Styrene Ethylene Research Articles

SEBS effect on 60Co radiation resistance behavior of PP/HDPE matrix for medical device applications

Radiation resistant polypropylene (PP) has become more and more critical in the medical industry. Composites of PP were synthesized by melting process in the presence of high-density polyethylene (HDPE) and styrene–ethylene–butylene–styrene triblock copolymer (SEBS). Under 60Co γ-ray irradiation, all samples were characterized by mechanical properties, thermal analysis, contact angle (CA), FT-IR analysis, and SEM. Under a 20 kG y dose irradiation, mechanical properties results show that the impact strength rose from 3.28 kJ/m2 to 4.40 kJ/m2, and the tensile strength decreased by 3.52 MPa. At the same time, CA's results show that a much higher irradiation dose makes CA lower, but the higher content of SEBS, the higher CA. To confirm the presence of polar oxygen-containing groups, the FT-IR was used, and the results show that the characteristic peak intensity of carbonyl groups decreased gradually. SEM images indicate that the number of cracks and plastic particles reduced gradually, and the radiation resistance of samples enhanced by the aromatic ring structure of SEBS.

Theoretical Studies of Reaction Mechanisms for Half-Titanocene-Catalyzed Styrene Polymerization, Ethylene Polymerization, and Styrene–Ethylene Copolymerization: Roles of the Neutral Ti(III) and the Cationic Ti(IV) Species

Reaction mechanisms of styrene polymerization, ethylene polymerization, and styrene–ethylene copolymerization catalyzed by the half-titanocene [(Me5C5)TiCl2(OAr)] complex were studied based on dens...

Investigation of the dynamics of the various relaxation processes in SEBS block copolymer possessing low styrene fraction

We constructed entire master curve exhibiting all probable relaxation processes in styrene ethylene butylene styrene, SEBS, block copolymer from isothermal shear compliance measurements. Measurements have been performed in steps depending on the velocity of the process investigated in the temperature region −60 to 160 °C. The frequency domain used is from 0.03 to 30 Hz. We applied the principle of time–temperature superposition, while taking in consideration the mismatch between activation responses of the two phases as a function of temperature. The styrene content in the sample is 13% by weight imposing another difficulty in investigating the polystyrene component. The resultant master curve was resolved into the contributing relaxation processes. The dynamics of the ethylene butylene, EB, and polystyrene, PS, relaxation processes are treated in the frame of the meander model of polymers in comparison to those observed in particular homopolymers.

A shapeable, ultra-stretchable rubber strain sensor based on carbon nanotubes and Ag flakes via melt-mixing process.

Promoting the detection range, durability, and shapeable manufacturing of flexible strain sensors is essential to broaden their applications. Therefore, in this study, styrene ethylene butylene styrene (SEBS) rubber as a flexible material and a melt-mixing molding method are adopted to design an ultra-flexible strain sensor. Carbon nanotubes (CNTs) are added to form a conductive network, and the effect of Ag flakes on improving the sensor performance is studied. The experiment results exhibit good strain-resistance dependent characteristics of the obtained sensor, which demonstrates an excellent sensing range of about 540% with a gauge factor (GF) of 5.197. The good hydrophobicity (water contact angle ≈120.4°), repeatable characteristics at different rates, strain-dependence and long-term recycling of the sensor are demonstrated as well. Finally, the fabricated round bracelet sensor is applied to detect different cross-sections, the movement of human joints, balloon inflation, bottle cap sealing and numerous other aspects.

Bagasse Fiber Reinforced Functionalized Styrene Ethylene Butylene Styrene Composites by Palsule Process

ABSTRACT Eco-friendly Bagasse Fiber Reinforced Functionalized Styrene Ethylene Butylene Styrene (BGF/CF-SEBS) composites have been developed by Palsule process by twin screw extrusion and injection molding. The composites show higher mechanical properties relative to the matrix that increases with increasing fiber contents in them. FE-SEM micrographs show good interfacial adhesion between reinforcing BGF and CF-SEBS matrix in the composites and FTIR confirms its origin from the ester and hydrogen bonds formed between –OH of BGF and anhydride of CF-SEBS in the composites. Thermal stability of the composites is intermediate between those of BGF and CF-SEBS.

Synthesis of C60-Coated Ferric Oxide and Its Application in Detecting Magnetic Field

Dispersibility and magnetic response characteristics of magnetic nanoparticles is crucial to the sensitivity and stability of flexible magnetic field sensors. To improve the performance of magnetic nanoparticles, this paper reported a preparation method of the fullerene-coated ferric oxide (C60@Fe3O4) magnetic nanocomposites. The TEM results showed that the C60@Fe3O4 has uniform dispersion and consistent particle size, and C60 particles are distributed on the surface of Fe3O4, forming a coating structure. The X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersion spectroscopy results further proved that the compositions of the nanomaterials are Fe3O4 and C60. The VSM hysteresis loop of the nanocomposites showed good performance in magnetic response. Then, styrene ethylene butylene Styrene (SEBS), the C60@Fe3O4 magnetic nanoparticles, and CNTs, which were used as flexible substrate, magnetic sensitive unit, and conductive networks, respectively, composed the flexible magnetic field sensor. The measurement results of the flexible magnetic field sensor showed its high sensitivity (2.1 T−1) and good stability. The mechanism of the sensor was explored at last.

Valorization of Biomass Gasification Char as Filler in Polymers and Comparison with Carbon Black

Char, the solid residue produced during biomass gasification, is usually treated as a waste with high environmental and economic costs associated to its disposal. However, char shows remarkable properties that make it suitable for a plethora of different applications. In particular, this study aims at investigating the feasibility of using char as filler in polymers for boosting polymer thermal stability and electrical conductivity, and comparing its performances with carbon black (CB), a more traditional carbonaceous filler. Char residues were collected from a commercial biomass gasifier, thoroughly characterized, and compared with CB. Both materials were used in combination with a styrene–ethylene–butylene–styrene (SEBS) matrix for the production of two different compounds, deeply characterized as well. An addition of 44 wt% of char increases the thermal stability of the compound and its electrical conductivity up to 2 × 10−3 S cm−1, without interfering with its structure and mechanical properties. Less CB (20 wt%) was needed for obtaining composites with the same electrical conductivity. The findings of this study pave the way for new valorization routes for large amounts of char in cutting-edge applications and present the opportunity to the polymer manufacturing to use a high-available and low-cost substitute for carbon-based fillers.

Effects of Porosity and SEBS Fraction on Dry Sliding Friction of EVA Foams for Sports Shoe Sole Applications

Ethylene vinyl acetate (EVA) foam is sometimes used in the outer soles of sport shoes. To improve the slip resistance of EVA foam, this study investigated the effects of porosity and the fraction of styrene–ethylene–butadiene–styrene (SEBS) on the dry sliding friction behavior of EVA foams. Sliding friction tests were performed against a pin specimen with a semicylindrical tip, which was covered with (rough surface) or without abrasive paper (smooth surface). The results revealed that the friction coefficient of the EVA foam increased with porosity when slid against a smooth surface, whereas its friction coefficient increased with porosity and SEBS fraction when slid against a rough surface. The results of this investigation provide insight into how to increase the dry sliding friction of resin foam against smooth and rough surfaces, which will also contribute to improving the slip resistance of shoe soles made from resin foam.

The influence of cohesion and adhesion parameters on the moisture sensitivity of modified Asphalt mixtures with polymer additive

ABSTRACT Moisture sensitivity is one of the common distresses in flexible pavements due to the deteriorating effect of water on adhesion of bitumen-aggregate and cohesion of mastic. In the present study, the effect of the styrene–ethylene–butylene–styrene as bitumen modifier was examined on the moisture damage potential of control and modified asphalt mixtures using thermodynamic and mechanical methods. The results of this study indicated that the modified asphalt mixtures have significantly better resistance than the control samples. In addition, the results of the thermodynamic parameters showed that changes in the surface-free energy components of the modified bitumen have improved the adhesion of these bitumens to high silica aggregates that are susceptible to moisture. Moreover, the use of styrene–ethylene–butylene–styrene increases the surface-free energy of mastic film, which also increases the resistance to cohesion failure. Furthermore, the results of the amount of energy released during the stripping event show that the use of bitumen modifying polymer additive has reduced the amount of de-bonding energy. This indicates that the tendency for bitumen to detach from the aggregate surface in the presence of water has decreased from the thermodynamics view.

SEBS-b-TPU and nanoclay: effective compatibilizers for promotion of the interfacial adhesion and properties of immiscible SEBS/TPU blends

High-performance polystyrene-b-poly (ethylene-butylene)-b-polystyrene/thermoplastic polyurethane (SEBS/TPU) blends containing polyurethane blocked styrene–ethylene–butylene–styrene (SEBS-b-TPU) and SEBS-b-TPU/clay were obtained by melt mixing. The influence of SEBS-b-TPU and nanoclay content on morphology, mechanical, thermal, rheological and abrasion behavior of the SEBS/TPU blends were investigated. SEM results indicated that the domain size of the TPU phase was remarkably reduced by the presence of SEBS-b-TPU. Moreover, the addition of clay further improved the extent of mixing. TEM and SEM–EDX revealed that nanoclays were preferentially located in and along the outer edge of the TPU phase with an intercalated/exfoliated structure. TGA results showed that the degradation temperatures (T5%) were increased by 12.3 °C and 20.8 °C for SEBS/TPU/SEBS-b-TPU-7% and SEBS/TPU/SEBS-b-TPU/clay-3% nanocomposites, respectively, compared with that of SEBS/TPU. There was also an improvement in mechanical and rheological properties as expected. Meanwhile, the abrasion resistance of SEBS/TPU blends was considerably enhanced by the presence of SEBS-b-TPU/clay, the DIN volume loss decreased by as much as 56%, which can be attributed to the dispersion of the clay platelets in nanoscales as well as the enhanced interfacial adhesion. These superior properties of the SEBS/TPU blends are important for many applications.

Rheology and foaming behaviour of styrene–ethylene–butylene–styrene nanocomposites

The dependence of the foaming behaviour of a polymeric material on its material characteristics and foaming temperature gives rise to the research question that how the degree of dispersion/distribution of nanoparticles and the resulting viscosity changes affect the foaming behaviour and properties of nanocomposite foams. In the study reported here, styrene–ethylene–butylene–styrene was selected as a model polymer, because of its complex microstructure and its commercial importance. Styrene–ethylene–butylene–styrene nanocomposites, with different nanoclay loadings, were processed in a twin-screw extruder. The nanocomposite structure was correlated with the rheological properties to evaluate the batch-foaming performance of nanocomposite using carbon dioxide at different temperatures. At 35 °C, selective foaming of the elastomeric phase, hindered by the stiff polystyrene phase, resulted in foams with more than 74% shrinkage. At 80 °C, higher viscosities and moduli resulted in foams with higher volume expansion ratios. Increases in the degree of delamination of silicate layers in nanocomposites resulted in cell sizes up to 41% and 75% lower than that of neat polymer foams produced at 35 °C and 80 °C, respectively. Dynamic mechanical analysis results suggest heterogeneous nucleation and the presence of nanoclay in both phases. The study results show that the nanocomposite structure plays an important role in the production of thermoplastic elastomer foams of superior morphology and low shrinkage.

Highly porous, soft, and flexible vapor-phase polymerized polypyrrole–styrene–ethylene–butylene–styrene hybrid scaffold as ammonia and strain sensor

Herein, in situ vapor-phase polymerization (VPP) of pyrrole on an oxidant-impregnated styrene–ethylene–butylene–styrene (SEBS) matrix comprising a three-dimensional sugar particle assembly was used to produce a soft and porous polypyrrole (PPy)–SEBS hybrid scaffold. Characterization of the PPy–SEBS hybrid scaffold using field-effect scanning electron microscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and micro-computerized tomography confirmed the successful uniform and homogenous polymerization of PPy onto the SEBS matrix with a porous morphology. The performance of the hybrid scaffold of different pore sizes as an ammonia sensor under different temperature conditions was evaluated in terms of resistance change. The results showed that the PPy–SEBS scaffolds of larger pore size had higher resistance changes under lower temperature conditions when ammonia (NH3) gas was introduced compared to those observed for smaller pore sizes under higher temperature conditions. These scaffolds showed excellent repeatability and reversibility in detecting NH3 gas with fast response and recovery times of 30 s and 10–15 min, respectively. Moreover, the larger pore size scaffolds polymerized for a longer time possessed a remarkable ability to be applied as strain sensors. These kinds of novel, soft, and porous conductive polymer composite materials produced by VPP will have huge practical applications in monitoring other toxic and non-toxic gases.

Intrinsically stretchable all-carbon-nanotube transistors with styrene-ethylene-butylene-styrene as gate dielectrics integrated by photolithography-based process.

In recent years, stretchable electronics have attracted great attention because of their broad application prospects such as in the field of wearable electronics, skin-like electronics, medical transplantation and human–machine interaction. Intrinsically stretchable transistors have advantages in many aspects. However, integration of intrinsically stretchable layers to achieve stretchable transistors is still challenging. In this work, we combine the excellent electrical and mechanical properties of carbon nanotubes with excellent dielectric and mechanical properties of styrene–ethylene–butylene–styrene (SEBS) to realize intrinsically stretchable thin film transistors (TFTs). This is the first time that all the intrinsically stretchable components have been combined to realize multiple stretchable TFTs in a batch by photolithography-based process. In this process, a plasma resistant layer has been introduced to protect the SEBS dielectric from being damaged during the etching process so that the integration can be achieved. The highly stretchable transistors show a high carrier mobility of up to 10.45 cm2 V−1 s−1. The mobility maintains 2.01 cm2 V−1 s−1 even after the transistors are stretched by over 50% for more than 500 times. Moreover, the transistors have been scaled to channel length and width of 56 μm and 20 μm, respectively, which have a higher integration level. The stretchable transistors have light transmittance of up to 60% in the visible range. The proposed method provides an optional solution to large-scale integration for stretchable electronics.

Encapsulate Materials Effect on ZnxCd1-xS White Light Quantum Dots-Based White Light-Emitting Diodes

In this study, colloidal ternary ZnxCd1-xS white light quantum dots (WQDs) were prepared, which have the characteristics of broad emission window. We used epoxy, styrene ethylene butylene styrene block copolymer (SEBS), and silicone as encapsulate materials to pack the device. The results show that the Zn0.5 and Zn0.8 have band edge and surface state emission. The quantum yield (QY) and particle size of Zn0.5 and Zn0.8 WQDs is 19, 32 % and 4.5±0.5 and 3.1±0.5 nm, respectively. The white light-emitting diodes (WLEDs) were obtained by mixing WQDs with different resins, and pumping by UV chip. The luminous efficacy is 6.7 and 8.5 lm/W for Zn0.5 and Zn0.8-based WLED by using epoxy resin as encapsulate material. Moreover, the long period test can maintain 201 and 184 h for Zn0.5 and Zn0.8-based WLED, respectively. The results of this study present that the device encapsulated by epoxy resin can improve the luminous efficacy and stability of device. This outstanding finding may contribute to the future development of solid-state lighting (SSL).

Toughness improvement of novel biobased aromatic polyamide/SEBS/organoclay ternary hybrids

ABSTRACTBiobased aromatic polyamide/organoclay (Cloisite30B, C30B) nanocomposites were melt‐compounded with reactive and nonreactive styrene–ethylene–butylene–styrene (SEBS) rubbers at different weight contents to form ternary and quaternary blends. The mechanical properties were investigated as a function of the blend composition. The elongation at break and the impact strength increase with increasing SEBS rubber content, whereas the Young's modulus logically decreases proportionally to SEBS amount. Extra addition of SEBS grafted maleic anhydride (SEBS‐g‐MA) induces a synergistic effect. The SEBS‐g‐MA makes it possible to limit the aforementioned rigidity loss and to greatly increase the impact strength. The critical strain energy release rate increases significantly when both reactive and nonreactive rubbers are combined. Three types of microstructures appear depending on the blend composition: (1) small and numerous well‐dispersed particles when reactive rubber is used, (2) about 10 times bigger and less numerous well‐dispersed particles in the case of nonreactive rubber, and (3) a flocculated dispersion of small particles when both reactive and nonreactive rubber are added. Finally, the polyamide performances were significantly increased when the flocculated morphology was noticed due to a better PAXD/SEBS interfacial adhesion given by the SEBS‐g‐MA compatibilization and to a thinner rubber distribution in the matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48888.

Melt rheology and interfacial properties of binary and ternary blends of PS, EOC, and SEBS

ABSTRACTThis works systematically investigates the interfacial properties of the binary and the ternary blends based on polystyrene (PS), ethylene octene copolymer (EOC), and styrene–ethylene–butylene–styrene (SEBS) by analyzing the melt linear rheological behavior of the blends and neat components. Moreover, the relationship between rheology, phase morphology, and mechanical properties of PS/EOC ternary blends with various quantities of SEBS were studied. The surface shear modulus (β) and interfacial tension values obtained by Palierne model indicated that the EOC/SEBS blend has the best interfacial properties, while the lowest interaction was found for PS/EOC blend. Based on the Palierne model and Harkin's spreading coefficients a core–shell type morphology with EOC phase encapsulated by the SEBS shell dispersed in the PS matrix was determined for the ternary blends. Scanning electron microscopy results revealed that both fibrillar and droplet forms of dispersed phase could be developed during the blending of PS and EOC in presence of SEBS. The extent of fibrillar morphology and interfacial interactions in PS/EOC/SEBS ternary blends was dependent on the SEBS content. The improvement of the mechanical properties of PS/EOC blends in the presence of SEBS was evidenced by the tensile and impact resistance experiments. The tensile strength reinforcement was more pronounced for the ternary blends with more fibrillar dispersed phase. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48791.

Effect of sequence of melt mixing on the properties and morphology of blends of polypropylene, styrene–ethylene–butylene–styrene copolymer grafted with maleic anhydride, and organophilic montmorillonite clay

Styrene–ethylene–butylene–styrene (SEBS) copolymer, grafted or not, with maleic anhydride and organophilic montmorillonite clay was melt mixed with polypropylene (PP) using different mixing sequences to understand its effect on properties and morphology. The addition of clay changed the blend morphology from large elongated domains to droplets. The nanocomposites without maleic anhydride presented clay in the intercalated form. In the formulation containing maleic anhydride, clay is exfoliated on the blend, indicating that the maleic anhydride group acted to increase the interaction between the clay lamellae and the polymer chains. The best balance of mechanical properties was achieved in the formulation in which the clay was first melt mixed in SEBS without maleic anhydride and afterward melt mixed with clay and PP. It is reported in the literature that nanocomposites with exfoliated structures have better mechanical properties than nanocomposites with intercalated structure. However, in this study, an opposite trend was found, which may be related to the higher amount of crystalline phase formed in the intercalated structure nanocomposites, since the clay intercalation phenomenon in the polymer chains favored the polymer crystallization process.

Augmentation of performance properties of maleated SEBS/TPU blends through reactive blending

ABSTRACTMeticulous investigation of reactive blending of maleic anhydride grafted styrene–ethylene–butylene–styrene (SEBS‐g‐MA) and thermoplastic polyurethane (TPU) is carried out to achieve systems with controllable morphology and superior mechanical properties. Two types of SEBS‐g‐MA (abbreviated as M1, M2) with different maleic anhydride content were used to separately blend with TPU. Formation of imide group from the interaction of isocyanate and maleic anhydride predicted from the plausible reaction scheme was confirmed through Fourier transform infrared spectroscopy. High tensile strength of the blends along with appreciable elongation at break was witnessed. Morphology analyses using scanning electron microscopy and atomic force microscopy exposed a vivid and homogenous droplet morphology in all the blends presumably due to in situ formation of a suitable copolymer at the interface. Differential scanning calorimetry was used to pursue the thermal characteristics of the blends. Melt‐rheological behavior of the blends was examined using a rubber process analyzer. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48727.

Viologen/Bromide Dual-Redox Electrochemical Capacitor with Two-Electron Reduction of Viologen.

In this work, we report a novel dual-redox electrochemical capacitor (EC) using a modified viologen (V) as anolyte and bromide (Br) as catholyte. In general, modified viologens are dications. When they are used as anolyte in aqueous dual-redox ECs, only one-electron reduction reaction can occur, because most divalent and monovalent viologens are soluble but zerovalent viologens are insoluble. The insoluble and nonconductive zerovalent viologens will block the surface of the activated carbon electrode from subsequent reactions. The energy densities of the dual-redox ECs using viologens are expected to be greatly improved if those viologens can carry out multiple electron reduction reactions. In this work, 1,1'-bis[3-(trimethylammonio)propyl]-4,4'-bipyridinium (NV4+), a tetra-cationic viologen, has been used as anolyte for dual-redox EC. NV2+ produced by two-electron reduction of NV4+ is highly soluble in aqueous solution, so that two consecutive one-electron reductions of viologen can be utilized in dual-redox ECs. To further solve the cross-diffusion issue of the charging products, Br3- and NV cations, of the positive and the negative electrodes, we have used tetrapropyl ammonium cation (TPA+) to complex Br3-, and quaternized styrene ethylene butylene styrene (SEBS-QA) anion exchange membrane (M) to block the cross-diffusion of NV cation. The obtained NV/TPA/Br-M (NV4+/TPA+/Br- electrolyte with SEBS-QA membrane) dual-redox EC exhibits an average Coulombic efficiency over 99%. It also provides a high specific energy of 87 Wh/kgdry at 1 A/gdry and a peak power density of 4.8 kW/kgdry at 5 A/gdry. The functions of TPA+ and SEBS-QA membrane were characterized and are discussed in detail.

Development of blown film linear low‐density polyethylene–clay nanocomposites: Part A: Manufacturing process and morphology

ABSTRACTIn this study, linear low‐density polyethylene (LLDPE)/clay nanocomposites with different clay contents were prepared by melt intercalation using two different compatibilizers: maleic anhydride grafted styrene–ethylene–butylene–styrene and maleic anhydride grafted polyethylene (PE‐g‐MA). Melt intercalation was achieved by twin extrusion and nanocomposite films were produced by blown film extrusion. Effects of clay and compatibilizer fractions and type of compatibilizer on the structure, permeability, and the barrier properties of the nanocomposite films were investigated. PE‐g‐MA was shown to notably improve the dispersion of clay layers in the polyethylene matrix, and this was examined by atomic force microscopy and X‐ray diffraction. The latter tests have also highlighted the importance of the screw configuration: the presence of mixing elements favors the dispersion and distribution of nanoclay. Moreover, differential scanning calorimetry results have shown no significant effect of the clay on the crystallinity of the composite while thermogravimetric analysis tests have demonstrated a decrease of onset and peak of decomposition temperatures. Finally, barrier properties toward water vapor transmission were measured. It was proven that not also clay, but the compatibilizer participated in decreasing the permeability of the film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48589.