design, save expenses, and achieve sustainability goals, what leads to generation of a big quantity of GFRP waste (during production or as an end-life-product) that needs to be disposed of safely. In order to valorise GFRP waste, this research aims to recover phenol and acetic acid as high-added value chemical and energy products from the millions of tons of GFRP waste produced annually during the catalytic pyrolysis process. The experiments were performed on glass fibre-reinforced poly(methyl methacrylate)-PMMA (GF/PM) as a common and commercial thermoplastic resin in five stages. In the first stage, the thermal decomposition of the milled feedstock over different percentages of ZSM-5 zeolite catalyst to feedstock in the ranges 0.5–5 wt.% (w/w) was performed using TGA. The generated volatile products from TGA were analysed using TG-FTIR and GC/MS in the second and third stages, respectively. The fourth stage was used to study the kinetic behaviour of catalytic pyrolysis of the feedstock with different catalysts and at different heating conditions using isoconversional models. In the last stage, the experimental thermal decomposition curves were simulated numerically. The results showed that ZSM/GF/PM can decompose significantly in the ranges 320–460 °C. Meanwhile, 2 wt.% of catalyst-to-GF/PM ratio was sufficient to recover more than 48% of phenol, 23% of acetic acid, 19% carbon dioxide compounds at 30 °C/min with high intensity of aromatic benzene. Also, this batch gave a higher kinetic complexity in terms of activation energy in the ranges 100–200 kJ/mol (linear models) and 230–440 kJ/mol (nonlinear models). These results confirm that involvement of 2 wt.% ZSM-5 zeolite catalyst in the pyrolysis of GF/PM has a big impact on the formulated volatile components and their potential upscaling.

Kinetic modeling of adsorption of vanadium and iron from acid solution through ion exchange resins

This study assessed the adsorption process and the reaction kinetics involved in the selective recovery of vanadium from an acid solution containing iron as an impurity. Four commercial resins were studied: Lewatit® MonoPlus TP 209 XL, Lewatit® TP 207, Dowex™ M4195 (chelating resin) and Lewatit® MonoPlus S 200 H (strong cationic exchange resin). To investigate the effect of time on the adsorption process, batch experiments were carried out using the following initial conditions: pH 2.0, 298 K, and a proportion of 1 g of resin to 50 mL of solution. The variation of pH over time was analyzed. Chelating resin released less H+ ions as the adsorption occurred, resulting in a lower drop of pH when compared to S 200 H resin. Ion adsorption by the resins was also evaluated through FT-IR and SEM−EDS before and after the experiments. Among the evaluated kinetic models (pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models), the pseudo-second order model best fits the experimental data of the adsorption of vanadium and iron by all of the four resins. M4195 resin showed the highest recovery of vanadium and the lowest adsorption of iron. Kinetic data, which are fundamental to industrial processes applications, are provided.