Mixture Of Polyurethane Research Articles

Study on dynamic modulus of polyurethane mixture: Impact factors and prediction models

Polyurethane mixture (PUM) is proposed as an innovative and promising paving material due to its superior engineering performance and environmentally-friendliness. This study aims to experimentally investigate dynamic modulus of PUM at various temperatures, loading frequencies and loading strains. Furthermore, prediction models on its dynamic modulus considering factors of temperature, loading frequence as well as their coupling effect are proposed. The results demonstrate that dynamic modulus of PUM approximately varies between 2000 MPa and 19,000 MPa in temperature range of 15–50°C, loading frequency range of 0.1–25 Hz, and loading strains range of 20–100με. Dynamic modulus of PUM at 15°C is approximately 5.62 times higher than that at 50°C. The value at 20 Hz is approximately 2.76 times higher than that at 0.2 Hz. By implementing the analysis of variance (ANOVA) method, it is explored that temperature and loading frequency yield significant impact on dynamic modulus of PUM while loading strain imposes negligible influence on dynamic modulus of PUM. By statistical fitting analysis, dynamic modulus of PUM is linear with temperature and presents power function with loading frequency. Moreover, by considering coupling effect of temperature and loading frequency, prediction model on dynamic modulus of PUM is proposed and verified through experiments. The outcome of this study facilitates design and applications of PUM at different climate conditions and traffic loads.

Green Electromagnetic Interference Shielding Material Based on Thermally Expandable Microspheres.

With the aggravation of electromagnetic pollution, electromagnetic interference (EMI) shielding materials have received enormous attention. However, most of the current EMI shielding materials only focus on the shielding effectiveness (SE), neglecting the electromagnetic pollution brought by secondary reflection. In this work, a method of preparing absorption-dominated EMI shielding materials, which are also called green EMI materials, using thermally expandable microspheres (TEMs) and expanded graphite (EG), is proposed. The expansion of TEMs in the EG/waterborne polyurethane mixture can improve the impedance matching between the composite and air. When the content of TEMs is 5 wt % and the content of EG is 15 wt %, the EMI SE of the sample reaches 38.4 dB, and the average reflection power coefficient of this composite is 0.27, indicating that the material mainly shields electromagnetic waves through absorption. Meanwhile, the prepared material also exhibits good stability, maintaining outstanding EMI SE and low value of reflection power coefficient even after the compression-recovery test.

Study on the Application of Kramers-Kronig Relation for Polyurethane Mixture.

Polyurethane (PU) mixture, which is a new pavement mixture, exhibits different dynamic properties compared to a hot-mixed asphalt mixture (HMA). This paper analyzed whether the Kramers-Kronig (K-K) relation and thermorheologically simple properties applied to the PU mixture. Based on the results, the PU mixture exhibited thermorheologically simple properties within the test conditions. The time-temperature superposition principle (TTSP) was applicable for the PU mixture to construct a dynamic modulus master curve using the standard logistic sigmoidal (SLS) model, the generalized logistic sigmoidal (GLS) model, and the Havriliak-Negami (HN) model. The Hilbert integral transformed SLS and GLS models for the phase angle can accurately fit the measured phase angle data with newly fitted shift factors and predict the phase angle within the viscoelastic range. The core-core and black space diagrams both displayed single continuous smooth curves, which can be utilized to characterize the viscoelastic property of the PU mixture. The K-K relation is applicable for the PU mixture to obtain the phase angle master curve model, storage modulus, and loss modulus from the complex modulus test results with the test temperatures and loading frequencies. The phase angle of the PU mixture at extremely high or low test temperatures cannot be derived from the dynamic modulus data.

Improved sensitivity and ambient light stability of radiochromic plastic dosimeters through composite azo compounds

The aim of this study is to evaluate and compare the dose sensitivity and ambient light resistance of radiochromic plastic dosimeters (RPDs) incorporating mixed azo compound with those incorporating individual azo compounds.RPDs were fabricated using a mixture of polyurethane, leuco dye, initiator, and solvent.In this study, three azo compounds (tartrazine, sunset yellow, and allura red) were incorporated into RPDs either individually or in combination. Thus, we produced five dosimeter types: one original RPD (A) without azo compounds, three RPDs (B, C, D) with individual azo compounds, and one RPD (E) with mixed azo compounds. Initially, to compare dose response and sensitivity, one group of each sample was delivered to doses ranging from 0.2 Gy to 3 Gy with 6 MV photon beams at 600 cGy/min. To assess ambient light resistance, another group was exposed to light for varying durations. Following irradiation and light exposure, optical density (OD) was obtained using a cone-beam optical CT scanner for each group. Wavelength spectra for each sample were acquired using a spectrometer. This study encompassed analysis and comparison of dose response curves, sensitivity, and netOD-time graphs among samples. Additionally, the absorption wavelength spectra of the samples were compared with the light spectrum emitted by a light bulb.The dose response curves were represented by linear functions, with the slope indicating the sensitivity of each sample. The sensitivity for samples A-E were 0.0759, 0.0988, 0.0902, 0.0809, and 0.1013 ΔOD/Gy, respectively. Samples B-E demonstrated increases in sensitivity of 30.1%, 18.8%, 6.5%, and 33.4%, respectively, compared to sample A. Sample E, which incorporated mixed azo compounds, demonstrated the highest sensitivity and remarkable resistance to ambient light. The results suggested that all azo compounds influenced the sensitivity of the RPDs, and that mixed azo compounds does not reduce the sensitivity of the RPDs. The ambient light resistance was dictated by the overlap between the light bulb's wavelength and the azo dyes' absorption range, which for mixed azo compounds spanned widely from 300 nm to 600 nm. The mixed azo compounds, as opposed to a single azo compound, allowed for the absorption of a wider range of light wavelengths, leading to an increased resistance to ambient light.Our study demonstrated that the inclusion of azo compounds enhances the sensitivity of RPDs. Specifically, the use of mixed azo compounds provided the highest sensitivity and exhibited superior resistance to ambient light. This improved performance can be attributed to the broader absorption wavelength spectrum achievable with mixed azo compounds, enabling absorption across a wider range of light wavelengths. These findings highlight the potential utility of mixed azo compounds in the fabrication of RPDs, enhancing their function as highly sensitive and resistant dosimeters to ambient light.

Study on mechanical properties of polyurethane mixtures with different fillers combined with industrial problems

This paper mainly introduces the classification of polyurethane mixtures. To produce new polyurethane composites used in manufacturing, the team researched Polyurethane combined with different composites and showed the mechanical properties of the composites on a chart. When reducing-graphene oxide (GO) and multi-walled carbon nanotubes are mixed with polyurethane, the composite can increase Young’s Modulus to 615 MPa and tensile strength to 657 MPa with a weight reduction of 5%. Glass fibre filled with Polyurethane also provides a fairly Young’s Modulus (over 10000 MPa) with a high weight percent up to 20%. How to increase the content of reduced GO and carbon nanotubes in polyurethane filling will be a problem worthy of further exploration.

Curing Law and Strength-Age Prediction Model of a Dense Polyurethane Mixture under the Influence of Moisture and Temperature

Curing Law and Strength-Age Prediction Model of a Dense Polyurethane Mixture under the Influence of Moisture and Temperature

Design and evaluation of semi self-compacting cold mix polyurethane mixture for steel bridge deck pavement

To enhance the environmental sustainability and pavement performance of steel bridge deck paving, a novel semi self-compacting cold mix polyurethane mixture (CMPU-10) for steel bridge deck paving was specifically designed and evaluated. Herein, this study presents the first comprehensive documentation of the research process involved in the mix design of CMPU-10. Initially, based on the theory of maximum density curve, a gradation with a Talbot index (n) of 0.40 was identified as the preliminary gradation for designing CMPU-10 by void ratio, compressive strength and slump tests. Subsequently, the aggregate grade-by-grade filling test revealed the critical influence of sieve sizes (0.075 mm, 0.6 mm, and 2.36 mm) on the mixture dense degree. From these findings, an in-depth analysis of the effects of aggregate passage under the key sieve on the degree of mixture density, compressive strengths, and flow properties led to the determination of the gradation range of CMPU-10. The optimum binder-aggregate ratio for the median gradation was determined to be 9.2%. Finally, wheel tracking, semi-circular bending (SCB) and freeze-thaw splitting tests showed that the designed CMPU-10 exhibits superior high-temperature stability performance, low-temperature cracking resistance and moisture susceptibility compared to the TAF epoxy asphalt mixture (EA-10). This paper not only provides a new potential low-carbon material for steel bridge deck paving projects, but also establishes a theoretical foundation for the optimization design and promotion polyurethane mixture.

A facile fabrication of an integrated electromagnetic interference shielding material with low electrical resistance based on silver particles/thermoplastic polyurethane composite@copper foil

As microelectronic technology advances, electronic devices have become faster and smaller. The electromagnetic radiation has negative effects on electronic device operation, how to eliminate the electromagnetic radiation has attracted much attention. Copper foil is the most commonly used and effective material for reducing electromagnetic radiation. In practical applications, it is necessary to use adhesive to fix it onto the surface of electronic devices. In this work, an integrated electromagnetic shielding material (AgPs/TPU@Cu hybrid film) was designed and prepared by a facile way, in which the mixture of silver particles (AgPs) and thermoplastic polyurethane (TPU) was cured to form a AgPs/TPU composite film on the surface of copper foil (Cu) by a one-pot heating press processing. The horizontal and vertical electrical resistances of AgPs/TPU composite film decreased to 0.2 Ω and 0.47 Ω at the AgPs loading of 38 wt%, respectively, and the corresponding thermal conductivity reached 0.81 W m−1 K−1. Moreover, the AgPs/TPU@Cu hybrid film at the AgPs loading of 38 wt% exhibited the maximum electromagnetic interference shielding effectiveness (EMI SE) value of 105 dB. This work provides valuable information about EMI shielding technologies for practical electronic applications.

The Investigation of Macro Structure of Composite Material Mixed Rice Husk with Polyurethane as Insulation Material in Fish Cold Storage Boxes


 
 
 
 This research aims to investigate the macro structure of a composite material mixed with rice husk and polyurethane. Determine the material with the best composition to apply to the cooler or fish storage area. The urgency of this research is the application of appropriate technological concepts to support the cold chain system so that the quality of fishermen's catches can be maintained. One of the efforts made is to make composite materials for insulation from a mixture of rice husks and polyurethane with various composition ratios ranging from 1:0.5 to 1:2 polyurethane-rice husks. The results of the research show that each composition obtains different results. From the macro photo test resultsed it shows that the lowest maximum area is in the 1:2 composition, namely 1:2A 14393, 1:2B 5232, 1:2C 4013. From all the test results, the composition is 1:2 is the most feasible material for making fish cooler box insulation because, this composition does not affect the expansion of the polyol and issocianate reaction
 
 
 

Characterization and Performance Evaluation of Magnesium Chloride-Enriched Polyurethane Nanofiber Patches for Wound Dressings.

Wound patches are essential for wound healing, yet developing patches with enhanced mechanical and biological properties remains challenging. This study aimed to enhance the mechanical and biological properties of polyurethane (PU) by incorporating magnesium chloride (MgCl2) into the patch. The composite patch was fabricated using the electrospinning technique, producing nanofibers from a mixture of PU and MgCl2 solutions. The electrospun PU/MgCl2 was then evaluated for various physico-chemical characteristics and biological properties to determine its suitability for wound healing applications. Tensile strength testing showed that the mechanical properties of the composite patch (10.98 ± 0.18) were significantly improved compared to pristine PU (6.66 ± 0.44). Field scanning electron microscopy (FESEM) revealed that the electrospun nanofiber patch had a smooth, randomly oriented non-woven structure (PU - 830 ± 145 nm and PU/MgCl2 - 508 ± 151 nm). Fourier infrared spectroscopy (FTIR) confirmed magnesium chloride's presence in the polyurethane matrix via strong hydrogen bond formation. Blood compatibility studies using coagulation assays, including activated partial thromboplastin time (APTT), prothrombin time (PT), and hemolysis assays, demonstrated improved blood compatibility of the composite patch (APTT - 174 ± 0.5 s, PT - 91 ± 0.8s, and Hemolytic percentage - 1.78%) compared to pristine PU (APTT - 152 ± 1.2s, PT - 73 ± 1.7s, and Hemolytic percentage - 2.55%). Antimicrobial testing showed an enhanced zone of inhibition (Staphylococcus aureus - 21.5 ± 0.5 mm and Escherichia coli - 27.5 ± 2.5 mm) compared to the control, while cell viability assays confirmed the non-cytotoxic nature of the developed patches on fibroblast cells. The study concludes that adding MgCl2 to PU significantly improves the mechanical, biological, and biocompatibility properties of the patch. This composite patch shows potential for future wound healing applications, with further studies needed to validate its efficacy in-vivo.

Cohesion Performance of Tack Coat Materials between Polyurethane Mixture and Asphalt Mixture

Cohesion Performance of Tack Coat Materials between Polyurethane Mixture and Asphalt Mixture

Modeling the Dynamic Properties of the Polyurethane Mixture with Dense Gradation Using the 2S2P1D Model

The polyurethane (PU) mixture is a zero-emission and high-performance engineering mixture that could replace traditional asphalt mixtures for pavement paving. This paper investigated the feasibility of using the 2S2P1D model to characterize the linear viscoelastic (LVE) properties of the PU mixture in comparison to the styrene–butadiene–styrene (SBS)-modified asphalt mixture with identical aggregate gradation and binder content. The PU mixture showed higher prediction precision for dynamic modulus and lower prediction precision for phase angle compared to the SBS-modified asphalt mixture. The seven constants of the 2S2P1D model for the PU mixture differed significantly from those of the SBS-modified asphalt mixture. The PU mixture exhibited higher elastic properties and lower creep properties, but the viscous properties represented by the index of η were different from the loss dynamic modulus, which reflected the mixture’s viscous properties. The index η cannot accurately characterize the viscous properties of the PU mixture. The 2S2P1D model exhibited a higher prediction accuracy than the Sigmoidal Christensen Anderson and Marasteanu (SCM) model and could accurately simulate the LVE properties of the PU- and SBS-modified asphalt mixtures. However, the 2S2P1D model should enhance the creep and dashpot elements to provide a more accurate characterization of the properties of the PU mixture.

Highly sensitive strain sensors based on dispensing technology for human–machine interaction

Flexible strain sensors have stable and sensitive sensing performance under deformation conditions such as pressing, bending, and stretching. However, the preparation process of high-performance strain sensors is still very complex, which also limits the application and production of sensors. At the same time, most sensors are unstable and inefficient, so they cannot meet people’s expectations for high sensitivity and stability. In order to solve the above problems, this paper proposes a resistive strain sensor based on dispensing technology, with carbon black and polyurethane mixture as printing ink. Then, a sensor-sensitive layer with a right-angle serpentine structure is printed directly by air pressure extrusion. The sensor can detect changes at 0.1% strain and withstand 2400 tensile cycles while maintaining a sensitivity of 28.07 in the range of 0%–40%. In addition, the sensor can accurately and stably reflect the changes in different joints of the human body. At the same time, the data glove based on the strain sensor shows great application potential in the fields of gesture recognition and human–machine interaction.

Zwitterionic carbon quantum dots incorporated ultrafiltration membrane for efficient removal of copper ion

Copper, prized for its excellent thermal and electrical conductivity, poses risks when present in wastewater. Treating copper ion-containing wastewater is vital for human and environmental safety. Membrane separation technology offers an eco-friendly and energy-efficient solution. In this study, a mixture of cellulose acetate (CA) and thermoplastic polyurethane (TPU) was used to fabricate the tubular membrane, with quantum dots (QDs) added. Three types of QDs were introduced into the tubular membrane: carbon quantum dots (CQDs), tertiary amine CQDs (TQDs), and zwitterionic CQDs (ZQDs). At pH = 10, copper ions were chelated with sodium dimethyldithiocarbamate (SDDC) at a ratio of SDDC/Cu2+=10 (w/w), signifying a molar concentration (mol.L-1) ratio of SDDC:Cu2+=3:16. This process achieved a 99.8% removal rate of copper ion. The ZQDs-M exhibited high pure water flux of 6,227.4 L.m−2.h−1.bar−1 and 95.4% copper ion-complex rejection rate. The ZQDs-M also demonstrated excellent anti-adhesion properties, with only 4.55% relative fluorescence intensity of E. coli and 34.58% BSA adsorption. The BSA dynamic anti-fouling property of the ZQDs-M was also superior to that of tubular membrane without QDs addition.

Improved interlaminar property of carbon fiber/epoxy composites with polyurethane/RGO core-shell structure fibrous mat

Interlaminar delamination is the most common failure mode of carbon fiber reinforced epoxy (CF/EP) composites, which severely limits their practical application. In this work, reduced graphene oxide (RGO) was decorated on electrospun polyurethane (PU) fibrous veil to produce a hybrid core-shell structure fibrous mat, which was integrated into CF/EP to thoroughly evaluate their influence on the interlaminar fracture toughness and interlaminar shear strength of laminates. The results show that, compared to those of plain composite, the mode I and II interlaminar fracture toughness of the PU/RGO interleaved composites increases by 170 % and 21 %, respectively, while their interlaminar shear strength synchronously increases by 14 %. The improved fracture toughness could be attributed to the plastic deformation of PU and epoxy mixture, crack deflection caused by RGO and pull out and separation behavior of RGO, etc. Henceforth, our hybrid interleaf can be considered as a promising candidate for designing high delamination resistance composites for structural applications.

Improvement of Water Stability of Single-Component Polyurethane Mixture

Improvement of Water Stability of Single-Component Polyurethane Mixture

Energy absorption of polyurethane filled Al 6061 honey comb sandwiched structure

The energy absorption characteristics of composites are developed for applications likely to be subjected to sudden or prolonged impacts. In lightweight applications, the possibilities of Al 6061 composites are being explored with various known materials with similar properties. Three materials of low densities but high strength was combined: hexagonal honeycomb Al 6061 core was sandwiched with polyurethane foam and embedded within two glass fiber-reinforced polymer plates. L-9 orthogonal array Taguchi DOE was adopted for the design of the experiment varying the polyurethane mixture, core height, and face sheet thickness using the three-factor method. From the output of the Taguchi DOE, twenty-seven samples were fabricated. In order to determine the force-displacement relationship for each of the test samples, a three-point bending test was performed on a universal testing machine. Energy absorption (EA) and crushing force (CF) were determined from the force and displacement values. These values were then optimized to minimize the PCF while maximizing EA. Numerical analysis performed correlated with the results from experimental samples after testing. Since energy absorption is a measure of applied force and the resulting displacement on a material, the energy absorption characteristics were discussed.

Study on the Influence Factors of the Dynamic Property of the Polyurethane Mixture with Dense Gradation

Similar to the asphalt mixture, the polyurethane (PU) mixture’s performance and characteristics are dependent on many variables. In this study, six variables, including aggregate gradation (limestone and basalt), aggregate type, PU type, PU content, and curing condition, and several parameter analyzing methods were chosen to determine the effect of variables on the dynamic property, rheological property, and rutting resistance of the PU mixture. The limestone aggregate gradation exhibited a substantial effect on the dynamic property, rheological property, and rutting resistance of the PU mixture; the basalt aggregate gradation exhibited significant influence on the dynamic property and rutting resistance, but a moderate effect on the rheological property. The aggregate type could influence the rheological property and rutting resistance. The slow curing speed of the PU binder decreased the dynamic modulus and rutting resistance but did not influence the phase angle. The rise in PU binder content would only improve the PU mixture’s resistance to rutting. The curing condition and color additive had no impact on the PU mixture’s properties. The generalized logistic sigmoidal (GLS) and Christensen Anderson and Marasteanu model (CAM) models could precisely predict the dynamic modulus and phase angle respectively disregarding the PU mixture features. PUM-10/B exhibited the greatest rutting resistance. The findings will aid in comprehending the properties and influencing factors of the PU mixture as well as in designing the desired mixture.

A facile alternative strategy of upcycling mixed plastic waste into vitrimers

Chemical depolymerization has been identified as a promising approach towards recycling of plastic waste. However, complete depolymerization may be energy intensive with complications in purification. In this work, we have demonstrated upcycling of mixed plastic waste comprising a mixture of polyester, polyamide, and polyurethane through a reprocessable vitrimer of the depolymerized oligomers. Using poly(ethylene terephthalate) (PET) as a model polymer, we first demonstrated partial controlled depolymerization, using glycerol as a cleaving agent, to obtain branched PET oligomers. Recovered PET (RPET) oligomer was then used as a feedstock to produce a crosslinked yet reprocessable vitrimer (vRPET) despite having a wide molecular weight distribution using a solventless melt processing approach. Crosslinking and dynamic interactions were observed through rheology and dynamic mechanical analysis (DMA). Tensile mechanical studies showed no noticeable decrease in mechanical strength over multiple repeated melt processing cycles. Consequently, we have clearly demonstrated the applicability of the above method to upcycle mixed plastic wastes into vitrimers and reprocessable composites. This work also afforded insights into a potentially viable alternative route for utilization of depolymerized plastic/mixed plastic waste into crosslinked vitrimer resins manifesting excellent mechanical strength, while remaining reprocessable/ recyclable for cyclical lifetime use.

The Mechanical Properties Improvement of Polyurethane Rubbers by Using Titanium Oxide and Calcium Carbonate Modifiers (Additives)

The structure of polyurethane and the physico-chemical properties of its components are considered. The most promising modifiers have been selected: TiO2, CaCO3. The features of the preparation of the studied polyurethane mixture, its composition, manufacturing technology and equipment are described in detail. The geometric properties, manufacturing processes and testing methods of samples are presented. The graphical dependencies of the influence of the parameters of sample preparation on their mechanical properties such as hardness, tensile stress at break, Jung s modulus are given. The rational parameters of the technology for the production of samples modified with fillers to give them stable mechanical properties have been set. The maximum proportions of these fillers in polyurethane rubber are limited to 30-35%. It is proved that the addition of TiО2 and CaCО3 to the composition of polyurethane rubbers gives them special properties that allow them to expand the range of their industrial usage.