Poly Urethane-urea Research Articles

Facile synthesis of high-performance and self-healing polyurethane-urea nanocomposites reinforced with graphene

In this study, a facile method was employed to synthesize strong, yet highly elastic polyurethane-urea (PUU) with typical characteristics and 94 ​% optical transmittance. Graphene platelets (GNPs) were prepared and modified via a scalable and eco-friendly mechanochemical approach. The produced GNPs is at 1.6-nm thickness with high electrical conductivity of ∼950 ​S/m. The structure-property relations of PUU/GNP nanocomposites were comprehensively investigated through morphology and mechanical properties measurements. The strong interface and high-density hydrogen bonds between modified GNPs (M-GNPs) and PUU significantly enhanced the mechanical properties of the PUU nanocomposite. The PUU composite showed 66.7 ​% and 36.2 ​% increments in tensile and impact strengths, respectively, at 0.2 ​wt% M-GNPs. The reversible hydrogen bond between M-GNPs and PUU endowed the nanocomposite with self-healing properties achieving 97.8 ​% healing efficiency of the strength after 5 ​h at 120 ​°C. This study demonstrates the importance of surface modification and provides a simple yet robust approach for preparing high-performance and functional PUU/graphene composites.

Development of polyurethane urea（PUU）– Waste rubber particles (WRP) composite materials for active ice-breaking of groove-filled asphalt pavement

The grooved-filled asphalt pavement has certain advantages in terms of pavement ice-breaking and anti-skid. However, the performances of the filling material limit its development. In this study, a polyurethane urea (PUU) - waste rubber particles (WRP) composite filling material was prepared by using a polyurethane (PU) and adding polyurea (PUa) with a similar microstructure as the cementing material, and adding WRP as the elastic reinforcing phase. The proportions of nine PUU-WRP composite materials were designed by changing the particle size and content of WRP, and then the filled composite materials were evaluated in terms of physical and mechanical properties, ice adhesion properties, interface bonding properties and aging resistance. The test results showed that the shore hardness, tensile strength, compression permanent deformation, and contact angle of PUU-WRP composite decreased as content of the WRP increased. Except the ice adhesion force results were the opposite. On the other hand, increased the WRP size resulted in increase in PUU-WRP composite’s shore hardness, compression permanent deformation, and ice adhesion force, while the tensile strength and contact angle were the opposite. The surface of the PUU-WRP composite material was hydrophobic, and the maximum contact angle was 102.3°. The reduction of WRP particle size and dosage was beneficial for reducing the ice adhesion force on the surface of PUU-WRP composite materials. The maximum interfacial shear and tensile strength of PUU-WRP composite material were 1.082 MPa and 0.244 MPa, respectively. After 42 days of UV aging, the maximum attenuation rate did not exceed 30 %. After the immersion test, the tensile strength attenuation of PUU-WRP composite material was basically controlled within 10 %. Finally, based on the fuzzy comprehensive evaluation (FCE) method, it was recommended to use WRP with a particle size of 0.6 mm and a dosage of 30 wt%-40 wt%.

Thermoresponsive On-Demand Adhesion and Detachment of a Polyurethane-Urea Bioadhesive.

The development of bioadhesives with strong adhesion and on-demand adhesion-detachment behavior is still critically important and challenging for facilitating painless and damage-free removal in clinical applications. In this work, for the first time, we report the easy fabrication of novel polyurethane-urea (PUU)-based bioadhesives with thermoresponsive on-demand adhesion and detachment behavior. The PUU copolymer was synthesized by a simple copolymerization of low-molecular-weight, hydrophilic, and biocompatible poly(ethylene glycol), glyceryl monolaurate (GML, a special chain extender with a long side hydrophobic alkyl group), and isophorone diisocyanate (IPDI). Here, GML was expected to not only adjust the temperature-dependent adhesion behavior but also act as an internal plasticizer. By simple adjustment of the water content, the adhesion strength of the 15 wt % water-containing PUU film toward porcine skin is as high as 55 kPa with an adhesion energy of 128 J/m2 at 37 °C. The adhesion strength dramatically decreases to only 3 kPa at 10 °C, exhibiting switching efficiency as high as 0.95. Furthermore, the present PUU-based adhesive also shows good on-demand underwater adhesion and detachment with a cell viability close to 100%. We propose that biomaterial research fields, especially novel PUU/polyurethane (PU)-based functional materials and bioadhesives, could benefit from such a novel thermoresponsive copolymer with outstanding mechanical and functional performances and an easy synthesis and scaled-up process as described in this article.

Development and Characterization of Biodegradable Polyurethane-Urea-Based Hydrogels for the Prevention of Postoperative Peritoneal Adhesions.

Postoperative peritoneal adhesions occur after more than 60% of abdominal surgeries and can cause severe long-term side effects, such as chronic pain, infertility, and intestinal obstructions. However, currently available products for adhesion prophylaxis often lack efficiency or are too heavy to handle. Hydrogels are promising materials to be used for adhesion prevention as they show good mechanical stability and biocompatibility. Herein, we present a novel two-component sprayable, biodegradable, fast-curing, and shape-adaptive polyurethane urea (PUU) hydrogel system and the establishment of a full characterization approach to investigate its suitability for adhesion prophylaxis according to predefined chemical, mechanical, and biological criteria. We demonstrate that this PUU hydrogel system exhibits a fast-curing behavior, is resilient toward mechanical forces, is biocompatible, and reveals a degradation behavior within a desired time frame to reliably avoid the formation of adhesions. In addition, the PUU hydrogel system functions as an effective barrier for invading cells in vitro. Overall, we propose a guideline for the development and in vitro characterization of synthetic hydrogels for application in minimally invasive adhesion prophylaxis.

Electroactive additives into polyurethanes for high corrosion resistance coatings for mild steel

AbstractThere is a demand for innovative coatings such as polyurethane (PU) in industrial and commercial sectors to effectively combat corrosion on mild steel substrates. In this work, novel redox‐active polyurea (PUr) additives such as PUr‐diamine capped trimer (DCTA) and PUr‐diamine‐capped tetraaniline (DCTAni), derived from DCTA and DCTAni, were synthesized to enhance the anticorrosion properties of PU coatings. These are characterized using 1H nuclear magnetic resonance spectroscopy, Fourier transformed infrared, and high‐resolution mass spectrometry technical methods. These additives (2, 5, and 10 wt%) were dispersed in a polyurethane‐urea (PUU) matrix, which was synthesized from PTMG‐2000, and IPDI with dihydrazide adipate as a chain extender. The electroactivity of the coatings were evaluated using cyclic voltammetry (CV) and ultraviolet–visible spectroscopy. Furthermore, anticorrosion performance was assessed through electrochemical impedance spectroscopy and Tafel potentiodynamic polarization measurements. The optimal corrosion protection was achieved with increasing weight percent (wt%) of additive in PUU, showing a trend of 10% > 5% > 2%. Coatings reported maximum polarization resistance (Rp) of 122.15 MΩ, with corrosion rates (CR) as low as 2.38 × 10−6 mm/year. Accelerated salt spray testing over 600 h in a 5 wt% NaCl salt fog confirmed the coatings' durability. The microstructures of PUr particles were determined through FESEM characterization. Additive‐blended PUUs exhibited moderate tensile strength and elongation at break compared to the reference PUU matrix. The hydrophobicity of both the reference sample (PUU) and the additive‐blended coatings was measured, with the highest recorded value being at 93.1 ± 0.048 for 10 wt%. Thermal gravimetric analysis demonstrated polymer degradation with a maximum of T5% observed at 304.1°C.

Characterisation of Polyurethane-urea as Leading-Edge Erosion Resistant Materials of Wind Turbine Blades

Surrounded by oceans, building offshore wind turbines is a great strategy for archipelago countries, like Indonesia, to harvest renewable energy from wind. However, because of high rainfall rate, water droplet erosion on wind turbine blades is inevitably to be one of the most challenging problems. It causes decreasing produced energy and increasing cost of maintenance and repairment. A novel coating material which has better mechanical properties is therefore required. As a preliminary step, this work aims to characterise thermal and mechanical properties of soft and hard polyurethane-urea (PUU). In this work, the materials are soft PUU30 which has a hardness of 30 shore A, and hard PUU95 which has a hardness of 95 shore A. Thermal properties are characterised by Differential Scanning Calorimetry (DSC), while mechanical properties are investigated by tensile test at various strain rates. The results show that PUU95 has a higher strain rate dependence on modulus, tensile strength, and strain at break, which need to be considered for application regarding the range of wind speeds.

The effect of moisture on abrasive wear of urethane-containing elastomers

An increasing demand for the materials used in the mining industry necessitates extending the service life of polyurethane-type elastomers. This challenge can partially be met through optimal use of these elastomers, with their properties taken into account as dependent on moisture. The problem formulated like that implies the use of polyurethanes under conditions of a wide range of the relative air humidity values during different climatic seasons in different countries. This paper presents the results of a study in the changes in abrasive wear of urethane-containing elastomers (polyurethanes and polyurethane ureas) under moisture conditions. The purpose of the work being to study comparative resistance of different elastomers, chemically structured differently, to abrasive wear, the experiments were carried out as per the techniques standard for rubbers. An increase in stability of abrasive resistance of the elastomers under study, when moistened, was established to be ensured by a higher content of hard segments in polymer chains and stability of domain structures to the action of water. The effect produced by moisture on the properties of the elastomers under study is of nature of temporary plasticization. Generally, the oligoethers-based urethane-containing elastomers are more resistant to moisture than those based on oligoesters, but if the domain structure of an elastomer is unstable by reason of a steric hindrance, the pattern of the phenomenon can vary.

Highly stretchable, sensitive and healable epidermal electronics enabled by dynamic hard domains and multidimensional conductive fillers for human motion and biopotential sensing

Integration of self-healing ability and biomimetic structures into epidermal electronics is of great interest. Herein, mimicking the merits of human skin, dynamic hard domains and multidimensional conductive fillers were introduced into epidermal electronics. Firstly, aromatic disulfide bonds and H-bonds as dynamic hard domains from bis-(4-aminophenyl) disulfide and tetraethylene glycol were incorporated into polyurethane-urea (PU), and provided desired mechanical properties and self-healing capability. To enhance the strength and toughness, ZIF-67 nanoparticles with micro-pores and uncoordinated imidazole groups were introduced into PU matrix, producing excellent filler-matrix interfaces owing to the formation of high-density H-bonds and mechanical insertion. The optimized PU/ZIF-6710% composite exhibited high performance with a tensile strength of 4.15 MPa, an elongation at break of 1342.31 %, a toughness of 40.73 MJ m−3, a fracture energy of 157.75 kJ m−2, and healing efficiency of 93.25 %. Benefiting from the supramolecular PU with dynamic hard domains and multidimensional conductive fillers, the as-prepared multifunctional films exhibited excellent self-healing ability and sensing performance with a wide detection range (609 %), high sensitivity (3416.71), fast response time (65 ms), low detection limit (0.026 %), and excellent robustness (∼1000 cycles at 50 % strain). Different human motions and high-quality electrophysiological signals were successfully detected by the original and healable epidermal electrodes.

Preparation and properties of silica fume@polyure-thane urea cement composites

In this study, a new material was synthesized by compounding silica fume and polyurethane urea, which is used to evaculate the vibration reduction performance of concrete. The mechanical and damping properties of silica fume@ polyurethane urea (SF@PUU) reinforced cement paste were investigated. Also, FT-IR, XRD, TG analysis, and SEM are included. The results indicated that SF@PUU leads to the production of high damping ratio cement pastes. The damping capacities of SF@PUU cement composites, where the damping mechanism included internal, external, and multiphase friction within the cement matrix. Additionally, SF@PUU created a constrained-layer damping structure in cement paste to improve the damping properties. The review confirmed that SF@PUU subjected to proper treatments can be as the replacement to cement in concrete or as a damping filler. However, more investigation is required into the dimensional stability and durability of SF@PUU-based concrete.

Shape-recovery of implanted shape-memory devices remotely triggered via image-guided ultrasound heating

Shape-memory materials hold great potential to impart medical devices with functionalities useful during implantation, locomotion, drug delivery, and removal. However, their clinical translation is limited by a lack of non-invasive and precise methods to trigger and control the shape recovery, especially for devices implanted in deep tissues. In this study, the application of image-guided high-intensity focused ultrasound (HIFU) heating is tested. Magnetic resonance-guided HIFU triggered shape-recovery of a device made of polyurethane urea while monitoring its temperature by magnetic resonance thermometry. Deformation of the polyurethane urea in a live canine bladder (5 cm deep) is achieved with 8 seconds of ultrasound-guided HIFU with millimeter resolution energy focus. Tissue sections show no hyperthermic tissue injury. A conceptual application in ureteral stent shape-recovery reduces removal resistance. In conclusion, image-guided HIFU demonstrates deep energy penetration, safety and speed.

Synthesis and research of polyurethane urea with 2-(2-aminoethoxy)ethan-1-amine and 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propane-1-amine as macrochain extenders, and compositions with ifosphamide based on them

Polyurethane urea (PUU) was synthesized using macrochain extenders of 2-(2-aminoethoxy)ethan-1-amine (DA1) and 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propan-1-amine (DA3) at a molar ratio of 4,4'-diaminodiphenylmethane (DADP) to DA1 and DA3 as 30:70; 50:50; and 70:30. The tensile strength () of PUU is in the range of 0.74–2.21 MPa, and the relative elongation at break () is 27.4–1003%. According to the DSC method, the studied PUUs are single-phase systems. The glass transition temperature (Tg) of the PUU DA1 series is from 21.920C to –39.480C, and the glass transition temperature for the PUU DA3 is from –20.040C to –33.960C. Based on the synthesized PUUs, composite materials were prepared containing 1 wt.% of ifosfamide (IFO) (=0.74–2.21 MPa, and =31.8–276.3%). According to the results of thermophysical studies, the compositions with IFO are single-phase systems with Tg of –24.80C to –36.220C. Thus, the introduction of IFO into the composition leads to an increase in the packing density of the macrochain, a decrease in the size of the free volume and, consequently, a decrease in the mobility of the blocks in space and a decrease in Сp. Compositions with IFO are resistant to temperatures of ~2500C, which allows thermal sterilization before use. Using the HPLC-UV method, the dynamics of IFO release from samples of PUU compositions synthesized at a molar ratio of DADP:DA1 as 0.5:0.5 and DADP:DA3 as 0.7:0.3 was investigated. It was established that IFO is released within 60 days from compositions based on PUU DA3 in the amount of 29.6%, and from compositions based on PUU DA1 in the amount of 42% with respect to the total amount of IFO introduced. The resulting composites are promising materials for medicine as means of local prolonged therapeutic action.

Study on the Properties of Polyurethane–Urea Elastomers Prepared by TDI/MDI Mixture

Study on the Properties of Polyurethane–Urea Elastomers Prepared by TDI/MDI Mixture

FILM-FORMING COMPOSITIONS BASED ON POLYURETHANEUREAS WITH EXTENDED RELEASE OF DACARBAZINE

Composite materials with dacarbazine (DK) containing 1 wt. % were obtained on the basis of polyurethane ureas (PUU) containing in the structure as extenders of the macrochain of 2-(2-aminoethoxy)ethan-1-amine, (DA1) 3,6-dioxaoctane-1,8-diamine (DA2) 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propan-1-amine (DA3) with a molar ratio of 4,4’-diaminodiphenylmethane (DADPh) to DA1 and DA3 as 30:70; 50:50; 70:30. The tensile strength of the compositions is within (1.21-1.27) MPa, the relative elongation is (303.9-384)%. Studies of thermophysical properties of synthesized PUU by DSC, TGA methods were conducted. Dacarbazine compositions are single-phase systems with glass transition temperature (Tg) from -33.55°C to -37.06°C. It was established that the introduction of Dacarbazine into the composition of PUU leads to a decrease in Tg and ΔCp during the second warm-up in comparison with the original PUU. Dacarbazine compositions are resistant to temperatures of 270oC, which allows for thermal sterilization before use. The release of Dacarbazine from polymer samples into the solution was studied by the spectrophotometric method. According to the results of the study of the dynamics release of Dacarbazine, it was es tablished that for (PUU DA1)2+DK in 14 days it is 61.74%, (PUU DA2)4+DK - 70.09%, (PUU DA3)2+DK - 56.75% of the total amount of immobilized DK. The resulting composites are perspective materials for medicine as means of local prolonged therapeutic action.

Synthesis of poly(propylene fumarate)-polyurethane urea composite with kartogenin-modified chitosan for cartilage tissue engineering

In this research, we explored the development of a cross-linked polymer composite, poly(propylene fumarate)-polyurethane urea (PPFUU), designed to foster the differentiation of human adipose-derived mesenchymal stem cells (hADMSCs) into chondrocytes. PPFUU was synthesized using PPF-diol, 1,6-diisocyanatohexane, and putrescin, which served as the soft section, hard section, and chain extender, respectively. To optimize its characteristics, PPFUU was integrated with a chitosan-kartogenin conjugate (CS-KGN) at varying weight fractions. The blend underwent chemical crosslinking via free radical polymerization, with benzoyl peroxide as the initiator and N-vinyl pyrrolidinone as the crosslinking agent. The resulting composites were rigorously analyzed for different properties, including thermal behavior, hydrophilicity, compressive strength, biocompatibility, and more. Significantly, the introduction of CS enhanced glycosaminoglycan formation. Furthermore, hADMSCs, when cultured in chondrogenic media on the CS-KGN-integrated PPFUU composite, exhibited upregulated SOX9 and aggrecan expression. Based on these in vitro results, the CS-KGN-conjugated PPFUU composite presents a promising avenue for cartilage tissue regeneration.

Preparation of Polyurethane–Urea Fibers with Controlled Surface Morphology via Gel State

It is widely known that skin irritation can be induced by interactions between polymer fibers constituting clothing and the skin, leading to skin inflammation and unfavorable dermatological reactions. Thus, significant endeavors have been directed toward ameliorating this phenomenon. This study engineered synthetic fibers with reduced potential for skin irritation. This was achieved via a strategy inspired by the inherent smoothness of silk fibers, which exhibit minimal friction and irritation against the skin. This investigation focused on urethane fibers, a class of synthetic fibers frequently used in textile applications. Hydrogel cross-linked polyurethane–urea fibers were subjected to controlled swelling in different hydrophilic mixed-solvent environments. Subsequent freeze-drying procedures were employed to yield fibers with diverse surface morphologies and encompassing features such as elevations and creases. The correlation between the compositions of the solvent mixtures used and the resulting surface morphologies of the fibers was rigorously assessed through polarized light and scanning electron microscopies. Additionally, the interplay between the degree of swelling and the tensile strength of the fabricated fibers was comprehensively analyzed. Consequently, the methodological combination of swelling and freeze-drying endowed the polyurethane–urea fibers with various surface profiles. Future studies will delve into the intricate connection between fiber surface characteristics and their potential to induce skin irritation. It is envisaged that such investigations will substantially contribute to the refinement of textile fibers designed for enhanced compatibility with the skin.

Bioinks Functionalized with Natural Extracts for 3D Printing

In the search of materials valid for direct ink writing (DIW) 3D printing and with special interest for the biomedical and pharmaceutical applications, the development of bioactive inks for DIW is of great interest. For that purpose, in this work bioactive waterborne polyurethane–urea inks were prepared by addition of natural extracts (logwood, chestnut, and alder buckthorn) and cellulose nanofibers (CNF). The rheological behavior of the inks proved to be strongly dependent on the extract type and content, and the addition route used. Inks prepared by ex-situ incorporation of the extracts showed a strong gel-like behavior, as did inks prepared with chestnut and alder buckthorn extracts, which, in turn, hindered a continuous flow during the printing process, resulting in 3D printed parts with poor shape fidelity. On the other hand, inks prepared in-situ and with logwood extract showed more facility to flow and higher homogeneity, which translated in better printability and better shape fidelity, further enhanced for CNF containing inks. 3D printed composites showed reinforced mechanical behavior, as well as in materials with enhanced antibacterial behavior. Overall, the possibility to successfully prepare bioactive inks valid for 3D printing was proven.

Synthesis, Characterization, and Processing of Highly Bioadhesive Polyurethane Urea as a Microfibrous Scaffold Inspired by Mussels

Synthesis, Characterization, and Processing of Highly Bioadhesive Polyurethane Urea as a Microfibrous Scaffold Inspired by Mussels

Influence of Relative Air Humidity on the Abrasion Resistance of Polyurethane Ureas with Different Hard Segment Content in a Polymer Chain

Influence of Relative Air Humidity on the Abrasion Resistance of Polyurethane Ureas with Different Hard Segment Content in a Polymer Chain

A stretchable, mechanically robust polymer exhibiting shape-memory-assisted self-healing and clustering-triggered emission

Self-healing and recyclable polymer materials are being developed through extensive investigations on noncovalent bond interactions. However, they typically exhibit inferior mechanical properties. Therefore, the present study is aimed at synthesizing a polyurethane–urea elastomer with excellent mechanical properties and shape-memory-assisted self-healing behavior. In particular, the introduction of coordination and hydrogen bonds into elastomer leads to the optimal elastomer exhibiting good mechanical properties (strength, 76.37 MPa; elongation at break, 839.10%; toughness, 308.63 MJ m−3) owing to the phased energy dissipation mechanism involving various supramolecular interactions. The elastomer also demonstrates shape-memory properties, whereby the shape recovery force that brings damaged surfaces closer and facilitates self-healing. Surprisingly, all specimens exhibite clustering-triggered emission, with cyan fluorescence is observed under ultraviolet light. The strategy reported herein for developing multifunctional materials with good mechanical properties can be leveraged to yield stimulus-responsive polymers and smart seals.

A polyurethane-urea elastomer at low to extreme strain rates

A finite strain nonlinear constitutive model is presented to study the extreme mechanical behavior of a polyurethane-urea (PUU) well suited for many engineering applications. The micromechanically- and thermodynamically based constitutive model captures salient features in resilience and dissipation in the material from low to extreme strain rates. The extreme deformation features are further elucidated by laser-induced micro-particle impact tests for the material, where an ultrafast strain rate (>106 s−1) incurs. Numerical simulations for the strongly inhomogeneous deformation events are in good agreement with the experimental data, supporting the predictive capabilities of the constitutive model for the extreme deformation features of the PUU material over at least 9 orders of magnitude in strain rates (10−3 to 106 s−1).