Properties Of Polyurethane Research Articles

Preparation and Properties of Translucent Suspension Chain Polyurethane With a Broad Damping Temperature Range at Near Room Temperature

ABSTRACTDeveloping a viscoelastic polymer damping material with a broad range of effective damping temperatures at room temperature and multiple functionalities has been a prominent research focus, possessing significant economic and social importance. Herein, the elastic main chain was synthesized using branched polyester polyol (DPH) and isophorone diisocyanate (IPDI). The suspension chain prepolymer was fabricated with monohydroxy long alkyl‐chain hydroxy silicone oil (OH‐PDMS) and IPDI. Translucent and damping branched polyurethane viscoelastic materials (BPUs) were prepared by reacting the elastic main chain and the suspension chain prepolymer with the cross‐linking agent trimethylolpropane (TMP). The influences of introducing suspension chains and their content within the polyurethane structure on the damping, mechanical, dynamic mechanical, thermomechanical, and water resistance properties of the polyurethane were comprehensively investigated. The experimental results indicate that the damping factor (Tanδmax) of polyurethane decreases from 1.17 to 0.91 with the addition of suspension chain. Then, with the increase of suspension chain content, the damping factor (Tanδmax) decreases slightly. The damping factor (Tanδmax) still reaches 0.84 with 66% suspension chain content. At the same time, the effective damping temperature range gradually increases from 56.4°C to 119.4°C. The glass transition temperature decreased from 58.9°C to 27.8°C, enhancing the damping performance at room temperature. It was discovered that introducing suspension chains with the SiOSi structure would delay the decomposition of soft segments and enhance heat resistance. Additionally, when the content of the suspension chain is raised to 66%, the hydrophobicity of polyurethane reaches the maximum level and the elongation at break attains 423% ± 12%.

Effect of Molybdenum Bisulfide (MoS2) Particle Size on Tribological and Vibration Reduction Properties of Thermoplastic Polyurethane

The incorporation of lubricating filler can improve the self-lubricating properties of polymers and mitigate friction-induced vibration under harsh conditions. However, filler performances significantly vary depending on its size. In this study, molybdenum bisulfide (MoS2) particles of various sizes were utilized as lubricating additives to reinforce thermoplastic polyurethane (TPU). The results showed that an appropriate decrease in the particle size of MoS2 facilitated more efficient stress transfer from the polymer to the particle due to strengthened interfacial interaction, resulting in improved mechanical properties of the reinforced TPU composites. Additionally, the adsorption property of the MoS2 particle improved, extending the duration of the MoS2 tribofilm. These beneficial phenomena endow TPU composites with excellent tribological and frictional vibration reduction properties, with the 500 nm MoS2 presenting the best reinforcing effect. However, further reduction in particle size caused particle agglomeration, which adversely affected the mechanical and self-lubricating properties of the composite and eventually reduced the frictional vibration reduction properties. The findings obtained herein provide a valuable reference for developing a novel polymer with excellent friction and vibration reduction properties.

Sustainability of Nonisocyanate Polyurethanes (NIPUs)

This work discusses the synthesis and properties of nonisocyanate polyurethanes (NIPUs) as an environmentally friendly alternative to traditional polyurethanes. NIPUs are made without the use of toxic isocyanates, reducing the environmental impact and safety concerns associated with their production. However, their synthesis reactions often require longer time and more energy to be completed. The sustainability of NIPUs is considered from various angles; the main methods for the synthesis of NIPUs, including rearrangement reactions, transurethanization, and ring-opening polymerization of cyclic carbonates with amines, are examined. Another part focuses on renewable sources, such as vegetable oils, terpenes, tannins, lignins, sugars, and others. The synthesis of waterborne and solvent-free NIPUs is also discussed, as it further reduces the environmental impact by minimizing volatile organic compounds (VOCs) and avoiding the use of harmful solvents. The challenges faced by NIPUs, such as lower molecular weight and higher dispersity compared to traditional polyurethanes, which can affect mechanical properties, were also addressed. Improving the performance of NIPUs to make them more competitive compared to conventional polyurethanes remains a key task in future research.

Properties of thermoplastic polyurethane synthesized from bio‐based diisocyanate for FDM 3D printing

AbstractBio‐based polymeric materials have recently gained popularity due to their unique properties, including environmental friendliness, biodegradability, and sustainability. In this study, the bio‐based TPUs were successfully synthesized by one‐shot polymerization method, utilizing 100% bio‐based polytrimethylene ether glycol (PO3G) as polyols, 71% bio‐based 1,5‐pentamethylene diisocyanate (PDI) as isocyanates, and 100% bio‐based 1,4‐butanediol BDO as chain extenders. The as‐prepared TPUs, which contained up to 92% bio‐based material were investigated using a variety of analytical methods, including morphological investigations, mechanical testing, thermal analysis, rheological behavior, docking analysis, and cytotoxicity studies. For PPB 3 (1:3:2), PPB 4 (1:4:3), PPB 5 (1:5:4), and PPB 7 (1:7:6), the initial modulus values were 78, 151, 194, and 314 GPa, and the shore‐A hardness values were 92, 93, 93, and 94. Additionally, a notable variation in the degree of phase separation (DPS) of 0.575, 0.647, 0.716, and, 0.738 between hard segment (HS) and soft segment (SS) was noticed among synthesized bio‐based TPUs and an increase in DPS with higher molar ratios corresponded to a higher content of HS. Besides, the bio‐based TPU proved outstanding cell viability results, representing its potential appropriateness for various biomedical applications. Eventually, docking simulations were shown in silico to evaluate the interaction of bio‐based TPU with the DNA gyrase enzyme. Furthermore, the results of bio‐based TPUs demonstrated excellent applications in the production of 3D printing using FDM. We effectively prepared 3D printing to provide a viable answer to environmental concerns.

Preparation and performance study of low heat storage flame retardant polyurethane for coal mines

In order to meet the requirements for the use of polyurethane for reinforcement in mines, the synthesis temperature of polyurethane needs to be lowered, and the flame-retardant and mechanical properties of polyurethane should also be considered comprehensively. Factors affecting the synthesis temperature of polyurethanes are investigated, low heat storage polyurethanes that meet the temperature requirements for use in plugging crushed coal bodies in coal mines are formulated, and the synthesized polyurethanes are characterised for their flame retardant properties by FTIR, SEM, TG-FTIR and CONE experiments. It was found that in this paper, a new type of polyurethane for coal mines was formed by flame retardant modification of polyurethane by adding nano-system flame retardant and phosphorus-system flame retardant, and the synthetic reaction temperature of the material could reach as low as 51.2 °C, and the pyrolysis onset temperature was increased to 286 °C. The experimental results show that the flame retardant property of this synthetic polyurethane has been significantly improved, and the heat accumulation effect of the synthesis process on the surrounding coal body has been greatly reduced. The physical properties and thermal stability of this synthetic polyurethane in the grouting process meet the safety requirements for use in underground coal mines.

Computer Simulation of Triazole-Modified Urethane Segments

The focus is on the development of siloxane-urethane block copolymer matrices for additive manufacturing applications, including soft robotics. Molecular dynamics simulations compare classical urethane segments with the triazole-modified ones, revealing temperature-dependent behaviors in their conformational structures. The results suggest the potential for tailoring the mechanical properties of polyurethanes through molecular modification, which is crucial for optimizing additive manufacturing processes. Further research could advance material design for customizable objects with desired mechanical response.

Properties of polyurethane foam/natural fibre composite for air conditioning insulation

ABSTRACT This study focuses on the fabrication of a biocomposite with insulating properties suitable for application in refrigeration pipe systems. The objective of this study was to utilise coconut husk and rice husk in a 1:1 ratio as reinforcement for flexible polyurethane foam. Biocomposites were made using hand mixing and casting technique reinforcement ratios of 5%, 10%, 15%, 20%, and 25% weight ratios from reinforcement husks. A thermal resistivity test, along with tensile test and water absorption measurements as a function of fibre content, was conducted according to ASTM standards. The study demonstrated that incorporating coconut and rice husks as reinforcement in polyurethane foam significantly improved the tensile properties of the composite material. The composite reinforced with 25% weight has been found to have highest tensile stress. In contrast, the thermal resistivity is observed to decrease as the fibre content is increased. A maximum thermal resistivity at 5% wt was found from the reinforcement. On the other hand, the amount of water absorption of the polymer compound increases with the increase in weight percentage of natural fibres. Based on these results, Flexible polyurethane foam reinforced with coconut husks and rice husks shows a promising solution for use as insulation for air conditioning pipes.

Introducing the mineral powder to strengthen polyurethane grouting materials for crack repair of asphalt pavements

Cracking in asphalt pavement may lead to structural distress while existing crack repair materials have significant shortcomings in terms of cost and construction efficiency. This study incorporates mineral powder into the polyurethane grouting materials to provide a more economical and durable solution for repairing cracks in asphalt pavement. The results of bonding and tensile tests show that excessive mineral powder may deteriorate the mechanical properties of polyurethane grouting materials, which is caused by the agglomeration of mineral powder observed by the microscale characterization. Characterization tests indicate that ultraviolet exposure results in the evolution of the chemical components and thermal stability of polyurethane grouting materials, subsequently causing the degeneration in the mechanical properties. The addition of mineral powders was found to increase the tensile strength of polyurethane grouting materials after Ultraviolet aging by 12 %, while the elongation at break measured in tensile tests remained essentially unchanged. The results of the splitting test, bending test, and immersion Marshall test prove the enhanced low-temperature property and moisture resistance of mineral powder-modified polyurethane grouting materials as compared to the styrene-butadiene-styrene emulsified asphalt. The economic analysis shows that this study presents a practical approach to cost-effective asphalt pavement crack repair, offering insights for enhancing the durability of asphalt pavements.

Effects of Isocyanate Structure on the Properties of Polyurethane: Synthesis, Performance, and Self-Healing Characteristics.

Polyurethane (PU) plays a critical role in elastomers, adhesives, and self-healing materials. We selected the most commonly used aromatic isocyanates, 4,4'-methylene diphenyl diisocyanate (MDI) and tolylene-2,4-diisocyanate (TDI), and the most commonly used aliphatic isocyanates, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane-4,4'-diisocyanate (HMDI), as raw materials, combined with polytetramethylene ether glycol (PTMG) and 1,4-butanediol (BDO) to successfully synthesize five PU materials. The effects of isocyanate structure on polymerization rate, hydrogen bonding, thermal properties, phase separation, wettability, self-healing performance, adhesion, and mechanical properties were systematically investigated. The results show that isocyanates with higher symmetry facilitate hydrogen bonding, but excessive flexibility and crystallinity may inhibit its formation. MDI-based PU exhibits the highest hydrogen bonding index (HBI) of 4.10, along with the most distinct phase separation and the highest tensile strength of 23.4 MPa. HMDI-based PU demonstrates the best adhesion properties, with the highest lap shear strength of 7.9 MPa, and also exhibits excellent scratch healing ability. IPDI-based PU shows good self-healing performance, recovering 88.7% of its original tensile strength and 90.6% of its original lap shear strength after heating at 80 °C for 24 h. Furthermore, all the samples can be reprocessed by melt or solution methods, showing excellent recyclability.

Polyurethanes and Their Biomedical Applications.

The tunable mechanical properties of polyurethanes (PUs), due to their extensive structural diversity and biocompatibility, have made them promising materials for biomedical applications. Scientists can address PUs' issues with platelet absorption and thrombus formation owing to their modifiable surface. In recent years, PUs have been extensively utilized in biomedical applications because of their chemical stability, biocompatibility, and minimal cytotoxicity. Moreover, addressing challenges related to degradation and recycling has led to a growing focus on the development of biobased polyurethanes as a current focal point. PUs are widely implemented in cardiovascular fields and as implantable materials for internal organs due to their favorable biocompatibility and physicochemical properties. Additionally, they show great potential in bone tissue engineering as injectable grafts or implantable scaffolds. This paper reviews the synthesis methods, physicochemical properties, and degradation pathways of PUs and summarizes recent progress in applying different types of polyurethanes in various biomedical applications, from wound repair to hip replacement. Finally, we discuss the challenges and future directions for the translation of novel polyurethane materials into biomedical applications.

Curing kinetics of block copolymerization thermoset polyurethane by non‐isothermal DSC method

AbstractPolyurethanes consist of hard and soft segments, with the hard segments typically comprising blocks containing isocyanate groups, while the soft segments often consist of chains terminated with hydroxyl groups. The hard segments contribute to the mechanical properties of polyurethanes, while the soft segments provide elasticity and flexibility. The essence of curing lies in the mixing of hard and soft segments and subjecting the system to high temperatures. The curing kinetics of PEG/PCL/IPDI/N100 in‐situ block copolymers were investigated using dynamic isothermal differential scanning calorimetry (DSC). Key curing parameters were obtained from non‐isothermal DSC curves, and these parameters were incorporated into an n‐order reaction model to determine the reaction type and apparent activation energy, thus deriving the reaction equation. The curing kinetics of PEG/PCL/IPDI/N100 in‐situ block copolymers follows an n‐th order autocatalytic reaction, where n is 1, and the activation energy is approximately 52.79 kJ/mol. Based on the reaction equation, the curing process conditions, namely the initial curing temperature (Ti), the peak exothermic temperature (Tp), and the finishing temperature (Tf), were deduced. Studying the curing kinetics of thermosetting polyurethanes can deepen our understanding of the interactions and reaction mechanisms between reactants under different conditions, thereby enhancing our grasp of the curing process. Furthermore, research into curing kinetics can provide a basis for optimizing preparation processes.

Effects of soft segment molecular weight on the properties of recyclable polyurethanes with low‐temperature multiple shape memory

<scp>Effects</scp> of soft segment molecular weight on the properties of recyclable polyurethanes with low‐temperature multiple shape memory

CO2-based polyurethane elastomers with enhanced mechanical and tunable room-temperature damping performances

Elastomers provide excellent damping performance owing to their unique viscoelasticity, which are widely used as vibration and noise reduction materials. However, conventional rubber-based elastomers with a low glass transition temperature (Tg) and narrow damping range are difficult to adapt to room-temperature conditions. Additionally, most of petroleum-based elastomers hinder the sustainable development. In this work, a series of novel polyurethane elastomers was synthesized using carbon-fixed CO2-based polycarbonate propylene diol (PPCD). The impact of hard segment (HS) content on the thermal, mechanical, and damping properties of CO2-based polyurethane (PU) was comprehensively investigated. Increasing the HS content from 16 % to 44 % increased the Tg from −3.8 °C to 21.7 °C, covering the entire damping range at room temperature with an adjustable damping performance. Furthermore, the tensile strength increased from 7.2 MPa to 27.0 MPa. The synthesis of CO2-based PU can propel the utilization of PU in damping applications, enabling sustainable advancement of the PU industry.

Synthesis and optical properties of fluorinated polyurethaneimide electro-optic waveguide polymer

Fluorinated polyurethaneimide (PUI) electro-optic waveguide polymer with polyurethane and polyimide chain segment structures was synthesized by stepwise polymerization using the synthesized amino ester oligomer pu and imide oligomer pi as monomers. Since the main chain structure of the synthesized PUI had the functionality of both polyurethane and polyimide chain segment structures, it combines the excellent thermal and film-forming properties of polyurethanes and polyimides, as well as lower optical transmission loss in the near-infrared wavelength band. The glass transition temperature (Tg) of PUI was 182 °C, and the 5% heat loss decomposition temperature was 325 °C. The PUI had good optical properties with an optical propagation loss of 1.10 dB/cm and an electro-optic (EO) coefficient (γ33) of 86 pm/V at a wavelength of 1550 nm. A Mach-Zehnder interferometric polymer waveguide EO modulator had been designed and fabricated by using the PUI as a waveguide electro-optic core layer. The prepared polymer waveguide EO modulator showed a good electro-optic modulation response at a wavelength of 1550 nm under an applied 1 kHz sinusoidal modulation signal. The results showed that the synthesized PUI met the performance requirements for the preparation of polymer optical waveguide devices and was a polymer electro-optic waveguide material with good overall performance.

Effect of evaporation temperature on evaporative residue properties of waterborne polyurethane modified emulsified asphalt

Abstract In recent years, waterborne polyurethane (WPU) modified emulsified asphalt has attracted much attention. The conventional property of WPU-modified emulsified asphalt (WPU-MEA) is usually measured by using the evaporative residue obtained at high temperatures. In this work, WPU-MEA was prepared and the influence of evaporative temperature on the conventional performances (softening point, penetration, ductility) of the residue of WPU-MEA was investigated. Fourier Transform Infrared Spectroscopy (FTIR) and Fluorescence microscope (FM) were used to analyze the chemical structure and morphology of the evaporative residues. It was found that the evaporation dehydration temperature has a significant influence on the property of the evaporation residue of WPU-MEA. The evaporative residue performance of WPU modified asphalt was better at an evaporation temperature of 110°C, and the three conventional properties were significantly improved. Upon increasing the evaporation temperature, the conventional properties of WPU-MEA continue to decrease. As the evaporation temperature is 190°C, the conventional property of the residue is close to that of unmodified emulsified asphalt. Considering the performance index of WPU-MEA, the optimal evaporation temperature should be determined in the characterization of residue performance. This study has a guiding significance for the development of polyurethane-modified asphalt materials.

Polymeric artificial heart valves derived from modified diol-based polycarbonate polyurethanes

A series of polycarbonate silicone polyurethanes (SiPCUs) have been synthesized to develop elastomers with the mechanical properties, biostability, and biocompatibility required for artificial heart valve manufacturing. In these SiPCUs, the polar functional group 4,4′-dicyclohexylmethane diisocyanate (HMDI) was incorporated into the soft segment 1,6-poly (hexamethylene carbonate) diol (PCDL) to form the modified macromolecular diol, PCDL-HMDI-PCDL. The hard segment consisted of HMDI and the chain extenders 1,4-butanediol and 1,3-bis(4-hydroxybutyl)-1,1,3,3-tetramethyl disiloxane (BHTD). The synthesized PHC-PCUB improves the excessive microphase separation caused by the introduction of PDMS. This material possesses good physicochemical properties, long-term oxidative degradation stability, and comparatively low mechanical performance loss after degradation. Compared to the commercially available bioprosthetic heart valve (BHV) material Glut-PP, PHC-PCUB demonstrated enhanced biocompatibility, good thromboresistant properties, less calcification, and higher endothelial cell adhesion. Furthermore, valve prototypes fabricated with PHC-PCUB showed improved hemodynamic performance under various simulated conditions, highlighting the potential of PHC-PCUB as an advanced material for valve leaflets. Statement of SignificanceArtificial heart valves are crucial for treating valve diseases, and polyurethane-based valves present a promising alternative due to their durability, strong biocompatibility, and customizable properties. This study improves the biostability and post-degradation mechanical properties of siloxane polyurethanes by reducing the content of polydimethylsiloxane (PDMS) and adding modified diol (PCDL-HMDI-PCDL). By integrating hexamethylene diisocyanate (HMDI) and chain extenders, we developed polycarbonate siloxane polyurethanes (SiPCUs) that improve phase mixing, mechanical strength, and oxidative stability. These SiPCUs also exhibit good thromboresistance and calcification resistance, low cytotoxicity, and promote cell adhesion, positioning them as highly promising materials for heart valve leaflets, effectively addressing the limitations of current mechanical and bioprosthetic valves.

Analytical model of friction at low shear rates for soft materials in 3D printing.

The biological properties of silicone elastomers such as polydimethylsiloxane (PDMS) have widespread use in biomedicine for soft tissue implants, contact lenses, soft robots, and many other small medical devices, due to its exceptional biocompatibility. Additive manufacturing of soft materials still has significant challenges even with major advancements that have occurred in development of these technologies for customized medical devices and tissue engineering. The aim of this study was to develop a mathematical model of tangential stress in relation to shear stress, shear rate, 3D printing pressure and velocity, for non-Newtonian gels and fluids that are used as materials for 3D printing. This study used FENE (finitely extensible nonlinear elastic model) model, for non-Newtonian gels and fluids to define the dependences between tangential stress, velocity, and pressure, considering viscosity, shear stress and shear rates as governing factors in soft materials friction and adhesion. Experimental samples were fabricated as showcases, by SLA and FDM 3D printing technologies: elastic polymer samples with properties resembling elastic properties of PDMS and thermoplastic polyurethane (TPU) samples. Experimental 3D printing parameters were used in the developed analytical solution to analyse the relationships between governing influential factors (tangential stress, printing pressure, printing speed, shear rate and friction coefficient). Maple software was used for numerical modelling. Analytical model applied on a printed elastic polymer, at low shear rates, exhibited numerical values of tangential stress of 0.208-0.216 N m - 2 at printing velocities of 0.9 to 1.2 mm s - 1, while the coefficient of friction was as low as 0.09-0.16. These values were in accordance with experimental data in literature. Printing pressure did not significantly influence tangential stress, whereas it was slightly influenced by shear rate changes. Friction coefficient linearly increased with tangential stress. Simple analytical model of friction for elastic polymer in SLA 3D printing showed good correspondence with experimental literature data for low shear rates, thus indicating possibility to use it for prediction of printing parameters towards desired dimensional accuracy of printed objects. Further development of this analytical model should enable other shear rate regimes, as well as additional soft materials and printing parameters.

Synthesis and properties of reed-based polyurethane (PU) coating

Synthesis and properties of reed-based polyurethane (PU) coating

Mechanical Properties of Polyurethane Foam Reinforced with Natural Henequen Fibre

Polymeric foams are used in many applications, from packaging to structural applications. While polymeric foams have good mechanical performance in compression, they are brittle in tension and bending; fibre reinforcement can enhance their tension and flexural behaviour. This work reports a novel investigation of the mechanical properties of fibre-reinforced polyurethane (FRPU) foams with natural henequen fibres. Pull-out tests were performed with 10 mm fibres and various foam densities to identify the optimal density of 100 kg/m3. Thus, FRPU foams with this density and fibre contents of 1, 2 and 3 wt% were manufactured for mechanical testing. Compression tests showed an increase in the elastic modulus of the FRPU foam specimens compared to the unreinforced PU foam. The FRPU foams also exhibited higher yield stress, which was attributed to the reinforcing effect of the fibres on the cell walls. A maximum increase of 71% in the compressive yield stress was observed for the FRPU foam specimens with a fibre content of 2%. In addition, FRPU foam specimens absorbed more energy for any given strain than the unreinforced PU foam. Flexural tests showed the FRPU foams exhibited increased flexural strength compared to the unreinforced PU foam. A maximum increase of 40% in the flexural strength was observed for the FRPU foam with a fibre content of 1%. The findings reported here are significant because they suggest that FRPU foams incorporating natural henequen fibre exhibit promising potential as sustainable materials with enhanced mechanical properties.

Controllable Design and Synthesis of Polyurethane Elastomers Containing Polar Dangling Chains with High Mechanical Properties and Wide Damping Temperature Range.

Vibration and noise severely affect the operation of mechanical equipment and is also detrimental to human health. Therefore, the development of high performance damping materials is crucial. However, current methods to improve damping properties often come at the expense of mechanical properties, resulting in inferior mechanical performance of materials. In order to address the issue of imbalance between damping properties and mechanical properties in polyurethane damping elastomers. In this study, polyester dangling chains containing polar groups are synthesized and introduced into polyurethane. The obtained polyurethane exhibited an effective damping temperature range of 154 °C (-54 °C to 100 °C) and a tensile strength of 15.82 MPa. Furthermore, dynamic mechanical analysis and broadband dielectric relaxation spectroscopy are combined to investigate the influence of polar dangling chains on the structure and properties of polyurethane. The degree of microphase separation increases after the introduction of polar dangling chains, indicating enhances intermolecular interaction forces, facilitating the formation of hydrogen bond between the main chain and dangling chains, thereby increasing molecular chain friction and energy dissipation. This work overcomes the challenge of balancing the damping and mechanical properties of polyurethane, providing a new strategy for designing high performance polyurethane damping elastomers.