Blending thermoplastic polyurethanes and poly(ethylene oxide) for composite electrolytes via a mixture design approach

With the aim of obtaining proper composite electrolytes, a systematic modeling analysis for the percentage increase in weight due to swelling with respect to swollen weight, S_w, and the room temperature conductivity (σ₂₅) of the composite films of polyethylene glycol based thermoplastic polyurethane/polytetramethylene glycol based thermoplastic polyurethane/polyethylene oxide [denoted as TPU(PEG)/TPU(PTMG)/PEO] was performed. Using a mixture design approach, empirical models are fitted and plotted as contour diagrams which facilitate revealing the synergistic/antagonistic effects among the mixed polymers. The contour plot results show that both the maximum S_w (64.9%) and the maximum σ₂₅ (72.2 × 10⁻⁵ S cm⁻¹) appear at point X₃ (PEO 85%, TPU(PEG) 15%). The results are reasonably explained from the interactions among polymers on the basis of their molecular structures. The thermal analysis of the composite films is performed to demonstrate the speculations about the interactions among the mixed polymers by using differential scanning calorimeter. The crystallization of PEO spherulites at different compositions was examined by using a polarizing microscope. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 680–692, 2000     

Free volume properties of thermoplastic polyurethane/polymethylmethacrylate blends: Evidence of interchain interaction

A polymer blend based on thermoplastic elastomeric polyurethane and polymethylmethacrylate (TPU/PMMA) has been studied by positron annihilation lifetime spectroscopy (PALS) and thermomechanical analysis. Thermomechanical analysis allowed the determination of two glass transitions for the blends in the overall range of compositions. The first one (T_g¹) showed a constant value of ?45°C for all blends, the same value of the pure TPU. The second glass transition (T_g²), which is associated with a PMMA rich phase, presented variations with composition. T_g² showed minimum values for the blends in the 20–40 wt % TPU range, which indicates increase of interaction in this composition region. PALS systematic investigation allowed the determination of relative mean free volume fractions, f_v/C, and binary interchain interaction parameters, β. These parameters exhibited a noticeable negative deviation from additivity in all range of composition and minima for the 20 wt % TPU blend. PALS results were interpreted as associated to a strong attractive interchain interaction between TPU and PMMA in the PMMA rich phase which contracts the free volume fraction of the blends. Moreover, the miscibility achieved in the PMMA rich phase would allow a good adhesion between this phase and the TPU phase, which was corroborated by scanning electron microscopy images. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The influence of filler treatment on the properties of TPU/PP blends: I. Thermal properties and stability

Commercially available organosilane (3‐glycidoxypropyltrimethoxysilane (GPTMS)) coupling agent was used to treat talc in order to improve the affinity relative between the filler and the polymer in composites as well as filler and polymer in the thermoplastic polyurethane/polypropylene (TPU/PP) blends (talc content was 5 wt%). The talc particles were first modified with GPTMS and then introduced into TPU, PP as well as TPU/PP blends with different weight ratios of polymers using blending method and subsequently injection molded in a hydraulic press. The aim was to report the effect of silane coupling agent on the thermal and morphological properties of talc filled composites and blends. The results showed that the thermal properties of the TPU, PP composites and TPU/PP blends were improved with the addition of silane treated talc (higher melting (T_m), crystallization (T_c) temperatures and degree of crystallinity (χ_c)). The glass transition temperature (T_g) obtained by dynamic mechanical analysis (DMA) of the TPU soft segments in TPU/PP blends increased with the addition of untreated and silane treated talc due to lower mobility of the soft segments in TPU and better miscibility of TPU and PP. TPU/PP blends with the silane treated talc show better thermal stability than the TPU/PP blends with untreated talc. POLYM. ENG. SCI., 55:1920–1930, 2015. © 2014 Society of Plastics Engineers     

A novel electrospun TPU/PVdF porous fibrous polymer electrolyte for lithium ion batteries

Novel blend-based gel polymer electrolyte (GPE) films of thermoplastic polyurethane (TPU) and poly(vinylidene fluoride) (PVdF) (denoted as TPU/PVdF) have been prepared by electrospinning. The electrospun thermoplastic polyurethane-co-poly (vinylidene fluoride) membranes were activated with a 1M solution of LiClO₄ in EC/PC and showed a high ionic conductivity about 1.6 mS cm⁻¹ at room temperature. The electrochemical stability is at 5.0 V versus Li⁺/Li, making them suitable for practical applications in lithium cells. Cycling tests of Li/GPE/LiFePO4 cells showed the suitability of the electrospun membranes made of TPU/PVdF (80/20, w/w) for applications in lithium rechargeable batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Morphology control of polyoxy‐methylene/thermoplastic polyurethane blends by adjusting their viscosity ratio

Polyoxymethylene (POM) is an important plastic with very good properties. However, its poor impact strength limits its applications. Theoretical and experimental studies have confirmed that thermoplastic polyurethane (TPU) can effectively enhance the notched impact strength of POM. This paper reports that the notched impact strength of POM/TPU blends can be further improved when these blends are endowed with a fine morphology by changing the viscosity ratio of TPU to POM (P = η_TPU/η_POM) during processing. The experimental results show that the viscosity of TPU is more sensitive to temperature than that of POM, and that the viscosity ratio P decreases with increasing temperature; also for quite a wide range of shear rate, P is close to 1 when the processing temperature (T_p) is around 190 °C. Accordingly, the phase structure of POM/TPU blends changes with P. The dispersed phase of TPU shows ellipsoidal morphology when P > 1 at T_p < 190 °C, filamental morphology when P ≈ 1 at T_p ≈ 190 °C and spheroidal morphology when P < 1 at T_p > 190 °C. The results suggest that the filamental morphology endows POM/TPU (90/10) blends with the highest notched impact strength (～14 kJ m^?2). Copyright © 2006 Society of Chemical Industry     

Thermoplastic polyurethane elastomer induced shear piezoelectric coefficient enhancement in bismuth sodium titanate – PVDF composite films

A series of ester-based thermoplastic polyurethane elastomer (TPU) and bismuth sodium titanate polycrystalline oxide (Bi_0.5Na_0.5TiO₃, BNT) co-blended poly (vinylidene fluoride) (PVDF) composite films were prepared. Mechanical test confirms the optimum BNT blending content (25 wt%) and further reveals a linear growth of tensile elongation by increasing TPU content. Microstructure modifications including strengthened hydrogen bond and valence band edge elevation are evidenced to be highly correlated to the dielectric and piezoelectric properties. Significant enhancement (7–13 times) in face shear piezoelectric coefficient (d₃₆) is achieved by adjusting the blending content of TPU. Cross-section image presents a featuring multilayer structure with improved dispersity of BNT particle under a transverse tensile force which effectively increases the interfacial contact area between BNT and polymer blends. This work reveals the significance of band structure modification and anisotropic texture construction on influencing the transfer of piezoelectric charge in TPU blended BNT-PVDF composite film.     

Bio‐based thermoplastic polyurethane and polyamide 11 bioalloys with excellent shape memory behavior

Bio‐based blends of commercially available polyester based bio thermoplastic polyurethane (TPU) and castor oil based polyamide 11 (PA11) of different ratios are prepared by melt processing. The blends properties such as shape memory behavior through unconstrained and constrained recovery, interfacial interaction, morphology, dynamic mechanical, rheological, and mechanical behavior are studied. A strong interface between the two polymeric phases due to hydrogen bonding observed through morphology indicates that TPU and PA11 are well compatible. The complex viscosity of blends ranges between that of neat PA11 and TPU. Thermal analysis shows that higher the TPU content lower the melting point (T_m ) corresponding to PA11 and the crystallization temperature (T_c ) remains unaltered. Adding TPU to PA11 ductility and impact strength of the blends increases significantly with the small reduction in their tensile strength. Shape memory behavior investigation reveals that, blends recover almost 95% of the applied deformation when heated at zero load and they recovered a stress of 1.8–3.2 MPa in constrained recovery during three consecutive thermomechanical cycles. The reported results on bioalloys promotes the usage in multidisciplinary field of intelligent devices, such as ergonomic grips and sports shields. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44794.     

Factors affecting the durability of Ca-complexed methylmethacrylate copolymer films containing CaO–SiO2–H2O macromolecules

A CaO–SiO₂–H₂O macromolecular–ionomer complex was found to be formed in the superficial layers of MMA–TMPTMA copolymer composite films made with filler containing hydraulic cement during exposure in an autoclave at temperatures up to 200°C. This complex acted to prevent the hydrothermal deterioration of the original composite films, which is important if the films are used as protective layers on metals. This complex also contributed significantly to hydrophobicity, a low energy surface, and less surface roughness, thereby lowering the intrinsic water permeability of the films. The glass transition temperature T_g and the tensile strength of the complexed films increased with increasing concentration of the cement additive used as a source of Ca²⁺ metallic ions, but they decreased when the cement concentration became excessive because of the chain enlargement caused by the growth of a large quantity of hydrated macromolecules. Ca^2? ions were found to migrate from the cement grains in an aqueous medium and to have a crosslinking function connecting the oxidized metal surfaces and the functional carboxylate groups located in the pendent parts of the polymer molecules. The resultant shear bond strength of metal-to-metal lap joint specimens after exposure for 3 days to water at 150°C was twice as high as that for the samples made without cement.     

Composite polymer electrolytes based on electrospun thermoplastic polyurethane membrane and polyethylene oxide for all‐solid‐state lithium batteries

To improve the electrochemical properties and enhance the mechanical strength of solid polymer electrolytes, series of composite polymer electrolytes (CPEs) were fabricated with hybrids of thermoplastic polyurethane (TPU) electrospun membrane, polyethylene oxide (PEO), SiO₂ nanoparticles and lithium bis(trifluoromethane)sulfonamide (LiTFSI). The structure and properties of the CPEs were confirmed by SEM, XRD, DSC, TGA, electrochemical impedance spectroscopy and linear sweep voltammetry. The TPU electrospun membrane as the skeleton can improve the mechanical properties of the CPEs. In addition, SiO₂ particles can suppress the crystallization of PEO. The results show that the TPU‐electrospun‐membrane‐supported PEO electrolyte with 5 wt% SiO₂ and 20 wt% LiTFSI (TPU/PEO‐5%SiO₂‐20%Li) presents an ionic conductivity of 6.1 × 10^?4 S cm^?1 at 60 °C with a high tensile strength of 25.6 MPa. The battery using TPU/PEO‐5%SiO₂‐20%Li as solid electrolyte and LiFePO₄ as cathode shows an attractive discharge capacity of 152, 150, 121, 75, 55 and 26 mA h g^?1 at C‐rates of 0.2C, 0.5C, 1C, 2C, 3C and 5C, respectively. The discharge capacity of the cell remains 110 mA h g^?1 after 100 cycles at 1C at 60 °C (with a capacity retention of 91%). All the results indicate that this CPE can be applied to all‐solid‐state rechargeable lithium batteries. © 2018 Society of Chemical Industry     

Preparation and characterization of novel transparent Eu(AA)3-polyurethane acrylate copolymeric materials

The rare earth (RE) salts Eu(AA)₃ (AA: acrylic acid group) and the macromonomers of polyurethane acrylate (MPUA) containing vinyl groups at the end of the chain are prepared for achieving a novel transparent Eu(AA)₃-polyurethane acrylate (Eu-PUA) materials by copolymerization. The structure and properties of the Eu(AA)₃ and the Eu-PUA have been systematically characterized by infrared spectroscopy (FTIR), proton and carbon nuclear magnetic resonance (¹H-NMR, ¹³C-NMR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and fluorescence spectrophotometer. It is proved that the Eu(AA)₃ have been successfully bonded onto the molecular chains of the polyurethane acrylate and the glass transition temperature (T_g) of the polyurethane acrylate increases at the presence of Eu(AA)₃. In addition, the Eu-PUA materials show favorable thermal stability and transparence. Typically, the fluorescence spectra show that the strongest fluorescence emission peak of the Eu-PUA material appears at 614 nm at the excitation wavelength of 395 nm. This demonstrates that such material can be applied to functional optical materials in the future. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Dynamic mechanical properties of poly(vinyl chloride) and polyurethane carboxylate blends

The miscibility of thermoplastic polyurethane elastomers (TPUs) with poly(vinyl chloride) (PVC) was studied. PVC blends with TPUs, prepared from 4,4-diphenylmethane diisocyanate as diisocyanate, hydroxy-terminated poly(butylene adipate) (PBA) as the soft segment, and dimethylolpropionic acid as the chain extender carrying a latent anionic site for neutralization by triethylamine, showed a single glass transition temperature (T_g), irrespective of neutralization of latent anionic sites of TPU. But in neutralized TPU/PVC blends, limited intimate segmental mixing was perceived from the mechanical properties observed. When hydroxy-terminated poly(propylene glycol) was used as the soft segment instead of hydroxy-terminated PBA, PVC/TPU blends showed two separate T_g's of PVC and TPU, irrespective of neutralization. © 1994 John Wiley & Sons, Inc.     

Electromagnetic interference shielding behavior of chemically and thermally reduced graphene based multifunctional polyurethane nanocomposites: A comparative study

This article presents the effect of exfoliation, dispersion, and electrical conductivity of graphene sheets onto the electrical, electromagnetic interference (EMI) shielding, and gas barrier properties of thermoplastic polyurethane (TPU) based nanocomposite films. The chemically reduced graphene (CRG) and thermally reduced/annealed graphene (TRG) having Brunauer–Emmett–Teller surface areas of 18.2 and 159.6 m²/g, respectively, when solution blended with TPU matrix using N,N-dimethylformamide as a solvent. Graphene sheets based TPU nanocomposites have been evaluated and compared for EMI shielding in Ku band, electrical conductivity, and gas barrier property. TRG/TPU nanocomposite films showed excellent gas barrier against N₂ gas as compared to CRG/TPU. The EMI shielding effectiveness for neat CRG and TRG graphene sheets is found to be −80, −45 dB, respectively, at 2 mm thickness. The EMI shielding data revealed that TRG/TPU nanocomposites showed better shielding at lower concentration (10 wt %), while CRG displayed better attenuation at higher concentrations. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47666.     

In situ fluorescence experiments for real-time monitoring of annealed high-T latex film dissolution

A new technique, based on steady-state fluorescence measurements, is introduced for studying dissolution of polymer films. These films are formed from naphthalene and pyrene labeled poly(methyl methacrylate) (PMMA) latex particles, sterically stabilized by polyisobutylene. Diffusion of solvent (chloroform) into the annealed latex film was followed by desorption of polymer chains. Annealing was performed above T_g at various temperatures for 30-min time intervals. Desorption of pyrene labeled PMMA chains was monitored in real time by the pyrene fluorescence intensity change. Desorption coefficients were found to be between 1 and 4 × 10⁻¹⁰ cm²/s and two different dissolution mechanisms were detected. © 1996 John Wiley & Sons, Inc.     

High-performance PA1/TPU films with enhanced dielectric constant and low loss tangent

Polymer composites with high dielectric constant are promising materials for energy-storage application. However, their development has generally been hindered due to the challenge to balance dielectric constant and loss tangent. In this work, a novel thermoplastic polyurethane (TPU)-based composite with high dielectric constant and low loss tangent was prepared by inducing polyamide-1(PA1). The optimal content of PA1 in TPU matrix was 1.0 wt %. Importantly, the dielectric constant of TPU exhibited great stability at the frequency range of 10³–10⁶ Hz and increased sharply with the addition of PA1. In specific, the dielectric constant of TPU increased from 8 to 41 with the incorporation of 1.0 wt % PA1, which was five times higher than that of pure TPU. Meanwhile, the loss tangent still kept at a low level of less than 0.02. This work may provide a new direction for preparation of dielectric polymer composites with excellent comprehensive performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48469.     

Single-ion conduction in UV-crosslinked films of poly(urethane-co-(alkali-metal methacrylates))

A series of crosslinked copolymers of poly(ethylene glycol-co-2,4-tolyl diisocyanate-co-(alkali-metal methacrylates)) were prepared by copolymerization of polyurethane oligomer with alkali-metal methacrylate. Cast films of these copolymers obtained by UV-crosslinked polymerization are completely amorphous and have a relatively low T_g. The films provide good mechanical properties and high ionic conductivity without additional solvent or inorganic salts. DC ionic conductivity of the films at room temperature is stable over time indicating that the copolymer is a cationic single-ion conductor. AC conductivity of these films depends mainly on the ionic radius, segmental motion of the polymer chains and local environment of the ions in the polymer matrix.     

The dependence of morphology of solid polymer electrolyte membranes on transient salt type: effect of cation type

The structures of poly(N‐vinyl pyrrolidone) (PVP) and poly(ether sulfone) composite membranes were investigated with transient salt addition. The effects of type and concentration of AgNO₃ and Cu(NO₃)₂ on membrane morphology were evaluated through attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy, differential scanning calorimetry (DSC) and atomic force microscopy. Complex formation between carbonyl groups (on PVP chains) and Cu²⁺ or Ag⁺ decreases the strength of the carbonyl bond as evidenced through ATR‐FTIR spectroscopy. The results indicate that the copper salts create more powerful interactions than the silver salts in the polymer matrix. DSC experiments reveal that the glass transition temperature of polymeric films containing silver or copper cations is lower than that of the PVP reference film. Comparison of the thermograms of PVP + AgNO₃ and PVP + Cu(NO₃)₂ shows that copper ions disrupt the polymer crystallinity more than silver ions. Therefore, DSC observations confirm the ATR‐FTIR results in the case of the strength of the complexes formed. A morphological analysis of membrane surfaces reveals the existence of electrostatic interactions in the polymeric membrane structure. This is a result of the addition of salt to the casting solution, wrinkling the polymer chains including the surface layer, and accordingly the surface of the facilitated transport membranes is rougher than the initial PVP membrane. Copyright © 2010 Society of Chemical Industry     

Circular Dichroism and Circular Polarized Luminescence from a Green Fluorescent Protein—Initial Research for Chiroptical Emission of Biological Materials

Optical properties of a green fluorescent protein (GFP) are examined using optical absorption, circular dichroism (CD), and circular polarized luminescence (CPL) spectroscopies. The GFP has chiroptical activity and exhibits green circular polarized emission, although the g _em-factor is small. Poly(vinyl alcohol) (PVA)/GFP composite films are prepared to attempt long-term preservation of the GFP emission activity. After five years, the transparent PVA/GFP composite film still exhibits stable fluorescence that appears similar to the emission from the Aequorea jellyfish.     

Multiwavelength interferometry and competing optical methods for the thermal probing of thin polymeric films

Multiple‐wavelength interferometry (MWI), a new optical method for the thermal probing of thin polymer films, is introduced and explored. MWI is compared with two standard optical methods, single‐wavelength interferometry and spectroscopic ellipsometry, with regard to the detection of the glass transition temperature (T_g) of thin supported polymer films. Poly(methyl methacrylate) films are deposited by spin coating on Si and SiO₂ substrates. MWI is also applied to the study of the effect of film thickness (25–600 nm) and polymer molecular weight (1.5 × 10⁴ to 10⁶) on T_g, the effect of film thickness on the coefficients of thermal expansion both below and above T_g, and the effect of deep UV exposure time on the thermal properties (glass transition and degradation temperatures) of the films. This further exploration of the MWI method provides substantial insights about intricate issues pertinent to the thermal behavior of thin polymer films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4764–4774, 2006     

Synthesis and characterization of in situ polymerized segmented thermoplastic elastomeric polyurethane/layered silicate clay nanocomposites

Nanocomposites based on thermoplastic elastomeric polyurethane (TPU) and layered silicate clay were prepared by in situ synthesis. The properties of nanocomposites of TPU with unmodified clay were compared with that of organically modified clay. The nanocomposites of the TPU and organomodified clay showed better dispersion and exhibited superior properties. Exfoliation of the clay layers was observed at low organoclay contents, whereas an intercalated morphology was observed at higher clay contents. As one of major purposes of this study, the effect of the silicate layers in the nanocomposites on the order–disorder transition temperature (T_ODT) of the TPU was evaluated from the intensity change of the hydrogen‐bonded and free carbonyl stretching peaks and from the peak position change of the N? H bending peak. The presence of the organoclay increased T_ODT by approximately 10°C, which indicated improved stability in the phase‐separated domain structure. The layered silicate clay caused a tremendous improvement in the stiffness of the TPU; meanwhile, a reduction in the ultimate elongation was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3048–3055, 2006     

Flexible poly(styrene-ethylene-butadiene-styrene) hybrid nanofibers for bioengineering and water filtration applications

Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO₂) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application.