Thermoplastic Elastomer Film Research Articles

The Hydrogen Bonding in the Hard Domains of the Siloxane Polyurea Copolymer Elastomers.

For probing the structure-property relationships of the polyurea elastomers, we synthesize the siloxane polyurea copolymer elastomer by using two aminopropyl-terminated polysiloxane monomers with low and high number-average molecular weight (Mn), i.e., L-30D and H-130D. To study the influence of the copolymer structures on the film properties, these films are analyzed to obtain the tensile performance, UV-vis spectra, cross-sectional topographies, and glass transition temperature (Tg). The two synthetic thermoplastic elastomer films are characterized by transparency, ductility, and the Tg of the hard domains, depending on the reacting compositions. Furthermore, the film elasticity behavior is studied by the strain recovery and cyclic tensile test, and then, the linear fitting of the tensile data is used to describe the film elasticity based on the Mooney-Rivlin model. Moreover, the temperature-dependent infrared (IR) spectra during heating and cooling are conducted to study the strength and recovery rate of the hydrogen bonding, respectively, and their influence on the film performance is further analyzed; the calculated Mn of the hard segment chains is correlated to the macroscopic recovery rate of the hydrogen bonding. These results can add deep insight to the structure-property relationships of the siloxane polyurea copolymer.

Sustainable grafting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and natural rubber into a new thermoplastic elastomer film

The rising environmental concerns have triggered film technology to find a bio-based polymer for environmental sustainability. Thus, this research provides a sustainable route for the preparation of new thermoplastic elastomer film based on non-polar natural rubber (NR) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx) which could be employed in film separation application. To modify the new film properties, graft copolymerization technique was employed, and benzoyl peroxide (BPO) was selected as a radical initiator. Besides that, the influence of various polymer compositions was investigated, and the physico-chemical characteristics of the NR graft P(3HB-co-3HHx) film were characterized. NR graft P(3HB-co-3HHx) exhibited homogeneous and porous nature with improved thermal stability as the grafting interaction between the polymer was achieved. Besides that, swelling test has shown the excellent resistance and affinity towards polar solvents such as ethanol, and it showcases lower affinity towards non-polar solvents as n-hexane was observed. Therefore, the NR graft P(3HB-co-3HHx) films can potentially be used for biofilm can be used for environmental remediation applications as a replacement to the synthetic polymer films.

Thermoplastic Elastomer (TPE)-Poly(Methyl Methacrylate) (PMMA) Hybrid Devices for Active Pumping PDMS-Free Organ-on-a-Chip Systems.

Polydimethylsiloxane (PDMS) has been used in microfluidic systems for years, as it can be easily structured and its flexibility makes it easy to integrate actuators including pneumatic pumps. In addition, the good optical properties of the material are well suited for analytical systems. In addition to its positive aspects, PDMS is well known to adsorb small molecules, which limits its usability when it comes to drug testing, e.g., in organ-on-a-chip (OoC) systems. Therefore, alternatives to PDMS are in high demand. In this study, we use thermoplastic elastomer (TPE) films thermally bonded to laser-cut poly(methyl methacrylate) (PMMA) sheets to build up multilayered microfluidic devices with integrated pneumatic micro-pumps. We present a low-cost manufacturing technology based on a conventional CO2 laser cutter for structuring, a spin-coating process for TPE film fabrication, and a thermal bonding process using a pneumatic hot-press. UV treatment with an Excimer lamp prior to bonding drastically improves the bonding process. Optimized bonding parameters were characterized by measuring the burst load upon applying pressure and via profilometer-based measurement of channel deformation. Next, flow and long-term stability of the chip layout were measured using microparticle Image Velocimetry (uPIV). Finally, human endothelial cells were seeded in the microchannels to check biocompatibility and flow-directed cell alignment. The presented device is compatible with a real-time live-cell analysis system.

Numerical Buckling Analysis of Hybrid Honeycomb Cores for Advanced Helmholtz Resonator Liners

In order to realize novel acoustic liners, honeycomb core structures specially adapted to these applications are required. For this purpose, various design concepts were developed to create a hybrid cell core by combining flexible wall areas based on thermoplastic elastomer films and rigid honeycomb areas made of fiber-reinforced thermoplastics. Within the scope of the presented study, a numerical approach was introduced to analyze the global compressive failure of the hybrid composite core structure, considering local buckling and composite failure according to Puck and Cuntze. Therefore, different geometrical configurations of fiber-reinforced tapes were compared with respect to their deformation as well as their resulting failure behavior by means of a finite element analysis. The resulting compression strength obtained by a linear buckling analysis agrees largely with calculated strengths of the more elaborate application of the failure criteria according to Puck and Cuntze, which were implemented in the framework of a nonlinear buckling analysis. The findings of this study serve as a starting point for the realization of the manufacturing concept, for the design of experimental tests of hybrid composite honeycomb core structures, and for further numerical investigations considering manufacturing as well as material specific aspects.

Self‐Strengthening Dielectric Elastomer of Triblock Copolymer with Significantly Improved Electromechanical Performance under Low Voltage

AbstractDielectric elastomer actuators (DEAs) are promising soft electromechanical transducers for soft robotics. Fabricating a high‐performance DEA actuated by sub‐kV voltage remains challenging. Here, a facile method not only to fabricate ultrathin dielectric elastomer films of triblock copolymers but also to enhance the dielectric breakdown strength and thus enhance the electromechanical performance is reported. A thick thermoplastic elastomer film of poly(styrene‐b‐butyl acrylate‐b‐styrene) from solution blading is symmetrically pre‐stretched and relaxed at 120 °C to fabricate a freestanding ultrathin DE film. Compared with the pristine DE film of the same thickness (12 µm), the thermally‐relaxed DE film with equally biaxial pre‐stretch ratio 3.5 × 3.5 exhibits increased electrical breakdown strength by a factor of 1.9 (from 43 to 82 V µm−1), maximum actuation area strain by a factor of 1.9 (from 11.7% to 22.4%), and highest energy density by a factor of 5.7 (from 4.5 to 25.8 kJ m−3). The enhancement may be ascribed to the self‐reinforcement of the dielectric breakdown strength due to the morphology change of polystyrene nanodomains from spheres to oblate spheroids. Thanks to the ultra‐thinness, the high electromechanical performance is achieved within sub‐kV driving voltage in all cases.

Reversible Bonding of Thermoplastic Elastomers for Cell Patterning Applications

In this paper, we present a simple, versatile method that creates patterns for cell migration studies using thermoplastic elastomer (TPE). The TPE material used here can be robustly, but reversibly, bonded to a variety of plastic substrates, allowing patterning of cultured cells in a microenvironment. We first examine the bonding strength of TPE to glass and polystyrene substrates and com-pare it to thermoset silicone-based PDMS under various conditions and demonstrate that the TPE can be strongly and reversibly bonded on commercially available polystyrene culture plates. In cell migration studies, cell patterns are templated around TPE features cored from a thin TPE film. We show that the significance of fibroblast cell growth with fetal bovine serum (FBS)-cell culture media compared to the cells cultured without FBS, analyzed over two days of cell culture. This simple approach allows us to generate cell patterns without harsh manipulations like scratch assays and to avoid damaging the cells. We also confirm that the TPE material is non-toxic to cell growth and supports a high viability of fibroblasts and breast cancer cells. We anticipate this TPE-based patterning approach can be further utilized for many other cell patterning applications such as in cell-to-cell communication studies.

Photodynamic Polymers as Comprehensive Anti-Infective Materials: Staying Ahead of a Growing Global Threat.

To combat the global threat posed by surface-adhering pathogens that are becoming increasingly drug-resistant, we explore the anti-infective efficacy of bulk thermoplastic elastomer films containing ∼1 wt % zinc-tetra(4- N-methylpyridyl)porphine (ZnTMPyP4+), a photoactive antimicrobial that utilizes visible light to generate singlet oxygen. This photodynamic polymer is capable of inactivating five bacterial strains and two viruses with at least 99.89% and 99.95% success, respectively, after exposure to noncoherent light for 60 min. Unlike other anti-infective methodologies commonly requiring oxidizing chemicals, carcinogenic radiation, or toxic nanoparticles, our approach is nonspecific and safe/nontoxic, and sustainably relies on the availability of just oxygen and visible light.

Facile Method and Novel Dielectric Material Using a Nanoparticle-Doped Thermoplastic Elastomer Composite Fabric for Triboelectric Nanogenerator Applications.

The trends toward flexible and wearable electronic devices give rise to the attention of triboelectric nanogenerators (TENGs) which can gather tiny energy from human body motions. However, to accommodate the needs, wearable electronics are still facing challenges for choosing a better dielectric material to improve their performance and practicability. As a kind of synthetic rubber, the thermoplastic elastomer (TPE) contains many advantages such as lightweight, good flexibility, high tear strength, and friction resistance, accompanied by good adhesion with fabrics, which is an optimal candidate of dielectric materials. Herein, a novel nanoparticle (NP)-doped TPE composite fabric-based TENG (TF-TENG) has been developed, which operates based on the NP-doped TPE composite fabric using a facile coating method. The performances of the TENG device are systematically investigated under various thicknesses of TPE films, NP kinds, and doping mass. After being composited with a Cu NP-doped TPE film, the TPE composite fabric exhibited superior elastic behavior and good bending property, along with excellent flexibility. Moreover, a maximum output voltage of 470 V, a current of 24 μA, and a power of 12 mW under 3 MΩ can be achieved by applying a force of 60 N on the TF-TENG. More importantly, the TF-TENG can be successfully used to harvest biomechanical energy from human body and provides much more comfort. In general, the TF-TENG has great application prospects in sustainable wearable devices owing to its lightweight, flexibility, and high mechanical properties.

Tribological properties investigation of the thermoplastic elastomers surface with the AFM lateral forces mode

The series of new thermoplastic elastomer films based on copoly(urethane-imide)s (coPUI)s and nanocomposites containing from 1 to 10 wt. % carbon nanofillers of different morphology (single-walled carbon nanotubes, carbon nanofibers, and graphene) as well as WS2 and WSe2 nanoparticles, were prepared and investigated by atomic force microscopy in contact mode. The friction coefficient (Cfr) on the films surfaces under conditions of true slip was determined both in one scan field and with multiple scans (200-400) in one place. The measurements were carried out at room temperature and at a heating up to 120°C. It is shown that at heating up to 75-85°C, the friction coefficient of some coPUI decreases significantly. The same effect can be achieved also after 100 scans during multi-scan testing at 20°C.

Strain-Induced Deformation of Glassy Spherical Microdomains in Elastomeric Triblock Copolymer Films: Time-Resolved 2d-SAXS Measurements under Stretched State

We have found extremely low efficiency of the elastomeric properties for SEBS (polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene) triblock copolymers having short polystyrene (PS) block chains. Since the SEBS specimens form spherical PS microdomains embedded in the matrix of the rubbery poly(ethylene-co-butylene) (PEB) chains, they exhibit elastomeric properties (thermoplastic elastomer film). However, it was found that the stress was dramatically decreased with time when the specimens were stretched and fixed at strain of 4.0. Furthermore, they showed macroscopic fracture with very short-term duration (400 s to 2 h). To reveal the reason for such low efficiency, we conducted time-resolved two-dimensional small-angle X-ray scattering (2d-SAXS) measurements for the SEBS triblock copolymer films under stretched state at strain of 4.0. Upon stretching, the strain-induced deformation (not fracture) of glassy microdomains was observed. In addition, the deformation of glassy microdomains was found ...

Strain-Induced Deformation of Glassy Spherical Microdomains in Elastomeric Triblock Copolymer Films: Simultaneous Measurements of a Stress–Strain Curve with 2d-SAXS Patterns

Thermoplastic elastomers are elastomeric materials which contain hard domains as physical cross-linking for rubbery chains. Therefore, the hard domains are required permanently rigid. Nevertheless, we have found experimentally deformation of the hard domains upon uniaxial stretching of the thermoplastic elastomer films. In this paper, we report experimental results of deformation of glassy spherical microdomains in elastomeric triblock copolymer films upon uniaxial stretching, as revealed by two-dimensional small-angle X-ray scattering (2d-SAXS) measurements. Actually, shifts of the peak position of the particle scattering toward lower and higher q-regions were detected for q directions parallel and perpendicular to the stretching direction (SD), respectively, where q stands for the scattering vector. By assuming that spheres simply deformed into prolate spheroids with its major axis parallel to SD, 1d-SAXS profiles measured at several strains were successfully reproduced with model calculation of the 1d-SAXS profile. From the results of model calculation, radii of the prolate spheroids were appropriately determined. Since the extent of the deformation of microdomains was found to increase as the initial size of microdomains decreased, it is concluded that the deformation of glassy microdomains may be due to a high extent of the stress concentration at microdomains. Upon unloading, the deformed particle scattering peak in the 2d-SAXS pattern was found to retrieve almost a round shape. At a glance, this fact implies that the deformed sphere (prolate spheroid) recovers an isotropic shape. However, this kind of the elastic behavior cannot be the case for the glassy domain. Alternatively, we have tried to explain the change of the 2d-SAXS pattern by orientational relaxation of the prolate spheroids without changing the shape of the prolate spheroids. It was found that such trial was sound.

Thermal bonding of thermoplastic elastomer film to PMMA for microfluidic applications

Styrenic butadiene block copolymer thermoplastic elastomer films (TPE) have been developed as an alternative to polydimethylsiloxanes (PDMS) for microfluidic applications. The integration of the TPE film to thermoplastic poly(methyl methacrylate) (PMMA), which is a critical step in microfluidic microfabrication process, has been performed by direct thermal bonding. It is found that surface treatment by plasma, in particular O2 plasma, prior to bonding has significant effect in increasing hydrophilicity and bonding strength between the TPE film and PMMA. Moreover, the O2 plasma treatment performed on surface of the TPE film is found to be much more effective in enhancing the bonding strength than on the PMMA. Using optimized bonding conditions, thermal bonding between the TPE film and PMMA chip has been achieved at low pressure and the microchannel integrity in the bonded joint is well retained with negligible clogging. Additionally, the effect of bonding temperature of 80°C on mechanical properties of the TPE film has been studied through ageing test. The tensile strength and modulus of the TPE film do not change significantly even after 24h ageing at 80°C.

Computer.assisted thermoplastic elustomer film localization system for screw insertion to fix posterior column of acetabulum

Objective To assess accuracy and efficacy of the mini-invasive screw insertion for fix-ation of the posterior column of acetabulum by the computer-assisted thermoplastic elastomer film localization system. Methods In a simulated surgical setup, 20 cannulated screws were placed into the posterior column of acetabulum in 10 corpses under the guidance of the computer-assisted thermoplastic elastomer film localization system. The positions of the screws were checked with CR and CT. Results All the 20 screws were in the safe area. Radiation exposure was totally avoided. Conclusion The system can pro-vide precise, effective and safe navigation for screw insertion to fix the posterior column of acetabulum, and markedly prevent the patient and the staff from exposure to the radiation. Key words: Surgery, computer-assisted; Thermoplastic elastomer film localization system; Acetabulum; Screws

Superstructual Changes during Uniaxial Deformation of Thermoplastic Elastomer Films

Superstructual Changes during Uniaxial Deformation of Thermoplastic Elastomer Films

JSR develops thermoplastic elastomer film grade

Crystallization and phase behavior in solution-cast thin films of crystalline syndiotactic 1,2-polybutadiene (s-1,2-PB) and isotactic polypropylene (i-PP) blends have been investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) techniques. Thin films of pure s-1,2-PB consist of parallel lamellae with the c-axis perpendicular to the film plane and the lateral scale in micrometer size, while those of i-PP are composed of cross-hatched and single-crystal-like lamellae. For the blends, TEM and AFM observations show that with addition of i-PP, the s-1,2-PB long lamellae become bended and i-PP itself tends to form dispersed convex regions on a continuous s-1,2-PB phase even when i-PP is the predominant component, which indicates a strong phase separation between the two polymers during film formation. FESEM micrographs of both lower and upper surfaces of the films reveal that the s-1,2-PB lamellae pass through i-PP convex regions from the bottom, i.e. the dispersed i-PP regions lie on the continuous s-1,2-PB phase. The structural development is attributed to an interplay of crystallization and phase separation of the blends in the film forming process. With solvent evaporation, s-1,2-PB would crystallize first forming the continuous phase, while the segregated i-PP phase accumulated on s-1,2-PB and crystallized subsequently, forming dispersed i-PP regions.

Radiation Cured, Thermoplastic Elastomer Films Based on "Macromolecular Monomers" for Heat Activated Adhesives

Radiation curable, 100% convertible liquid formulations based on "Macromolecu lar Monomers" perform as thermoplastic elastomers when polymerized by ultraviolet light or electron beam radiation. Dissolved in acrylate monomer bases, these films are flexible, tack-free and perform admirably as heat activated adhesives. Suitable macromolecular monomers (macromonomers) are high molecular weight polystyryl polymers that are terminated at only one end with a functional methacrylate end-group.

Electrically conductive thermoplastic elastomer/polyacetylene blends

Three different types of thermoplastic elastomers, styrenebutadiene-styrene, styrene-isoprene-styrene, and styreneethylenebutylene-styrene triblock copolymers have been blended with polyacetylene utilizing various blending techniques. In one method, acetylene gas was polymerized with the Ziegler-Natta catalyst in the presence of either the thermoplastic elastomer film or a hydrocarbon solution of the thermoplastic elastomer. The resulting polyacetylene/thermoplastic elastomer blend has been characterized with infrared spectroscopy, X-ray diffraction and electron microscopy. Upon doping with either iodine or ferric chloride, the ultimate conductivities of the blends were found to be 60–100 Ω−1 cm−1.