Styrene Ethylene Butylene Research Articles

Flexible composite phase change material with enhanced thermophysical, dielectric, and mechanical properties for battery thermal management

A flexible composite phase change material (FCPCM) reduces thermal contact resistance in battery thermal management systems (BTMSs), thereby improving heat transfer efficiency. However, its high electrical and low thermal conductivity hinders its application to cooling lithium-ion batteries. Herein, a type of FCPCM with well-retained flexibility as well as high electrical insulation and thermal conductivity is prepared by mixing paraffin (PA), styrene ethylene butylene styrene (SEBS), and hexagonal boron nitride (h-BN). The chemical, thermophysical, and mechanical properties, as well as the physical structure of the FCPCM are analyzed. The components (PA/SEBS/BN) show good physicochemical compatibility without chemically reacting. The shore hardness of the proposed FCPCM decreases from 80 to 9 HA as the temperature increases from 20 to 80 °C, and it can be easily stretched or bended beyond the melting point of PA. Moreover, this composite possesses large latent heat (127.8 J/g), high thermal conductivity (2.7 W/(m·K)), sufficient volume resistivity (20,106 Ω·m), and suitable phase change temperature (41.1 °C). With such exceptional qualities, it shows outstanding applicability and cooling performance in cylindrical and prismatic batteries. Temperature and temperature difference of the prismatic battery pack can be restrained below 45 °C and 4 °C, even at a high discharge rate of 6 C and an ambient temperature of 38 °C.

Development and characterization of surface functionalized hierarchical carbon fiber reinforced hybrid polypropylene composites

Light-weight hybrid composites of relevant industrial applications were prepared using surface functionalized hierarchical carbon fibers ( f-CF), silane treated hollow glass microspheres (HGM), and a blend of polypropylene (PP) and maleic anhydride-grafted-styrene ethylene butylene styrene as the base polymer matrix. The f-CF were prepared by coating amine functionalized carbon nanotubes onto silane treated CF using an ultrasonic assisted electrophoretic deposition technique to improve fiber-matrix interfacial adhesion. For hybrid composition of 20 wt.% f-CF and 10 wt.% HGM, the tensile strength and modulus improved by ∼141 and ∼536% over neat PP while flexural strength and modulus increased by ∼118% and ∼583% respectively. Impact strength of 11.06 kJ/m2 was obtained and uniform dispersion and distribution of f-CF and HGMs was observed in Scanning electron microscope (SEM) images. Desirable reduction in density and melt viscosity along with improvement in composite stiffness were observed due to addition of HGM filler. Compared to PP, the crystallization temperature increased by ∼12°C while a maximum decrease of ∼5°C in melting temperature was obtained for the hybrid composites. Crystallinity of the hybrid composites decreased with an evident β crystal formation brought in by the nucleation.

Synthesis and investigation of form-stable myristic acid based composite phase change material containing styrene ethylene butylene styrene with enhanced properties for thermal energy storage

To overcome the challenges of low thermal conductivity and leakage of fatty acid based phase change materials (PCMs), a high-efficiency form-stabilized composite, with the use of styrene ethylene butylene styrene (SEBS) as structure material, was prepared and investigated in this work. The myristic acid (MA) was used as PCM and graphite was employed as thermal conductivity enhancer to improve composite thermal conductivity. A series of characterizations were performed to investigate the composite microstructure, chemical compatibility and thermal properties. Furthermore, the thermal conductivity and mechanical strength enhancement of the composite were evaluated by dispersing of high density polyethylene (HDPE). The results showed an excellent chemical compatibility in the composite. The MA can be uniformly dispersed in the SEBS matrices and 15 wt% SEBS endowed the composite with the capacity to maintain structure stabilization. The Differential Scanning Calorimetry and Laser Flash Analyser results revealed that the MA/SEBS/graphite composite with a mass ratio of 85:15:10 presented a constant melting temperature around 53 °C, high latent heat of 150.33 kJ/kg and high thermal conductivity of 0.655 W/m·K. The composite thermal conductivity and mechanical strength can be further enhanced by adding of HDPE and a loading of 5 wt% HDPE achieves the enhancement of the composite thermal conductivity and mechanical strength respectively by 25.4% and 16.4%.

TFC organic solvent nanofiltration membrane fabricated by a novel HDPE membrane support covered by manganese dioxide /tannic acid-Fe3+layers

BackgroundIt is of great importance to select an ultrafiltration (UF) support with outstanding solvent stability to fabricate thin film composite (TFC) organic solvent nanofiltration (OSN) membranes. MethodsHigh density polyethylene (HDPE)-polystyrene (PS)-styrene-ethylene-butylene-styrene (SEBS) blends were prepared through the incorporation of different SEBS weight percentages. Next, HDPE membranes were made via extracting the dispersed phase from the HDPE/PS/SEBS blends using THF. Then, the membrane with the optimum properties was selected as the support for preparing the TFC membranes. Accordingly, the support was first contacted with KMnO4 solution, by which MnO2 nanoparticles (NPs) were generated on the support surface. The membrane surface was then contacted with tannic acid (TA) and FeCl3 aqueous solutions consecutively to form a uniform TA-Fe3+ layer. Eventually, the PA layer was formed on the membrane surface through contacting with m-phenylenediamine aqueous solution and trimesoyl chloride/n-hexane solution consecutively. Significant FindingsThe TFC membrane exhibited extraordinary dyes rejection and good methanol permeance in OSN applications. Moreover, DMF activation process was conducted on the TFC membrane, after which both the dye rejection performance and methanol permeance were enhanced. Moreover, it is worth pointing out that the membrane provided an excellent solvent stability after dipping in DMF after 100 days.

The effects of nanoclay and carbon nanotube co‐addition on properties of an amorphous polyamide/maleated styrene‐ethylene‐co‐butylene‐styrene blend

AbstractThis work studied the individual and combined addition of natural (MMT‐Na) and modified (MMT‐30B) nanoclays, and carbon nanotubes (CNTs) to a poly (hexamethylene isophthalamide co‐terephthalamide) (aPA)/styrene‐ethylene/butylene‐styrene (SEBS) blend grafted with maleic anhydride. Their effects on the blend's morphology, thermo‐mechanical properties, and flammability were evaluated. Morphological analysis showed that both clays were located in the aPA matrix, with the MMT‐Na as agglomerates and the MMT‐30B intercalated with exfoliated regions. The CNTs were dispersed and randomly oriented in the aPA matrix. Data obtained through dynamic‐mechanical analysis (DMA) showed that adding 1.0% MMT‐30B and 1.0% CNT increased the storage modulus (E') by 26% and 27%, respectively, while adding both 0.5% MMT‐30B and 0.5% CNT increased E' by 38%, suggesting synergy between the nanoparticles related to mechanical properties. Regarding flammability, since the first burn timing (t1) could not be obtained, none of the samples could be classified according to the UL94 standard. However, qualitatively, a better flammability performance was noticed for the nanocomposites than for the pure blend.

Characterization and modeling of a thermoplastic elastomer tissue simulant under uniaxial compression loading for a wide range of strain rates

Characterization and modeling of the mechanical behavior of biological tissues are critical to many biomedical related applications. For research and development, various soft materials have often been used as a tissue substitute. Among them, the mineral oil-based synthetic polymer styrene-ethylene-butylene-styrene (SEBS) gel has gained some popularity due to its superior mechanical and physical properties. Tissue materials or their simulants are often characterized with quasi-static loading and are treated and modeled as a nonlinear hyperelastic material. As tissues are often subjected to loadings with a wide range of strain rates, understanding of the mechanical behavior and development a predictive capability for such loadings are essential. In this work, a comprehensive study of the mechanical behavior of SEBS gels with different chemical compositions and polymer concentrations was conducted under uniaxial compression loadings over a wide range of strain rates, from 1×10−3/s to 6×103/s. In addition to experiments, a comprehensive but simple visco-pseudo-hyperelasticity model was developed. The model was demonstrated to be able to capture all the material features observed in the experiments, such as rate sensitivity, strain-induced softening, and permanent deformation after unloading. Because of its simple functional form, the model can be conveniently used for practical applications such as prediction of the rate dependence of the shear modulus.

Sulfonated Block Ionomers Enable Transparent, Fire-Resistant, Tough yet Strong Polycarbonate

• Multifunctional ionomer (sSEBS-Ce) is rationally designed and synthesized. • 1.5 wt% of sSEBS-Ce obviously increases the fire resistance and toughness of PC. • The tensile strength and transparency of PC/sSEBS-Ce are well-preserved. • Structure-composition-property correlation of sSEBS-Ce in PC is revealed. Polycarbonate (PC) features high transparency and balanced mechanical properties, and thus is being growingly used for producing many high-end products, e.g. , construction facades, sensors and 5G equipment. For these applications, PC is required to combine satisfactory fire retardancy and great toughness while retain its mechanical strength and optical transparency. However, existing either fire retardants or toughening agents fail to enable PC to achieve such a required performance portfolio due to their improper molecular designs. To overcome this challenge, we, herein, rationally design a series of sulfonated ionomeric fire retardants (sSEBS-M, M = Na + , Zn 2+ , Ce 3+ ) by sulfonating and neutralizing styrene-ethylene-butylene-styrene (SEBS). The sSEBS-M can be well-dispersed within the PC matrix with phase domain sizes less than 500 nm. Chemical structures of sSEBS-M and their dispersion within the polymer matrix strongly correlate to their comprehensive performances in PC. Among three sSEBS-M ionomers, sSEBS-Ce endows PC with better comprehensive performances. With 1.5 wt% of sSEBS-Ce, the final PC achieves a high limiting oxygen index of 33.5% and a desired UL-94 V-0 rating, in addition to a 53% reduction in peak heat release rate and a comparable transparency to virgin PC. Moreover, its impact toughness and ductility are enhanced by 40% and 116% with tensile strength well-preserved. The integrated performance portfolios are superior to previous counterparts. This work offers a novel strategy for the design of multifunctional ionomer-based fire retardants for creating high-performance PC and reveals its structure-composition-property relationship in PC, which will enable PC to realize its practical applications in above-mentioned industries.

Stretchable, Breathable, and Stable Lead-Free Perovskite/Polymer Nanofiber Composite for Hybrid Triboelectric and Piezoelectric Energy Harvesting.

Halide-perovskite-based mechanical energy harvesters display excellent electrical output due to their unique ferroelectricity and dielectricity. However, their high toxicity and moisture sensitivity impede their practical applications. Herein, a stretchable, breathable, and stable nanofiber composite (LPPS-NFC) is fabricated through electrospinning of lead-free perovskite/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and styrene-ethylene-butylene-styrene (SEBS). The Cs3 Bi2 Br9 perovskites serve as efficient electron acceptors and local nucleating agents for the crystallization of polymer chains, thereby enhancing the electron-trapping capacity and polar crystalline phase in LPPS-NFC. The excellent energy level matching between Cs3 Bi2 Br9 and PVDF-HFP boosts the electron transfer efficiency and reduces the charge loss, thereby promoting the electron-trapping process. Consequently, this LPPS-NFC-based energy harvester displays an excellent electrical output (400V, 1.63 µA cm-2 , and 2.34 W m-2 ), setting a record of the output voltage among halide-perovskite-based nanogenerators. The LPPS-NFC also exhibits excellent stretchability, waterproofness, and breathability, enabling the fabrication of robust wearable devices that convert mechanical energy from different biomechanical motions into electrical power to drive common electronic devices. The LPPS-NFC-based energy harvesters also endure extreme mechanical deformations (washing, folding, and crumpling) without performance degradation, and maintain stable electrical output up to 5 months, demonstrating their promising potential for use as smart textiles and wearable power sources.

Modified cork/SEBS composites for 3D printed elastomers

AbstractThree dimensional (3D) printed elastomers is a challenge which can be overcome using fillers. With that in perspective, cork was chemically modified via a two‐step reaction, aiming to achieve better compatibility with styrene‐ethylene‐butylene‐styrene (SEBS). In the first step, the OH groups of cork surface were grafted with succinic acid, while in the second step the free acid groups were reacted with a polyol to produce ester moieties. Spectroscopy analysis confirmed the occurrence of the chemical reaction which was supported by contact angle (CA) measurements. The unmodified cork presents a CA of 117.7°, while the modified cork presents a CA of 92.4° which is closer to that of SEBS (102.8°), resulting in better compatibility between the modified filler with the matrix. In fact, the enhancement of compatibility between polymer and filler was observed by inspecting the layer‐to‐layer bonding and was confirmed by the mechanical properties of the 3D printed composites, since the modified cork‐based composite presented higher Young modulus, maximum stress and elongation at break when compared to the untreated counterparts. Additionally, the advantage of the chemical treatment was evaluated by analyzing the processability of composites. The modified filler‐based composite, presents lower glass transition temperature (Tg), higher melt flow index (MFI) and higher thermal stability. Overall, in this work, a simple chemical route to modify lignocellulosic biomass and its benefit on the properties of 3D printing objects is discussed. The improved performance and sustainability of the 3D printed objects produced to be used for example in shoe applications was presented.

SEBS-Polymer-Modified Slag–Cement–Bentonite for Resilient Slurry Walls

In spite of the well-established design and construction approaches of slag–cement–bentonite slurry walls, the materials deteriorate inevitably in contaminated land. The development of effective materials which are sustainable, resilient and self-healing over the lifetime of slurry walls becomes essential. This study, for the first time, adopts a styrene–ethylene/butylene–styrene (SEBS) polymer to modify slag–cement–bentonite materials to enhance mechanical and self-healing performance. The results show that the increase in SEBS dosage results in significantly increased strain at failure, indicating the enhanced ductility thanks to the modification by the deformable polymer. The increased ductility is beneficial as the slurry wall could deform to a greater extent without cracks. After the permeation of liquid paraffin, the SEBS exposed on the crack surface swells and seals the crack, with the post-healing permeability only slightly higher than the undamaged values, which exhibits good self-healing performance. Scanning electron microscopy and micro-computed tomography analyses innovatively reveal the good bonding and homogeneous distribution of SEBS in slag–cement–bentonite. SEBS acts as a binder to protect the slag–cement–bentonite sample from disintegration, and the swollen SEBS particles effectively seal and heal the cracks. These results demonstrate that the SEBS-modified slag–cement–bentonite could provide slurry walls with resilient mechanical properties and enhanced self-healing performance.

Corrosion resistance of a superelastic NiTi alloy coated with graphene–based coatings

The mechanical responses under superelastic loading cycles and the corrosion protection capacity of two graphene–based coatings applied to a NiTi alloy were evaluated. Graphene oxide (GO) and a composite of reduced graphene oxide (rGO) incorporated in a block copolymer of styrene–ethylene–butylene–styrene (SEBS) were deposited on the substrate via dip–coating. The morphology of the coatings was characterized by scanning electron microscopy (SEM) before and after uniaxial loading cycles up to 6%. Atomic force microscopy (AFM) was also used to evaluate the roughness of the coatings, which was expressed in terms of average roughness (Ra). The corrosion behavior was studied by potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), and Mott–Schottky analysis (MSA). SEM images suggested that both GO and rGO + SEBS create uniform coatings on the substrate. The measured Ra was 25 ± 3 nm for the bare NiTi, 24 ± 3 nm for the GO coated NiTi, and 8 ± 2 nm for the rGO + SEBS coated NiTi. Both coatings presented the capacity of following several superelastic cycles, maintaining their morphological integrity. PP and EIS showed that only the rGO + SEBS coating results in a significant improvement in terms of corrosion resistance. Furthermore, rGO + SEBS decreased the oxygen vacancies in the passive film when compared with the bare NiTi and GO coating.

Evaluation of rheological and aging behavior of modified asphalt based on activation energy of viscous flow

Styrene–butadiene–styrene (SBS) is one of the most widely used polymer modifiers for the improvement of the durability of asphalt pavement. SBS functionalization can improve the low-and high-temperature performance and aging resistance of asphalt binders. This paper systematically explores the feasibility of the activation energy of viscous flow (Ea) in evaluating the rheological and aging behavior of functionalized SBS-modified asphalt binders, including SBS-, styrene–ethylene/butylene–styrene (SEBS)-, SEBS-grafted maleic anhydride (MAH)-, and SBS/organic montmorillonite (OMMT) nanocomposites- modified asphalts (SBS-A, SEBS-A, MAH-A, and OSBS-A for short). The Ea values of different functionalized materials were calculated by Arrhenius equation based on Dynamic Shear Rheometer (DSR) and Rotational Viscosimeter (RV) tests, which means that the viscous flow behavior were analyzed at different temperature ranges. Ea based on RV test, the rutting factor and rutting factor aging index came to the same conclusion, that is, SEBS-A and OSBS-A with higher Ea values (lower temperature sensitivity) show excellent rheological properties and better aging resistance, followed by SBS-A, MAH-A, and base asphalt (BA). Besides, Ea based on DSR test was higher than Ea based on RV test, which is related to physical phase (visco-elastic phase and viscous phase). From the perspective of the viscous flow behavior of the binders, Ea based on RV test provides scientific and effective methods for probing the effect of SBS functionalization and designing high capability materials for pavement.

TFC solvent-resistant nanofiltration membrane prepared via a gyroid-like PE support coated with polydopamine/Tannic acid-Fe(III)

Solvent resistant nanofiltration (SRNF) is now a powerful tool for addressing environmental issues. Hence, we report the fabrication of a thin film composite (TFC) membrane comprised of a novel HDPE support, a polydopamine (PDA)/Tannic acid-Fe(III) interlayer and a polyamide (PA) skin layer. In this respect, high density polyethylene (HDPE)-polystyrene (PS)-styrene-ethylene-butylene-styrene (SEBS) blends were formed with different compositions by mixing via a Brabender machine and making films by using a hot press instrument. Next, a solvent extraction technique was employed for extracting the dispersed phase and making the HDPE membranes. The support membrane with optimum properties was coated with a PDA interlayer. A tannic acid-Fe(III) interlayer was also formed on the as-prepared PDA layer so that the hydrophilicity of the support surface was enhanced to form a defect-free PA layer. The modified support was utilized for the fabrication of the PA top layer by using m-phenylene diamine (MPD) and trimesoyl chloride (TMC) monomers. The prepared TFC membrane provided a significant dye rejection ability (99.9% Direct Yellow, 99.7% Methyl Green, 99.2% Rhodamine B, and 96.1% Methyl Orange), extraordinary solvent resistance ability in harsh solvents, and good methanol (MeOH) Flux (2.25 L/m2.h.bar) in SRNF applications. The skin-substrate adhesion strength of the top layer was also evaluated by a back-ward flush operation. It was demonstrated that the interlayer and the skin layer had an excellent adhesion with the support membrane.

Enhanced mechanical properties of recycled blends acrylonitrile–butadiene–styrene/high–impact polystyrene from waste electrical and electronic equipment using compatibilizers and virgin polymers

AbstractWaste electrical and electronic equipment (WEEE) are currently constituted by a considerable fraction of polymers, mainly acrylonitrile–butadiene–styrene (ABS) and high‐impact polystyrene (HIPS). Despite the increasing interest for ABS and HIPS recycling from WEEE, some factors, such as intrinsic mixture between polymeric components, are barriers to the advancement of the polymeric WEEE recycling. In present study, ABS and HIPS from WEEE were combined each other and with virgin ABS and HIPS in presence of the compatibilizers styrene–butadiene–styrene (SBS) and styrene–ethylene–butylene–styrene/styrene–ethylene–butylene (SEBS/SEB), generating recycled ABS/HIPS blends in different compositions. The materials were evaluated by mechanical tests, morphological analysis, dynamic‐mechanical‐analysis, and melt flow rate. The presence of compatibilizers SBS and SEBS/SEB affects significantly the morphological structure of ABS/HIPS, changing the shape and size of the dispersed phases of styrene–acrylonitrile or polystyrene, which leads to modifications of the mechanical properties of the materials. The presence of virgin polymer in the blends also affects the material morphology. Thus, ABS and HIPS waste from WEEE can be recycled as ABS/HIPS blends and their mechanical properties controlled by use of compatibilizers SBS and SEBS/SEB and incorporation of virgin polymers, avoiding processes for segregation of the polymers during mechanical recycling.

SEBS as an Effective Nucleating Agent for Polystyrene Foams.

Different percentages of an elastomeric phase of styrene-ethylene-butylene-styrene (SEBS) were added to a polystyrene (PS) matrix to evaluate its nucleating effect in PS foams. It has been demonstrated that a minimum quantity of SEBS produces a high nucleation effect on the cellular materials that are produced. In particular, the results show that by adding 2% of SEBS, it is possible to reduce the cell size by 10 times while maintaining the density and open cell content of the foamed materials. The influence of this polymeric phase on the glass transition temperature (Tg) and the shear and extensional rheological properties has been studied to understand the foaming behavior. The results indicate a slight increase in the Tg and a decrease of the shear viscosity, extensional viscosity, and strain hardening coefficient as the percentage of SEBS increases. Consequently, an increase in the density and a deterioration of the cellular structure is detected for SEBS amounts higher than 3%.

316L FFF binder development and debinding optimization

Fused Filament Fabrication (FFF) technology is used to create metal parts in this paper. A binder formula is developed for 316L stainless steel powder, composed of polypropylene (PP), styrene ethylene butylene styrene (SEBS) and paraffin wax (PW). The binder is mixed with the 316L stainless steel powder to produce mixture which is then extruded into filament. The optimum binder formula, PP:SEBS:PW = 5:2:2, is obtained by orthogonal experiment. After optimization, mixture viscosity is reduced, filament tensile strength is guaranteed, rigidity is improved. The filament can be printed by a desktop FFF printer to obtain green parts. Binder within the green parts can be sufficiently removed by solvent and thermal debinding, and the shape of printed parts can be maintained well. After sintering, shrunken 316L stainless steel parts can be created, some pores distributed inside. With finer metal powder, the relative density of sintered part can be increased to 96%. The research ideas of this paper can provide effective methods for the development and optimization of binder.

Printable dielectric elastomers of high electromechanical properties based on SEBS ink incorporated with polyphenols modified dielectric particles

In this work, a recently developed 3D additive processing technology termed electrohydrodynamic (EHD) printing was employed to fabricate dielectric elastomer (DE) films by using styrene-ethylene-butylene-styrene (SEBS) inks with the addition of high dielectric titanium dioxide (TiO2) nanoparticles. In order to improve the dispersibility of TiO2 in the SEBS matrix, extracted walnut polyphenols were utilized for surface modification of TiO2 nanoparticles labelled wp-TiO2. The effect of the applied voltage on the ink jet morphology of the obtained SEBS based inks during EHD printing was analyzed. The prepared films had precision patterned shapes and their morphology was studied. It revealed that the dispersibility of TiO2 nanoparticles in the SEBS matrix and their compatibility were greatly improved using this procedure. Furthermore, the printed DE films were found to have excellent mechanical, dielectric and electromechanical properties. For the range of DEs fabricated, the SEBS/10%wp-TiO2 composite exhibited the maximum actuated area strain of 21.5% at an electric field of about 34.0 V/μm without degradation of other properties.

Styrene‐Ethylene/Butylene‐Styrene (SEBS) Block Copolymer Binder for Solid Propellants

AbstractCurrently solid composite propellants are manufactured using bespoke, specially manufactured binders. This adds significant cost and obsolescence risks to their development and manufacture. This paper reports on the production of two composite propellants made from a commercially‐available‐off‐the‐self polymer as binder by means of a resonant acoustic mixer (RAM) slurry process. The binder consisted of thermoplastic elastomer styrene‐ethylene/butylene‐styrene (SEBS) block copolymer and the solid filler, either ammonium perchlorate (AP) or 1,3,5‐Trinitro‐1,3,5‐triazinane (RDX). Thermodynamic code demonstrated that SEBS‐based propellants exhibited similar theoretical ballistic performance to conventional HTPB‐based propellants. Chemical compatibility between SEBS and the solid fillers was shown by the differential scanning calorimetry (DSC) and vacuum stability methods. The novel combination of RAM and slurry coating process produced a propellant moulding powder that was then consolidated by remote hot pressing to simulate an industrial extrusion or rolling process. The propellants exhibited as expected explosive hazard properties and their thermal analysis by DSC‐TGA showed typical oxidizer behaviour between AP and SEBS, characterised by two decomposition exotherms (also reported in AP/HTPB compositions), and little or no interaction between RDX and SEBS. The apparent activation energy for decomposition for AP/SEBS (84/16 % w/w) propellant was similar to that for AP/HTPB propellants. This work demonstrates the viability of using SEBS polymer as a binder for solid propellants. The development of propellants using commercially off the shelf, thermoplastic elastomeric binders could add significant benefits in waste reduction through recycling, security of supply, and manufacturing costs.

Glycerol-in-SEBS gel as a material to manufacture stable wall-less vascular phantom for ultrasound and photoacoustic imaging

Styrene-ethylene/butylene-styrene (SEBS) copolymer-in-mineral oil gel is an appropriate tissue-mimicking material to manufacture stable phantoms for ultrasound and photoacoustic imaging. Glycerol dispersion has been proposed to further tune the acoustic properties and to incorporate hydrophilic additives into SEBS gel. However, this type of material has not been investigated to produce wall-less vascular flow phantom for these imaging modalities. In this paper, the development of a wall-less vascular phantom for ultrasound and photoacoustic imaging is reported. Mixtures of glycerol/TiO2-in-SEBS gel samples were manufactured at different proportions of glycerol (10%, 15%, and 20%) and TiO2 (0% to 0.5%) to characterize their optical and acoustic properties. Optical absorption in the 500–950 nm range was independent of the amount of glycerol and TiO2, while optical scattering increased linearly with the concentration of TiO2. Acoustic attenuation and speed of sound were not influenced by the presence of TiO2. The sample manufactured using weight percentages of 10% SEBS, 15% glycerol, and 0.2% TiO2 was selected to make the vascular phantom. The phantom proved to be stable during the pulsatile blood-mimicking fluid (BMF) flow, without any observed damage to its structure or leaks. Ultrasound color Doppler images showed a typical laminar flow, while the B-mode images showed a homogeneous speckled pattern due to the presence of the glycerol droplets in the gel. The photoacoustic images of the phantom showed a well-defined signal coming from the surface of the phantom and from the vessels where BMF was flowing. The Spearman’s correlations between the photoacoustic and tabulated spectra calculated from the regions containing BMF, in this case a mixture of salt solutions (NiCl2 and CuSO4), were higher than 0.95. Our results demonstrated that glycerol-in-SEBS gel was an adequate material to make a stable vascular flow phantom for ultrasound photoacoustic imaging.

Production and characterization of thermoplastic elastomer foams based on the styrene–ethylene–butylene–styrene (SEBS) rubber and thermoplastic material

Abstract Thermoplastic elastomer foams based on styrene–ethylene–butylene–styrene (SEBS)/polypropylene (PP) were produced by using different processing techniques such as extrusion and injection molding to achieve optimized mechanical and thermal properties in terms of strength, elongation, and damping capability. Foaming is a method of introducing gas-filled cells into the material and it is considered an effective way to meet the requirements for higher impact resistance with low density and relatively low hardness. In this study, microspheres were used as a foaming agent and were introduced to the system by using an injection molding machine. They were used in different percentages and ranged from 1 and 3%. They decrease the density of the product thereby lowering the weight and cost. Besides improving damping abilities and decreasing the density, inorganic fillers such as talc, silica, and calcium carbonate were used to increase the mechanical strength, and their effectivity was also investigated. It was observed that a higher amount of foaming agent lowered the density by creating voids in the blend, as expected. The introduction of fillers increases the mechanical properties; however, the density had a negative effect even in the presence of foaming agents. About 3% density reduction can be achieved in the presence of talc and a foaming agent whereas the other fillers had an opposite effect on the density. Accordingly, the impact resistance was affected negatively because of the stiffness of the filler materials, and the highest Izod impact value was 50.2 kJ/m2. The elastic modulus values for foamed samples and filled with CaCO3, talc, and silica were 808, 681, and 552 MPa respectively. Combining foaming and thermoplastic elastomers (TPEs) offers a wide variety of possibilities to new and existing applications. In addition to low hardness and density, foaming provides better damping ability thanks to its morphological structure.