Poly Urethane-urea Research Articles

Development of an electrochemical membrane bioreactor for succinic acid production and in situ separation with engineered Yarrowia lipolytica cultivated on municipal biowaste hydrolysate

A novel electrochemical membrane bioreactor (EMB) integrating succinic acid (SA) production and in situ separation in the anode compartment through an anion exchange membrane was employed in fed-batch fermentations with Y. lipolytica PSA02004 using hydrolysates from the organic fraction of municipal solid waste (OFMSW) as feedstock. The initiation of electrolysis cell operation and the reduction of pH from 6 to 5.5 at 30 h in a 6.7 L bioreactor improved the SA production efficiency, resulting in 66.7 gSA/L, 0.51 g/g yield, 0.78 g/(L·h) productivity, high coulombic efficiency (66.2%) and relatively low electricity consumption for SA separation (2.6 kWh/kgSA). The recirculation of the fermentation broth in the cathode compartment and the OH– produced by water reduction reduced NaOH consumption (35.4%) for pH control during fermentation. The fermentation was efficiently replicated in a 30 L bioreactor with a low membrane surface area (100 cm2) electrolysis cell, but it failed with a higher membrane surface area (702 cm2) electrolysis cell indicating that yeast cell viability, cell design and EMB configuration are important aspects for process scale-up. SA crystals were purified, at 99.95% purity and 95% yield, from the anolyte solution via activated carbon treatment, evaporation, crystallization and drying. Cell removal via centrifugation and acidification stages were not required as in conventional SA purification processes. The produced SA crystals were suitable for the production of polyester polyols for polyurethane urea dispersions applications.

Robust, self-healing, anti-corrosive waterborne polyurethane urea composite coatings enabled by dynamic hindered urea bonds

To meet the increasing concerns for health, safety, and the environment, traditional solvent coatings are gradually replaced by their waterborne counterparts and the development of robust and self-healing waterborne polymers is showing important application significance. Herein, waterborne polyurethane urea composite coatings (WPUU) with dynamic hindered urea bonds are reported. The dispersion of WPUU synthesized with hindered amine as the chain extender has a smaller particle size. The mussel-inspired polydopamine modification was applied to improve the dispersion and interfacial interactions of carbon nanotubes (CNTs) in the WPUU matrix. Due to the dynamic reversibility of the hindered urea and abundant hydrogen bonding, the resulting WPUU-2T2B can achieve self-healing at 70 °C, also showing good mechanical toughness, the tensile strength of 34.0 MPa and elongation at break of 530 %. After adding the modified CNTs, 10%PDA@CNTs/WPUU demonstrates the tensile strength of 22.4 MPa, elongation at break of 251 % and yield strength of 13.1 M Pa. The self-healing properties of nanocomposites are still retained. The maximum electrical conductivity of the composite coating reaches 56.8 S m−1. The composite coating can recover excellent corrosion resistance in the electrolyte environment after healing, which could ensure its safety and sustainability in the long-term service. We envisage this work offers an idea for the fabrication of environmentally friendly, self-healing, corrosion resistant and electrically conductive coatings with good thermal stability and robust mechanical properties.

Force-Induced Shuttling of Rotaxanes Controls Fluorescence Resonance Energy Transfer in Polymer Hydrogels

The molecular shuttling function of rotaxanes can be exploited to design mechanoresponsive reporter molecules. Here, we report a new approach to such rotaxane-based mechanophores, in which the fluorescence resonance energy transfer (FRET) between a donor-acceptor pair is mechanically controlled. A cyclic molecule containing a green-light-emitting FRET donor connected to a red-light-emitting FRET acceptor was threaded onto an axle equipped with a quencher at its center and two stoppers in the peripheral positions. In the force-free state, the green emitter is located near the quencher so that charge transfer interactions or photo-induced electron transfer between the two moieties suppress green emission and prevent the FRET from the green to the red emitter. The mechanophore was covalently incorporated into a linear polyurethane-urea (PUU), and stretchable hydrogels were prepared by swelling this polymer with water. Upon deformation of the PUU hydrogels and under an excitation light that selectively excites the donor, the intensity of the red fluorescence increases, as a result of a force-induced separation of the green emitter from the quencher, which enables the FRET. The switching contrast is much more pronounced in the gels than in dry films, which is due to increased molecular mobility and hydrophobic effects in the hydrogel, which both promote the formation of inclusion complexes between the ring containing the green emitter and the quencher.

Fast-Tracking of the Segmental Orientation in Poly(ethylene oxide)-based Polyurethane Urea by Mechano-optical (Infrared Dichroism and Birefringence) Properties: Degree of the Soft-Segment Ordering Effect

The orientation behavior of segment-specific chemical groups of NH and CH was investigated for poly(ethylene oxide) (PEO)-based polyurethane urea (PUU) during uniaxial stretching using a uniaxial stretching system integrated with spectral birefringence and ultrafast IR spectrometers that capture two polarization states simultaneously. PUUs with 30% by-weight urethane-urea hard segment content were prepared using PEO oligomers with number average molecular weights of 2000, 4600, and 8000 g/mol. High-molecular weight PEO-based PUUs exhibited microphase morphologies with sharp interfaces between the PEO matrix and urethane-urea hard segments, while low-molecular weight PEO-2000 (2000 g/mol)-based PUU exhibited a gradient interphase. This is primarily due to substantial hydrogen-bonding interactions between the urea hard segments and ether groups of highly amorphous PEO-2000 compared with highly crystalline soft segments in PEO-4600 and PEO-8000, which lack significant hydrogen-bonding interactions with urea groups and hence a sharper interface and improved microphase separation. The segment-specific chemical group orientation study revealed that the relaxation and reorganization behaviors are closely dependent on the initial morphology. In microphase-separated PUU with a gradient interphase, responses of the hard and soft segments to deformation are similar even at lower strain levels. For the microphase-separated PUUs with a sharp interface, the low-strain level orientation is localized in the soft-segment regions until the connection with the hard segments drive the orientation in the chain axis toward the stretching direction. This network transition is also reflected in the mechano-optical behavior as a change from a high-strain optical constant to a lower-strain optical constant.

Влияние относительной влажности воздуха на износостойкость полиуретанмочевин с разным содержанием жестких сегментов в полимерной цепи

It was determined that wetting polyurethane urea based on polytetramethylene oxide diol Polyfurit-1000 lead to significant deterioration in their resistance to the abrasive wear. This effect was associated with a weakening of the interchain interaction in the studied polymers relating with the moisture action. The results were compared with suitable changes in the elastic and strength characteristics of the studied materials.

Autonomous self-healing optical sensors for damage intelligent soft-bodied systems.

We introduce damage intelligent soft-bodied systems via a network of self-healing light guides for dynamic sensing (SHeaLDS). Exploiting the intrinsic damage resilience of light propagation in an optical waveguide, in combination with a tough, transparent, and autonomously self-healing polyurethane urea elastomer, SHeaLDS enables damage resilient and intelligent robots by self-healing cuts as well as detecting this damage and controlling the robot's actions accordingly. With optimized material and structural design for hyperelastic deformation of the robot and autonomous self-healing capacity, SHeaLDS provides reliable dynamic sensing at large strains (ε=140%) with no drift or hysteresis, is resistant to punctures, and self-heals from cuts at room temperature with no external intervention. As a demonstration of utility, a soft quadruped protected by SHeaLDS detects and self-heals from extreme damage (e.g., six cuts on one leg) in 1 min and monitors and adapts its gait based on the damage condition autonomously through feedback control.

Bioabsorbable, elastomer-coated magnesium alloy coils for treating saccular cerebrovascular aneurysms

Cerebral aneurysm embolization is a therapeutic approach to prevent rupture and resultant clinical sequelae. Current, non-biodegradable metallic coils (platinum or tungsten) are the first-line choice to secure cerebral aneurysms. However, clinical studies report that up to 17% of aneurysms recur within 1 year after coiling, leading to retreatment and additional surgery. It would be ideal for the aneurysm coiling material to induce acute thrombotic occlusion, contribute to a tissue development process to fortify the degenerated vessel wall, and ultimately resorb to avoid leaving a permanent foreign body. With these properties in mind, a new fatty amide-based polyurethane urea (PHEUU) elastomer was synthesized and coated on biodegradable metallic (Mg alloy) coils to prepare a bioabsorbable cerebral saccular aneurysm embolization device. The chemical structure of PHEUU was confirmed using two-dimensional nuclear magnetic resonance spectroscopy. PHEUU showed comparable physical properties to elastomeric biodegradable polyurethanes lacking fatty amide immobilization, modest enzymatic degradation profiles in the first 8 wks, inherent antioxidant activity (>70% at 48 h), no cytotoxicity, and better protection for the underlying Mg alloy than poly(lactic-co-glycolic acid) (PLGA) against surface corrosion and cracking. Rat aortic smooth muscle cell attachment and platelet deposition were higher with the PHEUUs compared to bare or PLGA coated Mg alloy in vitro. PHEUU-coated Mg alloy coils showed the potential to design a fully bioabsorbable embolization coil amenable to clinical placement conditions based on computational mechanics modeling and blood-contacting test using an in vitro aneurysm model. In vivo studies using a mouse aneurysm model elicited comparable inflammatory cytokine expression to a commercially available platinum coil.

Domain Structure, Thermal and Mechanical Properties of Polycaprolactone-Based Multiblock Polyurethane-Ureas under Control of Hard and Soft Segment Lengths.

A series of multiblock polyurethane-ureas (PUU) based on polycaprolactone diol (PCL) with a molecular mass of 530 or 2000 g/mol, as well as hard segments of different lengths and structures, were synthesized by the step-growth polymerization method. The chemical structure of the synthesized multiblock copolymers was confirmed by IR- and NMR-spectroscopy. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to determine the relaxation and phase transition temperatures for the entire series of the obtained PUU. The X-ray diffraction (XRD) method made it possible to identify PUU compositions in which the crystallizability of soft segments (SS) is manifested due to their sufficient length for self-organization and structuring. Visualization of the crystal structure and disordering of the stacking of SS with an increase in their molecular mobility during heating are shown using optical microscopy. The change in the size of the hard phase domains and the value of the interdomain distance depending on the PCL molecular mass, as well as the length and structure of the hard block in the synthesized PUU, were analyzed using small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS). The evolution of the domain structure upon passing through the melting and crystallization temperatures of PUU soft blocks was studied using SANS. The studies carried out made it possible to reveal the main correlations between the chemical structure of the synthesized PUU and their supramolecular organization as well as thermal and mechanical properties.

Treatment of Insertional Achilles Tendinosis With Polyurethane Urea-Based Matrix Augmentation.

Surgical treatment for insertional Achilles tendinosis (IAT) sometimes requires tendon repair augmentation. The purpose of this study is to evaluate the efficacy of polycaprolactone-based polyurethane urea (PUUR) matrix augmentation in the treatment of IAT. A retrospective review was performed in surgically treated IAT. Repairs were augmented with a PUUR matrix. Factors evaluated included date of full weightbearing, patient satisfaction, Visual Analog Scale (VAS) pain score, strength, and ankle motion. The Wilcoxon signed-rank test was used to compare baseline and final follow-up VAS scores. A total of 18 cases were included in the study. The mean patient age was 54.61 ± 8.25 (40-75) years with a mean follow-up of 163.61 ± 57.81 (92-314) days. Patient satisfaction was obtained on 15 of 18 patients, with 14 patients satisfied with their outcome. Mean VAS for pain significantly decreased from 6.19 ± 1.97 (2.5-9) to 0.83 ± 1.54 (0-5) postoperatively, which was statistically significant (P < .01). Achilles tendon augmentation with the PUUR matrix is a viable option in the treatment of IAT. Its use in this condition has minimal morbidity and can be an alternative to other forms of augmentation. Level IV: Retrospective case series.

Poly(L‐lactic acid) and poly(ε‐caprolactone) based ultra‐strong and tough thermoplastic polyurethane‐urea with multi‐urea segments and oriented microstructures

AbstractAlthough poly(L‐lactic acid) (PLA) has been widely studied and used in biomedical areas because of its well‐known biocompatibility, degradability and renewability, its potential application is still greatly limited by its brittleness and poor ductility. In this work, we, for the first time, reported a series of multi‐urea linkage segmented ultra‐strong thermoplastic polyurethane‐urea (PUU) copolymers using PLA and poly(ε‐caprolactone) as the mixed soft segments and water as an indirect in situ chain extender. The tensile strength, elongation at break and tensile modulus of the obtained PUU copolymers are 45–52 MPa, 380–540% and 180–430 MPa, respectively. After a simple one‐step uniaxial tensile deformation was applied to these PUU copolymers, their tensile strength and tensile modulus could be dramatically increased to 200 and 630 MPa, respectively, while maintaining enough good ductility (elongation at break &gt;50%). Scanning electron microscope and Wide‐angle X‐ray Diffraction results showed that the dramatically improved mechanical performance should be mainly attributed to their more oriented microstructures. This study provided an easy strategy to pursuing synthetic PLA based biopolymers combining with ultrahigh mechanical strength and biocompatible and degradable properties.

SYNTHESIS AND RESEARCH OF THE NEW POLYURETHANE UREAS THAT CONTAINE 1,8-DIAMINO-3,6-DIOXAOCTANE AS EXTENDER OF MACROCHAINE

A number of polyurethane ureas (PUUs) containing 1,8-diamino-3,6-dioxooctane (DOODA) in their structure as a macrochain extender were synthesized with a different molar ratio of 4,4'-diaminodiphenylmethane (DADPh) to DOODA as 30:70; 50:50; 70:30. Synthesized polymers are elastic, transparent films with a thickness of 0.3 mm. According to the results of physical and mechanical tests, the tensile strength of the synthesized PUUs is in the range of (0.7-2.0) MPa, and the relative elongation at break is in the range of (73.9-584.7)%. The best physical and mechanical characteristics have the polymer synthesized with a ratio of DADPh:DOODA as 0.3:0.7 with a tensile strength of 2.0 MPa and a relative elongation of 522%. The formation of PUUs was confirmed by the method of IR-spectroscopy. Thermophysical properties synthesized by DSC, TGA methods were studied. It was established that the glass transition temperature (Tg) in a number of synthesized PUUs with DOODA is in the range from (minus) 18.50 °C to (minus) 34.52 °C. An increase in the content of 1,8-Diamino-3,6-dioxaoctane in the PUUs structure leads to a decrease in Tg and a slight increase in ΔCp during the second heating. According to the TGA, the heat resistance characteristics of the synthesized PUUs depend on the content of DOODA. When entering the structure of the PUUs DOODA, a decrease of the temperature of the start of the decomposition (T0) and the temperature of the maximal speed of the decomposition (Tmax), which is non-linear nature. T0 of the synthesized PUUs is in the range (275.16-289.8)°C and is accompanied by a slight loss of mass (0.007-0.093)%. Synthesized PUUs are heat-resistant to a temperature of 275.16 °C, which makes it possible to carry out dry sterilization of samples without changing their characteristics. Synthesized PUUs are promising materials for the immobilization of medicinal substances for further use in medicine.

The properties of novel hydroxyl contained polyurethaneurea prepared from CO2 derived chain extenders

A series of novel amino-alcohol compounds were synthesized from ethylenediamine and cyclic carbonates derived from different glycidyl ethers and CO2. The amino-alcohols were applied as chain extender for the preparation of polyurethaneurea (PUU) containing hydroxyl groups. The influence of the amino-alcohols on the structure and property of PUU were studied by mechanical testing, Fourier transform infrared spectroscopy (FT-IR), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetry (TG) et. al. The tensile strength of hydroxyl contained polyurethaneurea CDMEDA-PUU could reach 28.27 MPa, about 260% higher than the hydroxyl shielded one. The results proved that the introduced hydroxyl groups greatly enhanced the hydrogen bonding within PUU and the structure of amino-alcohol had certain impact on PUU performance. The cyclic tensile test results further disclosed the existence of strong hydrogen bonding among the hard segments and the long-range connectivity of the permeable hard domains.

Preparation and Evaluation Mechanic Damping Properties of Fused Silica Powder@Polyurethane Urea/Cement Composites.

In this paper, cement based on fused silica powder @ polyurethane urea (FSP@PUU) with a micro constrained damping structure was studied. Firstly, FSP@PUU core-shell particles were prepared by heterogeneous stepwise addition polymerization method and added into cement paste as damping filler to form a micro-constrained damping structure inside cement paste. The mechanical property and damping performance of cement-based composites were characterized by compressive strength, dynamic mechanical analysis (DMA) test and modal vibration test. The results showed that the damping performance of FSP @ PUU cement-based composites was affected by temperature, and the loss tangent of cement with 6wt% FSP@PUU increased to about 0.057 at −35 °C to 35 °C, which was 1.5 times cement paste within the glass transition temperature. With 6 wt% FSP@PUU, the damping ratio of cement-based composites increased by 58% compared with cement paste in the frequency range of 175–300 Hz, while the compressive strength decreased by only 5%. The cement with suitable FSP@PUU possesses excellent damping performance.

Artelon as a Bio-Scaffold to Augment Collateral Ligament Repair after Knee Dislocation.

Introduction:Knee dislocations (KD) have high rates of multi-ligamentous injury (MLI). Collateral ligaments rupture in 50-60% of KDs. Traditionally, collateral ligaments have undergone primary repair, though microscopic healing is not optimal. Artelon is a degradable, polyurethane urea bio-scaffold thought to decrease mechanical forces and promote healing, motion, and strength. Currently, little evidence exists regarding its indications or outcomes.Material and methods:Thirty-two patients with KD and MLI undergoing collateral ligament repair at a level-I trauma centre between 2015-2020 were included. Patients age <18, with ipsilateral fractures or inadequate follow-up were excluded. The Artelon (AG) and primary ligamentous repair group (PR) each included 16 patients. Injury and perioperative variables were evaluated using SPSS® .Results:Thirty-two KDs were included in 32 patients, with 60% anterior. There were no significant differences between the two cohorts demographically or with regards to the type or severity of injury sustained. Meniscal pathology was addressed in 14 patients in both groups. Thirty-eight percent of all patients lacked >15° of knee flexion. Only one gross failure occurred, in the AG. No differences were noted in infection or re-operation. Lysholm Knee Scale and Tegner Activity Scale were not significantly different, although Tegner scores in both cohorts decreased from pre-injury scores.Conclusions:In summary, Artelon appears to be safe without increasing risk for hypersensitivity or infection when used for collateral ligament augmentation. Additionally, Artelon appeared to be non-inferior and statistically equivalent to primary repair in this setting and may have promise with use in certain types of knee dislocations.

Novel Molecular-Level Insight into the Self-Healing Behavior and Mechanism of Polyurethane-Urea Elastomer Based on a Noncovalent Strategy

A larger number of studies successfully prepared various polymer materials with excellent self-healing properties, but the study on the underlying self-healing mechanism remains comparably backward and still unclear. In this study, we prepared a self-healing polyurethane-urea (PUU) elastomer based on noncovalent bonds. Then, a coarse-grained model of PUU was successfully constructed using the iteration Boltzmann inversion (IBI) method. Microphase separation and mechanical properties of PUU were reproduced using this model by coarse-grained molecular dynamics (MD) simulation. The three-stage healing mechanism comprised the following: (1) movement of the material to close the gap, (2) interdiffusion of the polymer, and (3) bond exchange. The mechanism was revealed by determining the effects of hard segment content on the microstructure (chain entanglement, interactions of soft and hard segments, chain motility) and healing capacity over healing time. In the initial stage of healing, the polymer chains were disentangled, and the degree of entanglement of the healed samples decreased. A novel experimental strategy confirmed the transition of hydrogen bonds from disorder to order during the healing process. The motility of the cut polymer chains (low molecular weight), especially the cut soft segment, and the disordered hydrogen bonds played a key role in the healing capacity. The increased content of the ordered hydrogen bonds led to the formation of a hard segment network, which was not conducive to healing. Finally, the promoting mechanism of external factors, such as heating and trace amount of solvent, on the healing of PUU was explained. Our work systematically and profoundly reveals the self-healing behavior and mechanism of microphase-separated PUU at the molecular level.

Effects of Ligands in Rare Earth Complex on Properties, Functions, and Intelligent Behaviors of Polyurea-Urethane Composites.

There is a need to create next-generation polymer composites having high property, unique function, and intelligent behaviors, such as shape memory effect (SME) and self-healing (SH) capability. Rare earth complexes can provide luminescence for polymers, and their dispersion is highly affected by ligand structures. Here, we created three different REOCs with different ligands before studying the effects of ligands on REOC dispersion in polyurea–urethane (PUU) with disulfide bonds in main chains. In addition, the effects of different REOCs on mechanical properties, luminescent functions, and intelligent behaviors of PUU composites were studied. The results showed that REOC I (Sm(TTA)3phen: TTA, thenoyltrifluoroacetone; phen, 1,10-phenanthroline) has incompatible ligands with the PUU matrix. REOC I and REOC III (Sm(BUBA)3phen: BUBA, 4-benzylurea-benzoic acid) with amine and urea groups facilitate their dispersion. It was REOC III that helped the maintenance of mechanical properties of PUU composites due to the good dispersion and the needle-like morphologies. Due to more organic ligands of REOC III, the fluorescence intensity of composite materials is reduced. The shape recovery ratio of the composite was not as good as that of pure PUU when a large amount of fillers was added. Besides, REOC I reduced the self-healing efficiency of PUU composites due to poor dispersion, and the other two REOCs increased the self-healing efficiency. The results showed that ligands in REOCs are important for their dispersion in the PUU matrix. The poor dispersion of REOC I is unbeneficial for mechanical properties and intelligent behavior. The high miscibility of REOC II (Sm(PABA)3phen: PABA, 4-aminobenzoic acid) decreases mechanical properties as well but ensures the good shape recovery ratio and self-healing efficiency. The mediate miscibility and needle-like morphology of REOC III are good for mechanical properties. The shape recovery ratio, however, was decreased.

STUDYING OF THE NANOSTRUCTURIZED POLY(URETHANE-UREA) – POLY(VINYL CHLORIDE) BLEND MODIFIED BY AEROSILS

An influence of surface adsorption-active centers of fine amorphous silica on physical hydrogen bonding (H-bonding) network in polyurethaneurea (PUU) and nanostructurized polymer blend (PUU/30PVC) was studied by FTIR spectroscopy. PUU was synthesized by prepolymer approach in N,N-dimethylformamide (DMF) solution using poly(propylene glycol) of Mn = 1000, 2,4-tolylene diisocyanate and 2,4-tolylene diamin as a chain extender at a molar ratio of 1:2:1. The compositions were obtained by solution-casting technique using DMF as a solvent. It was found introducing fine silica with hydroxylated surface into PUU matrix enhances segregation of hard urethane-urea segments in oligoether matrix. The maximum of strengthening of the filled composites was observed when silica A-300 content reaches 2–3 % (by weight). Oppositely, introducing silica AM-300 with silylated (by (CH3)2SiCl2) surface into PUU initiates degrading domain structure of elastomer due to interactions between polar groups of chemisorbed molecules of chlorine-containing modifier and proton-donor groups of rigid segments. Modified surface of silica has minor destabilization effect on H-bonding network in nanostructurized polymer-polymer blend. As a result, for producing filled composites without weakening interface interactions and, respectively, reducing the strength and optimal filler content (silica AM-300 or A-300) should be selected as high as 1 % (by weight).

Development of stimulus-sensitive electrospun membranes based on novel biodegradable segmented polyurethane as triggered delivery system for doxorubicin.

In this work, redox-sensitive polyurethane urea (PUU) based electrospun membranes have been exploited to chemically tether a pH-sensitive doxorubicin derivative achieved by linking a lipoyl hydrazide to the drug via a hydrazone linkage. First, the lipoyl-hydrazone-doxorubicin derivative labelled as LA-Hy-Doxo has been synthesized and characterized. Then, the molecule has been tethered, via a thiol-disulfide exchange reaction, to the redox-sensitive PUU (PolyCEGS) electrospun membrane. The redox-sensitive PolyCEGS PUU has been produced by using PCL-PEG-PCL polyol and glutathione-tetramethyl ester (GSSG-OMe)4 as a chain extender. The LA-Hy-Doxo tethered electrospun membrane has showed a dually controlled release triggered by acidic and reducing conditions, producing a significant cytotoxic effect in human breast cancer cell lines (MCF-7) which has validated the system for the post-surgical treatment of solid tumors to contrast recurrence.

Bioactive inks suitable for 3D printing based on waterborne polyurethane urea, cellulose nanocrystals and Salvia extract

This work explores the preparation of a bioactive ink suitable for direct ink writing (DIW) 3D printing by adding extract obtained from Salvia officinalis L. during the synthesis of a waterborne polyurethane urea (WBPUU). Additionally, to guarantee a successful printing performance, cellulose nanocrystals (CNC), a well-known rheology modulator, have been added after the synthesis process. In order to predict the behaviour of the inks in DIW, the rheological properties of the inks with and without the Salvia extract and the CNC have been studied. The results showed that the incorporation of Salvia extract into the WBPUU ink resulted in a decrease of the viscosity, yield point and storage modulus, obtaining an ink that cannot maintain the shape after being printed. On the contrary, the incorporation of the CNC into the WBPUU/Salvia ink increased the aforementioned rheological parameters leading to the obtaining of pieces presenting a good shape fidelity without compromising their printability. Finally, scaffolds were prepared from the printed pieces by freeze-drying technique and were tested against Gram negative Escherichia coli and Gram positive Staphylococcus aureus. The scaffolds containing CNC and Salvia showed bactericide behaviour against both bacteria, which was not seen in the WBPUU matrix, confirming the bioactive capacity of this ink.

Single-Ion Conducting Polymer Electrolytes Based on Random Polyurethane–Urea with Different Diisocyanate Structures for Lithium Batteries

Polyurethane–urea ionomers based on poly(ethylene oxide) (PEO) with various hard segment contents were synthesized from diisocyanates with different symmetries and planarities. The influence of the random copolymer microphase structure (including the phase separation morphology and hydrogen bonding behavior) on the ion states and ion migration was investigated. The soft phase could maintain a low glass transition temperature to yield samples with good ionic conductivity when the hard segment was less than 48 wt %. Furthermore, the hard phase and hydrogen bonds could provide good mechanical strength. Fourier transform infrared spectroscopy and small-angle X-ray scattering confirmed that ionomers with a smaller degree of phase separation had a high fraction of ions in isolated ion pairs. Coupled with faster segmental dynamics and ion mobility from the depressed Tg, the polyurethane–urea ionomer simultaneously showed high strength and ionic conductivity. After plasticization, the prepared single-ion conductor was successfully tested in lithium cells, demonstrating outstanding discharge capacity (166 mAh g–1), Coulombic efficiency (96.5%), and retention (92.6% after 100 cycles) at 0.1 C and high temperature.