Combination Of Polyurethane Research Articles

Silica nanoparticle-reinforced polyurethane plastic immobilized with strontium aluminate nanofiller: Ultraviolet protection, superhydrophobicity and photoluminescence

A simple strategy was reported toward a possible industrial preparation of smart plastic materials with persistent afterglow, ultraviolet protection, superhydrophobic properties and photochromism. Nanoparticles of rare-earth doped aluminate (NREA) were embedded into a polyurethane plastic composite. A combination of polyurethane (bulk material), silica nanoparticles (nanofiller), and NREA (luminous agent) was prepared. Achieving a uniform distribution of NREA in a polyurethane fluid allows for the manufactured plastic to be colorless. NREA showed diameters between 12 nm and 26 nm. When excited at 365 nm, the produced photoluminescent polyurethane composite demonstrated an emission band at 519 nm. NREA contents more than 1 % were found to exhibit persistent photoluminescence, whereas pigment concentrations less than 1 % were found to exhibit fluorescence emission. The created plastic concrete exhibited photochromism, as shown by the coloration parameters and photoluminescence spectra, which proved a change in color between transparent during daylight, green under ultraviolet rays, and greenish-yellow in darkness. The static contact angle tests demonstrated effective superhydrophobic properties. Significant improvements were detected ultraviolet protection and photostability. The hardness properties, structural compositions, and morphology of the developed polyurethane plastics were also explored.

Preparation and properties of flame-retardant asphalt containing polyurethane and eco-friendly flame retardants

This paper aims to improve the flame-retardant property of asphalt by modifying asphalt with aluminum trihydrate (ATH), montmorillonite (MMT) and layered double hydroxides (LDHs), which are eco-friendly flame retardants, and polyurethane (PU) was used together with flame retardants. The results showed that the combination of PU and flame retardants could significantly improve the high and low temperature performances of asphalt and the flame-retardant property of asphalt. Among the three flame retardants, LDHs with layered structure shows the best flame-retardant performance owing to its behavior of heat absorption and decomposition. Besides, positive synergistic flame-retardant effect between different flame retardants is observed.

Evaluating Fouling Control and Energy Consumption in a Pilot-Scale, Low-Energy POREFLON Non-Aerated Membrane Bioreactor (LEP-N-MBR) System at Different Frequencies and Amplitudes.

Continual aeration, a fouling control strategy that causes high energy consumption, is the major obstacle in the deployment of membrane bioreactors (MBRs) for wastewater treatment. In recent years, a technology has been developed which adopts mechanical reciprocity for membrane vibration, and it has been proven efficient for membrane scouring, as well as for saving energy: the low-energy POREFLON non-aerated membrane bioreactor (LEP-N-MBR). In this study, a pilot-scale LEP-N-MBR system was designed, established, and operated at various frequencies and amplitudes, and with various membrane models, so as to evaluate energy usage and membrane fouling. The results showed that a slower TMP rise occurred when the frequency and amplitude were set to 0.5 Hz and 10 cm, respectively. Under a suitable frequency and amplitude, the TMP increasing rate of model B (sealed only with epoxy resin) was slower than that of model A (sealed with a combination of polyurethane and epoxy resin). The average specific energy demand (SED) of the LEP-N-MBR was 0.18 kWh·m-3, much lower than the aerated MBR with 0.43 kWh·m-3 (obtained from a previous study), indicating a significant decrease of 59.54% in the SED. However, the uneven distribution of sludge within the membrane tank indicated that the poor hydraulic mixing in the reactor may result in sludge accumulation, which requires further operational optimization. The findings of this pilot-scale study suggest that the LEP-N-MBR system is promising and effective for municipal wastewater treatment with a much lower level of energy usage. More research is needed to further optimize the operation of the LEP-N-MBR for wide application.

Preparation and performance of polyether elastomer with a combination of polyurethane and polytriazole

AbstractPolyether polyurethane elastomers prepared by polyisocyanate N100 and ethylene oxide‐tetrahydrofuran copolymer (PET) were compared to that polytriazole polyethylene oxide‐tetrahydrofuran (PTPET) elastomers prepared by alkynyl‐terminated polyethylene oxide‐tetrahydrofuran (ATPET) and glycidyl azide polymer (GAP) at a comparative molecular weight. The polyether polyurethane (PET‐N100) elastomers turned out to have better mechanical properties than that of PTPET/GAP elastomer. In order to explore the effectiveness of nitrogen‐enriched structures in the field of flame‐retardancy, PET‐N100 and PTPET/GAP elastomers were tested by cone calorimetry. The PET‐N100 elastomer exhibited an inferior performance of flame‐retardancy to that of PTPET/GAP elastomer. Therefore, a modification of the terminal hydroxyl group in GAP with 4,4′‐methylene‐bisphenyl‐isocyanate (MDI) and flame‐retardant diethyl bis(2‐hydroxyethyl) amino methyl phosphonate (DBMAP) was attempted and characterized by FT‐IR, NMR, and gel permeation chromatography. It was found that the synthesized GAP‐MDI‐DBAMP could serve as a novel curing agent for ATPET, which would endow the novel PTPET elastomer a combination of the advantageous properties, that is, the outstanding mechanical properties from PET‐N100 elastomer, favorable flame‐retardancy from PTPET/GAP elastomer and DBAMP. The thermogravimetry analysis/DTG, DSC, tensile strength test, and swelling analysis proved that PTPET/GAP‐MDI‐DBAMP elastomer had excellent thermal stability and mechanical strength.

Combination of polyurethane and polymethyl methacrylate thin films as a microextraction sorbent for rapid adsorption and sensitive determination of neonicotinoid insecticides in fruit juice and tea by ultra high performance liquid chromatography with tandem mass spectrometry

An economical and effective thin film microextraction (TFME) for simultaneous analysis of ten neonicotinoid insecticides and metabolites in fruit juice and tea, was developed based on the combination of polyurethane (PU) and polymethyl methacrylate (PMMA) films as the sorbent followed by ultra high performance liquid chromatography with tandem mass spectrometry. The PU/PMMA composite was evidenced to possess rapid adsorption and strong accumulation towards neonicotinoids compared with the films used alone. A series of parameters were optimized, and the agitation mode, film size, ionic strength, desorption solvent and sample pH were found to dominate the microextraction process rather than the extraction temperature, agitation time and sample volume. The thin films are cost effective and efficient for single use analysis, but still can be reused at least 8 times with no significant loss in performance. The ten neonicotinoids were measured with good recoveries (81.1–107.9%), high enrichment factors (up to 135), low limits of detection (0.001–0.1 µg L−1), and wide linearity range (1–500 µg L−1, r2>0.9981) in fruit juice (apple, lemon, and pomegranate) and tea (green tea and black tea) samples. The proposed method was successfully applied to commercial fruit and tea drinks, and no samples were tested positive on target neonicotinoids. The PU/PMMA based TFME has shown great potential as an alternative to exhaustive extraction techniques for routine screening of trace neonicotinoids in fruit juice and tea by simplifying the analytical procedure, shortening the operation time, and lowering the material expense.

Compression and tension behavior of the prosthetic foam materials polyurethane, EVA, Pelite™ and a combination of polyurethane and EVA: a preliminary study.

Materials with low-strength and low-impedance properties, such as elastomers and polymeric foams are major contributors to prosthetic liner design. Polyethylene-Light (Pelite™) is a foam liner that is the most frequently used in prosthetics but it does not cater to all amputees' limb and skin conditions. The study aims to investigate the newly modified Foam Liner, a combination of two different types of foams (EVA+PU+EVA) as the newly modified Foam Liner in terms of compressive and tensile properties in comparison to Pelite™, polyurethane (PU) foam, and ethylene-vinyl acetate (EVA) foam. Universal testing machine (AGS-X, Shimadzu, Kyoto, Japan) has been used to measure the tensile and compressive stress. Pelite™ had the highest compressive stress at 566.63kPa and tensile stress at 1145kPa. Foam Liner fell between EVA and Pelite™ with 551.83kPa at compression and 715.40kPa at tension. PU foam had the lowest compressive stress at 2.80kPa and tensile stress at 33.93kPa. Foam Liner has intermediate compressive elasticity but has high tensile elasticity compared to EVA and Pelite™. Pelite™ remains the highest in compressive and tensile stiffness. Although it is good for amputees with bony prominence, constant pressure might result in skin breakdown or ulcer. Foam Liner would be the best for amputees with soft tissues on the residual limbs to accommodate movement.

Replication of annulus fibrosus through fabrication and characterization of polyurethane and cellulose nanocrystal composite scaffolds

This study sought to obtain a simple scaffold for annulus fibrosus (AF) repair or replacement using a combination of polyurethane (PU) reinforced with cellulose nanocrystals (CNCs). Composites containing up to 20 wt% CNCs were solvent casted and fabricated into ribbons and radially layered structures to be mechanically tested in tension, compression, creep, and relaxation. Tension and compression testing on swollen composite films and ringed structures, respectively, revealed that the PU 90/10 and PU 80/20 composites had elastic moduli most closely related to the natural AF tissues. Creep and relaxation revealed that the composite materials show a greater percentage of elastic response and longer relaxation times than natural intervertebral disc (IVD) tissues. It was shown that this approach leads to a scaffold that nearly mimics the mechanical properties of natural IVD tissues, while allowing fine tuning of these mechanical properties by varying CNC content and the ringed structure.

A Report of the Impacts of Pollutants on Maritime Operation in Vietnam

The article focuses on synthesis and production of adsorbents to collect oil spills using available and surplus raw materials in agriculture. Research on the manufacture of oil sorbent based on the combination of polyurethane and agricultural by-product is conducted. Nowadays, waste by-products are partly composted, partly used as feed for the remaining cattle that is disposed of in the environment or burned out. This wall is the cause of severe environmental pollution. Therefore, using this waste straw combined with polyurethane to make oil absorbing materials to treat oil pollution at sea is a feasible, scientific and practical option, contributing to minimizing environmental pollution as well as promoting the development of agriculture. Thus, with the current strategy of marine economic development and strong waterway transportation, it will lead to serious environmental pollution if we need specific solutions to solve the problem of neglect. Application of adsorbent material to absorb oil and heavy metals from waste water of transport fleet is part of the strategy of sustainable economic development.

A Report of the Impacts of Pollutants on Maritime Operation in Vietnam

The article focuses on synthesis and production of adsorbents to collect oil spills using available and surplus raw materials in agriculture. Research on the manufacture of oil sorbent based on the combination of polyurethane and agricultural by-product is conducted. Nowadays, waste by-products are partly composted, partly used as feed for the remaining cattle that is disposed of in the environment or burned out. This wall is the cause of severe environmental pollution. Therefore, using this waste straw combined with polyurethane to make oil absorbing materials to treat oil pollution at sea is a feasible, scientific and practical option, contributing to minimizing environmental pollution as well as promoting the development of agriculture. Thus, with the current strategy of marine economic development and strong waterway transportation, it will lead to serious environmental pollution if we need specific solutions to solve the problem of neglect. Application of adsorbent material to absorb oil and heavy metals from waste water of transport fleet is part of the strategy of sustainable economic development.

Triboelectric Nanogenerator Based on Biocompatible and Easily Available Polymer Films

AbstractWe have fabricated robust triboelectric nanogenerators (TENGs) employing different polymer films which are biocompatible and easily available. The combination of polyurethane and PTFE layers is seen to provide the highest TENG parameters with an open circuit peak‐to‐peak output voltage of ∼33.5 V and a current value of 27.4 μA with a gentle tapping force of 0.33 N. The topography of the film surface has been characterized using atomic force microscopy in conjunction with image analysis. We find a very good, albeit non‐linear, correlation between the TENG electrical output and the surface roughness. Our studies do not support any relation between the permittivity of the medium and the TENG output. Employing cellulose acetate and Kapton as the triboelectric layers, we have constructed a simple force sensor, whose output is seen to be highly linear over a large range of force varying from 0.24 to 5.2 N, and a significantly high output of 1.5 V/N.

A functional form-stable phase change composite with high efficiency electro-to-thermal energy conversion

A novel solid-to-solid phase change composite brick was prepared by combination of polyurethane (PU) and pitch-based graphite foam (PGF). The carbonaceous support, which can be used for mass production, not only greatly improves the thermal conductivity but promote electro-to-heat conversion efficiency of organic phase change materials (PCMs). Our composite retained the enthalpy of PCM and exhibited a greatly reduced supercooling temperature. The novel composite was investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The enthalpy of polyurethane has increased about 8.6% after infiltrating into graphite foam. The composite was very stable during thermal cycle test, and the electro-to-heat conversion efficiency achieves to 85% at lower voltages (1.5–1.8V), which can vastly reduce energy consumption. The as-prepared composite was used in a wear layer to test its performance comparing with normal fabric.

Application of Polyurethane Polymer and Assistant Rails to Settling the Abnormal Vehicle-Track Dynamic Effects in Transition Zone between Ballastless and Ballasted Track

This paper describes tests on a transition section between ballasted and ballastless tracks in the Liupanshui-Zhanyi railway in China. The originally unsettled transition zone is exposed to sudden car shaking and a series of track transition problems during train passage. As an example, the influences of polyurethane polymer and a combination of polyurethane and assistant rails to increase track stiffness distribution and track transition decay rates on the dynamic vehicle and track behaviour were investigated. The measured results indicate using only polyurethane and using both polyurethane and assistant rails not only effectively makes the track stiffness change more even but also increases the track decay rate at the target frequencies. These positive effects further reduce the wheel-rail interaction forces and vehicle and rail vertical acceleration, which decreases more when combining polyurethane and assistant rails than when using only polyurethane because the former outperforms the latter for smoothing the track stiffness distribution and increasing the track decay rate. Based on abating wheel-rail impact during the transition from ballasted to ballastless track and improving traffic operation and passenger comfort, combining polyurethane and assistant rails had the greatest effect and may be an effective remedy.

Preliminary Investigations on the Reduction of Foot Pressure Measurement and Muscle Activity with Different Insole Materials

Standing for long periods of time has been recognized as a potential contributor to muscle fatigue. When a person is performing activities in prolonged standing and wearing ineffective material of shoe insole, not only lead to muscle fatigue but can even cause injuries in the long term. The objective of this study is to determine the effects of two types of shoe insole materials; Ethylene Vinyl Acetate (EVA) and a combination of polyurethane (PU) and poron on muscle activity and foot pressure. The analysis of muscle fatigue was performed using surface electromyography (sEMG) while pressure under the foot was measured using FScan device. Results of comparison found that the two types of shoe insole materials showed significant difference (p-value < 0.05) in electromyography signals (µV) in the left and right gastrocnemius muscle while there are significant reductions on the peak pressure measured from the foot pressure measurement. It can be concluded that the combination of PU and poron is an effective material to be used a shoe insole for a person who is exposed to prolonged periods of standing.

Power tiller: Vibration magnitudes and intervention development for vibration reduction

The operators of power tiller are exposed to a high level of vibration originating from the dynamic interaction between the soil and the machine. The vibration from the power tiller is transmitted from the handle to hands, arms and shoulders. In the present study, experiments were conducted in three operational conditions i.e. transportation on farm roads, tilling with cultivator and rota-tilling with rota-vator. The highest vibration values were observed in x-direction in all the experiments. The maximum vibration rms values for x-direction were 5.96, 6.81 and 8.00 ms−2 in tilling with cultivator, transportation and rota-tilling respectively. Three materials were used for intervention development to reduce vibration magnitude. The maximum reduction of 25.30, 31.21 and 30.45% in transportation; 23.50, 30.64 and 20.86% in tilling with cultivator and 24.03, 29.18 and 25.52% in rota-tilling were achieved with polyurethane (PU), rubber and combination of PU and rubber intervention. It was found that the maximum vibration reductions were achieved with the rubber in all three operational conditions. The average exposure time for occurrence of white finger syndrome increased by 28–50% with incorporation of intervention in different operations. Physiological and postural parameters also improved with incorporation of interventions.

Microencapsulation of ammonium phosphate with a polyurethane shell. Part II. Interfacial polymerization technique

Combination of polyurethane and phosphate provides an efficient intumescent flame retardant (FR) system which is not permanent because of the water solubility and migration of phosphate. Microencapsulation has appeared as an alternative way to achieve the permanence of the intumescent flame retardant system. This work deals with the microencapsulation of di-ammonium hydrogen phosphate (DAHP) by polyurethane-urea membrane using an interfacial polymerization method. Chemical and physical structures of the DAHP microcapsules were characterized. According to the thermal degradation analysis, the DAHP microcapsules show characteristics of an intumescent system.