Polyurethane Methacrylate Research Articles

Photo-Crosslinked Polyurethane-Containing Gel Polymer Electrolytes via Free-Radical Polymerization Method.

Using a novel technique, crosslinked gel polymer electrolytes (GPEs) designed for lithium-ion battery applications have been created. To form the photo crosslink via free-radical polymerization, a mixture of polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), vinyl phosphonic acid (VPA), and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP) was exposed to ultraviolet (UV) radiation during the fabrication process. The unique crosslinked configuration of the membrane increased its stability and made it suitable for use with liquid electrolytes. The resulting GPE has a much higher ionic conductivity (1.83 × 10-3 S cm-1) than the commercially available Celgrad2500 separator. A crosslinked structure formed by the hydrophilic properties of the PUA-PUMA blend and the higher phosphate content from BMEP reduced the leakage of the electrolyte solution while at the same time providing a greater capacity for liquid retention, significantly improving the mechanical and thermal stability of the membrane. GPP2 shows electrochemical stability up to 3.78 V. The coin cell that was assembled with a LiFePO4 cathode had remarkable cycling characteristics and generated a high reversible capacity of 149 mA h g-1 at 0.1 C. It also managed to maintain a consistent Coulombic efficiency of almost 100%. Furthermore, 91.5% of the original discharge capacity was maintained. However, the improved ionic conductivity, superior electrochemical performance, and high safety of GPEs hold great promise for the development of flexible energy storage systems in the future.

Thiol‐Ene Photo Crosslinked PUA‐PUMA‐Based Flexible Gel Polymer Electrolyte for Lithium‐Ion Batteries

AbstractCrosslinked polymer films, formed via sol–gel and UV photocrosslinking, serve as gel polymer electrolytes (GPEs) in lithium‐ion batteries. Combining polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP), and 3‐mercaptopropyl trimetoxysilane (MPTMS) yields flexible membranes, enhancing stability and liquid electrolyte compatibility. The resulting GPE displays higher ionic conductivity (1.46 × 10−3 S cm−1) than Celgrad2500, with PUA‐PUMA's hydrophilicity and PETMP's SH groups preventing leakage. GPPF1, the developed GPE, offers improved ionic conductivity, a stable electrochemical window up to 3.8 V, and heightened safety for versatile energy storage systems.

3d Printing of High Viscosity UV-curable Resin for Highly Stretchable And Resilient Elastomer.

Vat photopolymerization prepared elastomers usually exhibit unsatisfied mechanical properties due to their insufficient growth of molecular weight upon UV exposure. Increasing the weight ratio of oligomer in the resin system is an effective approach to enhance the mechanical properties, yet the viscosity of the UV-curable resin increased dramatically which makes it difficult to be used. Here, a linear scan-based vat photopolymerization (LSVP) system which can print high-viscosity resin was carried out to 3D print the oligomer-dominated UV-curable resin via a dual-curing mechanism. Briefly, a polyurethane methacrylate blocking (PUB) oligomer is first synthesized and then mixed with a commercialized bifunctional oligomer, photoinitiator, and primary amine as a chain extender to prepare high-viscosity UV-curable resin for LSVP system. Through thermal treatment, deblocked isocyanate is further crosslinked with a chain extender to construct a highly entangled polymer chain network. The optimal thermal treatment parameters are investigated. Simultaneously, the resilience of the 3D-printed elastomer was evaluated by continuous tensile loading and unloading tests. Subsequently, complex structured elastomers were printed, exhibiting favorable mechanical durability without defects. The results obtained from this work will provide a reference for preparing elastomeric devices with excellent physical properties and expand the application fields of vat photopolymerization. This article is protected by copyright. All rights reserved.

Facile fabrication of high performance hydrophilic anti-icing polyurethane methacrylate coatings cured via UV irradiation

In this article, high performance hydrophilic anti-icing coatings with carboxyl groups were facilely fabricated via UV curing polyurethane methacrylate prepolymers, which were prepared through polyaddition of isophorone diisocyanate (IPDI), poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA) and 2-hydroxypropyl methacrylate (HPMA) gradually in acetone (A series prepolymer) or isobornyl acrylate (IBOA) (B series prepolymer), and finally treated with triethylamine (TEA). The structures of A series prepolymer and the corresponding cured coating were confirmed via various techniques. The anti-icing performance of the cured coatings was investigated by ice freezing delay test, ice adhesion strength test, water contact angle and water absorption tests, and DSC test. Based on the testing results, the anti-icing behavior was defined as the incomplete icing of water on hydrophilic surface to weaken the interface adhesion. The ice adhesion strength firstly decreased as the DMPA content increased. At DMPA content of 5 %, the coating displayed a stable and very low ice adhesion strength of 40 kPa even after 25 times of icing (at −12 °C) and de-icing (at 25 °C) cycling. At even higher DMPA content, the ice adhesion strength improved because of the anchoring effect of the ice. Moreover, when IBOA was used as reactive diluent and participated in the polymerization with the prepolymers, the obtained B series coatings could have much improved mechanical properties, together with low ice adhesion strength. The facile fabrication process, excellent anti-icing performance and adjustable mechanical properties should make the coatings suitable for various purposes.

A biomimetic platform for studying root-environment interaction

AimsMicrostructure plays an important role in biological systems. Microstructural features are critical in the interaction between two biological organisms, for example, a microorganism and the surface of a plant. However, isolating the structural effect of the interaction from all other parameters is challenging when working directly with the natural system. Replicating microstructure of leaves was recently shown to be a powerful research tool for studying leaf-environment interaction. However, no such tool exists for roots. Roots present a special challenge because of their delicacy (specifically of root hairs) and their 3D structure. We aim at developing such a tool for roots.MethodsBiomimetics use synthetic systems to mimic the structure of biological systems, enabling the isolation of structural function. Here we present a method which adapts tools from leaf microstructure replication to roots. We introduce new polymers for this replication.ResultsWe find that Polyurethane methacrylate (PUMA) with fast UV curing gives a reliable replication of the tomato root surface microstructure. We show that our system is compatible with the pathogenic soilborne bacterium Ralstonia solanacearum.ConclusionsThis newly developed tool may be used to study the effect of microstructure, isolated from all other effects, on the interaction of roots with their environment.

Assessment of vinyl acetate polyurethane-based graft terpolymers for emulsion coatings: Synthesis and characterization

Hybrid oligomers composed of polyurethane methacrylate (PUMA) and polyurethane acrylate (PUA) were synthesized by poly addition polymerization of polypropylene glycol (PPG 1000), 2,4- and 2,6-toluen diisocyanate (TDI 80/20) and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was served as the isocyanate blocking agent. The grafting of either PUMA or PUA oligomers to the vinyl acetate monomer was implemented for the first time for improving the properties of the produced PU-co-VAc or (PUPMA or PUPA) terpolymers as new binders for emulsion coating formulations. The synthesized terpolymers were characterized with Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), scanning electron microscope (SEM), gel permeation chromatography (GPC), minimum film forming temperature (MFFT), thermal gravimetric analysis (TGA), Zeta potential and mechanical properties. It has been shown that properties of the terpolymers and their corresponding films were greatly influenced by the grafting of PUMA and PUA at a low concentration level (5 wt%). Cured films of PU based vinyl acetate (PUPMA or PUPA) exhibited higher thermal stability and less weight loss compared to the vinyl acetate copolymer (PVAC). The synthesized PUPMA and PUPA terpolymers revealed enhanced efficiency as binders for emulsion paints in comparison to the PVAC copolymer.

Methacrylate Functionalized MWCNTs/PDMS-Polyurethane Methacrylate UV-Curable Nanocomposites

Polyurethane (PU)-carbon nanotube composites have gained interest in the area of aerospace, automobiles, fuel cells electrical appliances and communication related applications. However, there is still insufficient information on PU-carbon nanotube composites. In this study, hydrophobic and high performance UV-curable nanocomposites were prepared by using surface functionalized multi-walled carbon nanotubes (MWCNT). First, MWCNT were treated with acid solution (HNO3/H2SO4) and then grafted with poly(ethylene glycol) methacrylate (PEGMA) to introduce UV-photopolymerization sites. Different amounts of methacrylate tethered MWCNT and sol–gel precursor or hydrophobic nanosilica were added to PDMS—polyurethane methacrylate based UV-curable formulation and cured by UV irradiation. The composites were also thermally treated (post-cure). The effects of the carbon nanotube, the sol–gel precursor and the hydrophobic nanosilica content on thermal, mechanical and morphological properties of the nanocomposite films were investigated. The addition of the sol–gel precursor and hydrophobic nanosilica increased thermal stability with regard to the base formulation. The addition of MWCNT and silica increased the modulus of the composite from 245 to 318 MPa with regard to the base formulation. Moreover, the thermal decomposition range was increased with addition of the modified MWCNTs. The morphology of the composite films was also carried out by using scanning electron microscopy (SEM). Morphological investigations showed that better dispersion of nanoparticles and performance were achieved when the surface functionalized MWCNTs and hydrophobic silica nanoparticles used together in nanocomposite preparation.

Enhancing the biocompatibility of the polyurethane methacrylate and off-stoichiometry thiol-ene polymers by argon and nitrogen plasma treatment

Our studies focused on improving the biocompatibility properties of two microfluidic prototyping substrates i.e. polyurethane methacrylate (PUMA) and off-stoichiometry thiol-ene (OSTE-80) polymer by Ar and N2 plasma treatment. The contact angle (CA) measurement showed that both plasma treatments inserted oxygen and nitrogen moieties increased the surface energy and hydrophilicity of PUMA and OSTE-80 polymer which corresponded to an increase of nitrogen to carbon ratios (N/C), as measured by XPS, to provide a conducive environment for cell attachments and proliferation. Under the SEM observation, the surface topography of PUMA and OSTE-80 polymer showed minimal changes after the plasma treatments. Furthermore, ageing studies showed that plasma-treated PUMA and OSTE-80 polymer had stable hydrophilicity and nitrogen composition during storage in ambient air for 15days. After in vitro cell culture of human umbilical vein endothelial cells (HUVECs) on these surfaces for 24h and 72h, both trypan blue and alamar blue assays indicated that PUMA and OSTE-80 polymer treated with N2 plasma had the highest viability and proliferation. The polar nitrogen moieties, specifically amide groups, encouraged the HUVECs adhesion on the plasma-treated PUMA and OSTE-80 surfaces. Interestingly, PUMA polymer treated with Ar and N2 plasma showed different HUVECs morphology which was spindle and cobblestone-shaped respectively after 72h of incubation. On the contrary, a monolayer of well-spread HUVECs formed on the Ar and N2 plasma-treated OSTE-80 polymers. These variable morphologies observed can be ascribed to the adherence HUVECs on the different elastic moduli of these surfaces whereby further investigation might be needed. Overall, Ar and N2 plasma treatment had successfully altered the surface properties of PUMA and OSTE-80 polymer by increasing its surface energy, hydrophilicity and chemical functionalities to create a biocompatible surface for HUVECs adhesion and proliferation.

Ageing properties of polyurethane methacrylate and off‐stoichiometry thiol‐ene polymers after nitrogen and argon plasma treatment

ABSTRACTProprietary mixture of polyurethane methacrylate (PUMA) and off‐stoichiometry thiol‐ene (OSTE‐80) are evaluated as two possible polymeric substrates to prototype microfluidic biochips. Because of their lack of biocompatibility, PUMA and OSTE‐80 are modified by argon (Ar) or nitrogen (N2) plasma treatment to introduce nitrogen moieties that are highly polar and conducive for cell attachment and growth. XPS and water contact angle measurement show that these nitrogen groups are relatively stable in the plasma‐treated PUMA and OSTE‐80 in spite of the hydrophobic recovery and volatilization of nitrogen moieties during air ageing for 15 days. This stability can be attributed to their high degree crosslinking that is reflected by the increase of elastic modulus of PUMA and OSTE‐80 during their air ageing. These results show that Ar and N2 plasma‐treated PUMA and OSTE‐80 possess the necessary physical and chemical properties to be evaluated further to develop microfluidic biochips for biological applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44107.

Impact of oxygen-permeable mold on fabrication of microchannels with ultraviolet curable materials

In this work, effect of oxygen diffusion on curing of materials which are sensitive to ultra violet light (UV) in fabrication of microchannels using micromolds with oxygen permeability is investigated. The effects of physical boundary conditions of mold on microfabrication of polymeric arrays of high aspect-ratio microchannels in presence of oxygen inhibition and under variable UV intensity and dose are studied analytically and experimentally. Polydimethylsiloxane (PDMS) as the oxygen-permeable material and polyurethane methacrylate (PUMA) as the UV-curable substrate are selected for experiments. It is shown that for a wide range of exposure intensity and dose, a thin layer of PUMA resin with thickness of a few micrometers in contact with the mold remains uncured and inhibited by high concentration of oxygen molecules while the overall curing rate is reduced by about tenfold for PDMS compared to impermeable silicon mold. The direct impact of presence of high concentration of oxygen in both of mold and resin during UV curing and due to insufficient exposure dose and intensity is a considerable alteration in geometries of manufactured microstructures. The obtained results are crucial for method of use of micromolding and evaluation of fidelity of the replicated microstructures with the proposed design in terms of verticality of the walls and details of the transferring patterns that are important to microfluidic applications.

Fabrication of UV-Curing Polyurethane Methacrylate (PUMA) Microchannel and Fluidics Interconnect for Microfluidics Applications

Microfluidics platform offers a great advantage in bio-sensing and clinical diagnostics miniaturization. The requirement of inexpensive and rapid-prototyping materials are essential in microfluidics device commercialization. This paper presents rapid prototyping of UV-curing Polyurethane Methacrylate (PUMA) microchannel from the Polydimethlsiloxane (PDMS) mold. Two techniques in PUMA microchannel UV-curing rapid prototyping have successfully demonstrated in this work. The first technique utilized thin film transparency sheet as PUMA resin top surface cover in facilitating PUMA UV-curing. The second method exploited confined nitrogen gas environment in Pyrex dish chamber in expediting PUMA curing under UV light exposure. In this work, two different approaches of fluidic interconnect tubings for PUMA microchannel inlet and outlet are also presented. Reversible bonding techniques using corona discharge treatment are utilized for bonding of PUMA microchannel and fluidic interconnect with PUMA, silicon, glass and PDMS substrate. Accomplishment of preliminary fluid flow testing using PUMA microchannel proved its capability for microfluidics applications.

Polyurethane/Poly(2-(Diethyl Amino)Ethyl Methacrylate) blend for drug delivery applications

A pH-sensitive blend of polyurethane (PU) and poly(2-(diethyl amino)ethyl methacrylate (PDEA) with good film-forming capacity was prepared from the corresponding aqueous dispersions. The polymer matrix was first characterized by using FTIR, DSC, water vapor transmission and water swelling capacity at different pHs. The drug release profile of films was evaluated using a vertical Franz Cell and theophylline as model drug. The water swelling degree increases from 54 to 180% when the pH of the medium is changed from 6 to 2, demonstrating the pH-responsive behavior of the film. The in-vitro release studies indicate that an anomalous transport mechanism governs the theophylline release.

Consideration of Nonuniformity in Elongation of Microstructures in a Mechanically Tunable Microfluidic Device for Size-Based Isolation of Microparticles

This paper presents an investigation of the nonlinearity behavior in deformation that appears during the linear stretching of the elastomeric microstructures in a pillar-based microfilter. Determining the impact of the nonuniformity in strain on the geometry and performance of such a planar device under in-plane stretch is the motivation for this study. A semiempirical model is used to explain the physical strain-stress behavior from the root to the tip of the micropillars in the linear arrays in the device. For microfabrication of the device, the main substrate is elastomeric polyurethane methacrylate, which is utilized in an ultraviolet-molding method. Optical imaging and scanning electron microscopy were used to evaluate the deformation of the microstructures under different loading conditions. It was demonstrated that by applying mechanical strains of <;20% (ΔL/L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> ) on the elastomeric device using a modified syringe pump, the spacing of the pillars is increased effectively to about three times the size of the initial setting of 5.5 μm, which corresponds to a strain of above 180% in the absence of nonuniformity effects. This simple yet interesting behavior can be exploited to rapidly adjust a microfluidic device for application to the separation of microbeads or blood cells, which would normally require the geometrical redesign and fabrication of a new device.

Exploiting the oxygen inhibitory effect on UV curing in microfabrication: a modified lithography technique.

Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity.

A pillar-based microfilter for isolation of white blood cells on elastomeric substrate.

Our goal is to design, fabricate, and characterize a pillar-based microfluidic device for size-based separation of human blood cells on an elastomeric substrate with application in the low-cost rapid prototyping of lab-chip devices. The single inlet single outlet device is using parallel U-shape arrays of pillars with cutoff size of 5.5 μm for trapping white blood cells (WBCs) in a pillar chamber with internal dead-volume of less than 1.0 μl. The microstructures are designed to limit the elastomeric deformation against fluid pressures. Numerical analysis showed that at maximum pressure loss of 15 kPa which is lower than the device conformal bonding strength, the pillar elastomeric deformation is less than 5% for flow rates of up to 1.0 ml min(-1). Molding technique was employed for device prototyping using polyurethane methacrylate (PUMA) resin and polydimethylsiloxane (PDMS) mold. Characterization of the dual-layer device with beads and blood samples is performed. Tests with blood injection showed that ∼18%-25% of WBCs are trapped and ∼84%-89% of red blood cells (RBCs) are passed at flow rates of 15-50 μl min(-1) with a slight decrease of WBCs trap and improve of the RBCs pass at higher flow rates. Similar results were obtained by separation of mixed microspheres of different size injected at flow rates of up to 400 μl min(-1). Tests with blood samples stained by fluorescent gel demonstrated that the WBCs are accumulated in the arrays of pillars that later end up to blockage of the device. Filtration results of using elastomeric substrate present a good consistency with the trend of separation efficiencies of the similar silicon-based filters.

Non‐isocyanate synthesis and application of telechelic polyurethanes via polycondensation of diurethanes obtained from ethylene carbonate and diamines

AbstractAliphatic polyurethanes could be obtained in high yield via a non‐isocyanate method based on the self‐polycondensation of dihydroxyurethanes obtained by the reaction of diamines and ethylene carbonate. The polycondensation under a N2 atmosphere yielded [6,2]polyurethane with a Mn value of 5300 in 87% yield. Two‐step polycondensation, consisting of the polycondensation under a N2 atmosphere followed by that under reduced pressure, was effective to improve the yield and the molecular weight up to 90% and 10,000, respectively. Although the second polycondensation step at 180 °C was accompanied by formation of urea groups, this side reaction was relatively suppressed at 150 °C. The resulting polyurethane having hydroxyl groups at both of the end groups was converted to polyurethane methacrylate via a reaction with glycidyl methacrylate, and the polyurethane methacrylate served as a crosslinker for radical polymerization of methyl acrylate. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

A new UV-curing elastomeric substrate for rapid prototyping of microfluidic devices

Rapid prototyping in the design cycle of new microfluidic devices is very important for shortening time-to-market. Researchers are facing the challenge to explore new and suitable substrates with simple and efficient microfabrication techniques. In this paper, we introduce and characterize a UV-curing elastomeric polyurethane methacrylate (PUMA) for rapid prototyping of microfluidic devices. The swelling and solubility of PUMA in different chemicals is determined. Time-dependent measurements of water contact angle show that the native PUMA is hydrophilic without surface treatment. The current monitoring method is used for measurement of the electroosmotic flow mobility in the microchannels made from PUMA. The optical, physical, thermal and mechanical properties of PUMA are evaluated. The UV-lithography and molding process is used for making micropillars and deep channel microfluidic structures integrated to the supporting base layer. Spin coating is characterized for producing different layer thicknesses of PUMA resin. A device is fabricated and tested for examining the strength of different bonding techniques such as conformal, corona treating and semi-curing of two PUMA layers in microfluidic application and the results show that the bonding strengths are comparable to that of PDMS. We also report fabrication and testing of a three-layer multi inlet/outlet microfluidic device including a very effective fluidic interconnect for application demonstration of PUMA as a promising new substrate. A simple micro-device is developed and employed for observing the pressure deflection of membrane made from PUMA as a very effective elastomeric valve in microfluidic devices.

New IPN for high-tech applications: synthesis and functional properties

Resins based on cyanates and polymethacrylates, possessing interesting thermal, mechanical, fire-retardant and other functional properties, can be easily prepared. They can serve as ideal low-density matrices for composites, offering attractive properties for advanced aeronautical applications. This work discusses various routes to prepare different interpenetrating polymer networks (IPNs) based on cyanate esters or isocyanurate urethane methacrylate networks: a hybrid network comprising flexible segments of polybutylene-glycol-adipate (PBGA), a semi-IPN containing flexible crystalline linear polyurethane (CPU) based on PBGA, a full IPN possessing flexible polyurethane methacrylate (PUMA) based on PBGA, and a full IPN linked with flexible silicone-based isocyanurate urethane methacrylate (IsUMA). We will comment on the above-mentioned systems and compare their thermo-mechanical, mechanical and fire-retardant properties.

A new USP Class VI-compliant substrate for manufacturing disposable microfluidic devices

As microfluidic systems transition from research tools to disposable clinical-diagnostic devices, new substrate materials are needed to meet both the regulatory requirement as well as the economics of disposable devices. This paper introduces a UV-curable polyurethane-methacrylate (PUMA) substrate that has been qualified for medical use and meets all of the challenges of manufacturing microfluidic devices. PUMA is optically transparent, biocompatible, and exhibits high electroosmotic mobility without surface modification. We report two production processes that are compatible with the existing methods of rapid prototyping and present characterizations of the resultant PUMA microfluidic devices.

Microfabricating high-aspect-ratio structures in polyurethane-methacrylate (PUMA) disposable microfluidic devices

We recently reported a new UV-curable polyurethane-methacrylate (PUMA) resin that has excellent qualities as a disposable microfluidic substrate for clinical diagnostic applications. This article discusses strategies to improve the production yield of PUMA chips that contain dense and high-aspect-ratio features, which presents unique challenges in demolding and bonding steps. These fabrication improvements were deployed to produce a microfiltration device that contained closely spaced and high-aspect-ratio columns, suitable for retaining and concentrating cells or beads from a highly diluted suspension.