Styrenic Thermoplastic Elastomers Research Articles

Fundamental Principles and Emerging Opportunities for Selectively‐Solvated Block Copolymer Networks in Nonpolar Media: A Perspective

AbstractBlock polymers remain an extensively studied class of macromolecules due to their ability to self‐organize spontaneously as a result of microphase separation into a variety of ordered nanostructures, depending on the number of contiguous sequences (“blocks”) present and their sequential arrangement. These polymers are classified as multifunctional since they exhibit two or more different property sets during application. In this work, the focus is on bicomponent block copolymers composed of soft and hard segments arranged as linear triblock or higher‐order multiblock copolymers and possessing the properties of a thermoplastic elastomer (TPE). Of particular interest are selectively‐solvated TPEs, designated as TPE gels (TPEGs), with precisely‐ and composition‐tunable properties. An important aspect of TPEs and their TPEG analogs is their elasticity, which reflects the ability of the soft block(s) to form a contiguous molecular network connected by dispersed microdomains composed of the hard block. Here, the origins of microphase separation and network formation in styrenic TPEs and TPEGs are explored, and experimental, theoretical, and simulation results are examined to elucidate chemistry‐structure‐property‐processing (CSPP) relationships in these self‐networking materials. Once such relationships are established, several unconventional technologies that can directly benefit from TPEGs, along with TPEGs fabricated from TPEs possessing different chemical moieties, are likewise considered.

Development of Toughening Technology for Styrenic Thermoplastic Elastomers by Incorporating Non-Covalent Interactions

Development of Toughening Technology for Styrenic Thermoplastic Elastomers by Incorporating Non-Covalent Interactions

Nopadiene: A Pinene-Derived Cyclic Diene as a Styrene Substitute for Fully Biobased Thermoplastic Elastomers.

The bicyclic 1,2-substituted, 1,3-diene monomer nopadiene (1R,5S)-2-ethenyl-6,6-dimethylbicyclo[3.1.1]hept-2-ene was successfully polymerized by anionic and catalytic polymerization. Nopadiene is produced either through a facile one-step synthesis from myrtenal via Wittig-olefination or via a scalable two-step reaction from nopol (10-hydroxymethylene-2-pinene). Both terpenoids originate from the renewable β-pinene. The living anionic polymerization of nopadiene in apolar and polar solvents at 25 °C using organolithium initiators resulted in homopolymers with well-controlled molar masses in the range of 5.6-103.4 kg·mol-1 (SEC, PS calibration) and low dispersities (Đ) between 1.06 and 1.18. By means of catalytic polymerization with Me4CpSi(Me)2NtBuTiCl2 and (Flu)(Pyr)CH2Lu(CH2TMS)2(THF), the 1,4 and 3,4- microstructures of nopadiene are accessible in excellent selectivity. In pronounced contrast to other 1,3-dienes, the rigid polymers of the sterically demanding nopadiene showed an elevated glass temperature, Tg,∞ = 160 °C (in the limit of very high molar mass, Mn). ABA triblock copolymers with a central polymyrcene block and myrcene content of 60-75 mol %, with molar masses of 100-200 kg/mol were prepared by living anionic polymerization of the pinene-derivable monomers nopadiene and myrcene. This diene copolymerization resulted in thermoplastic elastomers displaying nanophase separation at different molar ratios (DSC, SAXS) and an upper service temperature about 30 K higher than that for traditional petroleum-derived styrenic thermoplastic elastomers due to the high glass temperature of polynopadiene. The materials showed good thermal stability at elevated temperatures under nitrogen (TGA), promising tensile strength and ultimate elongation of up to 1600%.

Core-shell structure antioxidant microencapsulated piperazine pyrophosphate towards improving service performance and fire safety of styrenic thermoplastic elastomer

Core-shell structure antioxidant microencapsulated piperazine pyrophosphate towards improving service performance and fire safety of styrenic thermoplastic elastomer

Synergistic effects of core-shell structured piperazine pyrophosphate microcapsules on fire safety and mechanical property in styrenic thermoplastic elastomer

In this study, core-shell structured piperazine pyrophosphate (PAPP) is designed to enhance the fire safety and mechanical property of styrenic thermoplastic elastomer (TPE) composites. The PAPP is microencapsulated with carbon nanotube modified melamine-formaldehyde resin to prepare core-shell structured flame retardants (MT@PAPP). Due to the excellent compatibility between the MT@PAPP and TPE matrix, the mechanical property of TPE/MT@PAPP is improved. Compared with TPE, the peak heat release rate and peak smoke production rate of TPE/MT@PAPP are decreased by 78.5% and 60.0%, respectively. Thus, the core-shell structured piperazine pyrophosphate microcapsule strategy provides an excellent approach to obtain high-performance TPE composites.

Structure and properties of blends based on vulcanized rubber waste and styrene–butadiene–styrene thermoplastic elastomer

Structure and properties of blends based on vulcanized rubber waste and styrene–butadiene–styrene thermoplastic elastomer

Ultra-Dispersed Powders Produced by High-Temperature Shear-Induced Grinding of Worn-Out Tire and Products of Their Interaction with Hot Bitumen.

Structural features of crumb rubber (CR) particles obtained by grinding on rollers and ultra-disperse powder elastomeric modifiers (PEM) obtained by high-temperature shear-induced grinding (HTSG) of CR or co-grinding with butadiene styrene thermoplastic elastomer (SBS) have been studied by electron and optical microscopy methods. Samples of modified bitumen were obtained at different mixing times (1–40 min) in a wide temperature range (120–180 °C). The products of interaction of PEM with hot bitumen precipitated on filters when washed with solvent from modified bitumen (MB) were studied by scanning electron microscopy (SEM). The self-similarity PEM particles and PEM breakdown fragments in bitumen up to the size of 100–200 nm were noted. The rapid (for 1 min) decomposition of PEM particles into fragments is shown, which is due to the specific structure formed as a result of HTSG. It has been suggested that this fragmentation may be caused by bitumen penetrating deep into the porous particle and breaking it, due to differently directed swelling pressure and precede the classical swelling associated with the penetration of solvent between rubber macromolecules, or occur concurrently with it.

Upgrading Toughness and the Glass Transition Temperature of Polydicyclopentadiene upon Addition of Styrene–Ethylene–Butylene–Styrene Thermoplastic Elastomer

Upgrading Toughness and the Glass Transition Temperature of Polydicyclopentadiene upon Addition of Styrene–Ethylene–Butylene–Styrene Thermoplastic Elastomer

Morphological Studies of Solution-Crystallized Thermoplastic Elastomers with Polyethylene Endblocks and a Random-Copolymer Midblock.

Styrenic thermoplastic elastomers (TPEs) in the form of triblock copolymers possessing glassy endblocks and a rubbery midblock account for the largest global market of TPEs worldwide, and typically rely on microphase separation of the endblocks and the subsequent formation of rigid microdomains to ensure satisfactory network stabilization. In this study, the morphological characteristics of a relatively new family of crystallizable TPEs that instead consist of polyethylene endblocks and a random-copolymer midblock composed of styrene and (ethylene-co-butylene) moieties are investigated. Copolymer solutions prepared at logarithmic concentrations in a slightly endblock-selective solvent are subjected to crystallization under different time and temperature conditions to ascertain if copolymer self-assembly is directed by endblock crystallization or vice versa. According to transmission electron microscopy, semicrystalline aggregates develop at the lowest solution concentration examined (0.01 wt%), and the size and population of crystals, which dominate the copolymer morphologies, are observed to increase with increasing aging time. Real-space results are correlated with small- and wide-angle X-ray scattering to elucidate the concurrent roles of endblock crystallization and self-assembly of these unique TPEs in solution.

Studies of the Sulfonated Hydrogenated Styrene-Isoprene-Styrene Block Copolymer and Its Surface Properties, Cytotoxicity, and Platelet-Contacting Characteristics.

Styrenic thermoplastic elastomers (TPEs) consist of styrenic blocks. They are connected with other soft segments by a covalent linkage and are widely used in human life. However, in biomedical applications, TPEs need to be chemically hydrogenated in advance to enhance their properties such as strong UV/ozone resistance and thermal-oxidative stability. In this study, films composed of sulfonated hydrogenated TPEs were evaluated. Hydrogenated tert-butyl styrene–styrene–isoprene block copolymers were synthesized and selectively sulfonated to different degrees by reaction with acetyl sulfate. By controlling the ratio of the hydrogenated tert-butyl styrene–styrene–isoprene block copolymer and acetyl sulfate, sulfonated films were optimized to demonstrate sufficient mechanical integrity in water as well as good biocompatibility. The thermal plastic sulfonated films were found to be free of cytotoxicity and platelet-compatible and could be potential candidates in biomedical film applications such as wound dressings.

Preparation and properties of ethylene-vinyl acetate copolymer-based blend foams

In this study, ethylene-vinyl acetate (EVA) copolymer-based blend foams with polyolefin elastomers (POEs), low-density polyethylene, or styrenic thermoplastic elastomers were prepared as a potential resilient material for reducing inter-floor noise. Various properties of EVA blend foams were measured in order to reveal the effects of EVA content and types of pair polymers consisting of EVA blend foams on dynamic stiffness, which is one of the key factors of resilient materials, in relation to hardness, specific gravity, and resilience. These properties had not been introduced by the construction industry until now. When the EVA/POE ratio was 20/80 and the foaming ratio was 210%, dynamic stiffness presented the lowest value at 5.97 MN m− 3. However, when the resilience was <20%, dynamic stiffness was as high as 37.66 MN m− 3 at an expansion ratio of 210% even when the specific gravity was low.

Stereoselective copolymerization of 4-(N,N-diphenylamino)styrene and isoprene by a C5H5-ligated scandium catalyst: synthesis of amino-functionalized crystalline styrenic thermoplastic elastomers

Amino-functionalized crystalline styrenic thermoplastic elastomers were prepared by carrying out stereoselective copolymerizations of 4-(N,N-diphenylamino)styrene and isoprene with the use of a C5H5-ligated scandium catalyst.

The Creation of Biologically Inert Elastomeric Material Based on Thermoplastic Elastomer Blends

Composites based on polyvinyl acetate, a copolymer of ethylene with a low vinyl acetate content, a divinyl styrene thermoplastic elastomer, and 3,4-isoprene rubber were developed for the production of sample specimens for children's creative play. Wide-ranging tests were carried out; results showed the total compliance of the developed composite materials with RFP and hygiene requirements.

Influence of carbonyl iron particle coating with silica on the properties of magnetorheological elastomers

In this paper, the influence of encapsulating carbonyl iron particles with various silica coatings on the properties of magnetorheological elastomers (MREs) was investigated. A soft styrene–ethylene–butylene–styrene thermoplastic elastomer was used as the composite’s polymer matrix. Spherical carbonyl iron powder (CIP) acted as the ferromagnetic filler. In order to improve the metal–polymer interaction, carbonyl iron particles were coated with two types of single and six types of double silica layers. The first layer was created through a TMOS or TEOS hydrolysis whereas the second one was composed of organosilanes. The mechanical properties of MREs containing 38.5 vol% of CIP were analysed under dynamic loading conditions. To investigate the magnetorheological effect in these composites, a 430 mT magnetic field, generated by an array of permanent magnets, was applied during testing. The results revealed that the magnetomechanical response of the MREs differs substantially, depending on the kind of particle coating.

Infection-resistant styrenic thermoplastic elastomers that can switch from bactericidal capability to anti-adhesion.

Styrenic thermoplastic elastomers (STPEs), particularly for poly(styrene-b-isobutylene-b-styrene) (SIBS), have aroused great interest in the indwelling and implant applications. However, the biomaterial-associated infection is a great challenge for these hydrophobic elastomers. Here, benzyl chloride (BnCl) groups are initially introduced into the SIBS backbone via Friedel-Crafts chemistry, followed by reaction with methyl 3-(dimethylamino) propionate (MAP) to obtain a cationic carboxybetaine ester-modified elastomer. The as-prepared elastomer is able to kill bacteria efficiently, while upon the hydrolysis of carboxybetaine esters into zwitterionic groups, the resultant surface has antifouling performances against proteins, platelets, erythrocytes, and bacteria. This STPE that switches from bactericidal efficacy during storage to the antifouling property in service has great potential in biomedical applications, and is generally applicable to the other styrene-based polymers.

첨가제에 따른 변성 스티렌계 열가소성 엘라스토머의 마찰에 의한 표면 파괴 거동 연구

본 연구에서는 실리카, 산화아연, 아연이온이 코팅된 실리카가 carboxylic acid로 변성된 스티렌계 열가소성 엘라스토머(m-TPS) film의 마찰시 표면 파괴에 미치는 영향을 관찰하였다. 일반 실리카를 첨가한 m-TPS film은 실리카 입자간의 강한 filler-filler interaction에 의한 낮은 분산성 때문에 기계적 강도, 내마모성과 마찰시 표면 파괴가 저하되는 것으로 나타났다. 산화아연 또는 아연이온이 코팅된 실리카를 첨가한 m-TPS는 zinc ion과 carboxylic acid group 간의 ionic cluster 형성을 통하여 기계적 강도, 내마모성과 마찰 시 표면 파괴가 개선되었다. Zinc ion과 carboxylic acid group 간의 ionic cluster 형성은 <TEX>$1550{\sim}1650cm^{-1}$</TEX>의 zinc carboxylate group stretch 피크의 FT-IR 분석 결과로 확인하였다. In this work, we observed the effect of silica, zinc oxide, zinc ion coated silica on carboxylic acid modified styrenic thermoplastic elastomer (m-TPS) film for friction-induced surface fracture. m-TPS film added general silica showed poor mechanical properties, anti-abrasion and friction-induced surface fracture, caused by strong filler-filler interaction of silica. In case of m-TPS films added zinc oxide or zinc ion coated silica, mechanical properties, anti-abrasion and friction-induced surface fracture were improved due to forming ionic cluster between carboxylic acid group of m-TPS and zinc ion. Ionic cluster were confirmed by FT-IR analysis that observed zinc carboxylated group stretch peak at <TEX>$1550{\sim}1650cm^{-1}$</TEX>.

Conductive elastomeric nanocomposites based on oxidation of aniline with silver nitrate via inverse emulsion polymerization

The present investigation describes a facile and rapid approach of conductive nanocomposites production and assesses the opportunity of their use as electro-mechanical sensors. Hybrid materials containing silver and polyaniline nanoparticles reinforcing a thermoplastic elastomeric matrix were studied. The approach developed includes ultrasonically assisted in situ inverse emulsion polymerization of aniline oxidized by a weak oxidant and silver nitrate, and supported with a strong oxidant, ammonia peroxydisulfate. Aniline was doped with dodecylbenzene sulfonic acid in the presence of dissolved styrene–isoprene–styrene thermoplastic elastomer. While conventional polymerization of aniline with silver nitrate takes 2 weeks, by utilization of inverse emulsion polymerization, the reaction time reduces to 5 days. The assistance of a strong oxidant dramatically shortens the reaction time to 30 min. The technique developed results in uniform distribution of polyaniline/silver (PANI/Ag) conductive nanoparticles in the elastomeric matrix. The morphological studies of the films reveal spherically shaped 45 nm Ag particles. The presence of PANI/Ag in the styrene–isoprene–styrene elastomeric matrix enhances the electrical, thermal, and mechanical properties of the nanocomposites. The approach described provides an opportunity of the development of tunable structures and a remarkably distinctive architecture. A rapid electrical resistance response to an applied strain makes the nanocomposites developed useful as sensitive strain sensors. Copyright © 2014 John Wiley & Sons, Ltd.

Sustainable Thermoplastic Elastomers from Terpene-Derived Monomers.

ABA triblock polymers were prepared by living anionic polymerization of the pinene-derivable monomers α-methyl-p-methylstyrene and myrcene. The resulting thermoplastic elastomers displayed microphase separation at moderate molar mass, an upper service temperature about 70 °C higher than traditional petroleum-derived styrenic thermoplastic elastomers, competitive tensile strengths of up to 10 MPa, impressive ultimate elongations of up to 1300%, and remarkably low energy loss recovery attributes.

Effect of combined fatigue and chemical aging conditions on the mechanical property, structure, and morphology of styrene–butadiene–styrene elastomer

The mechanical property, structure, and morphology of styrene–butadiene–styrene (SBS) thermoplastic elastomer under the combined fatigue and chemical aging conditions were investigated. The results indicated that under the fatigue condition alone, the tensile strength of SBS increased initially and then decreased with the increase in fatigue time. Cracks formed on the surface of samples. Through transmission electron microscopy analysis, it was found that the phase morphology was influenced by fatigue condition. However, there was no significant change in the molecular weight and chemical structure of SBS. Under combined fatigue and chemical aging conditions, the chemical aging process could be accelerated by the fatigue condition. Molecular weight and gel content significantly increased with the increase of fatigue condition. Under ultraviolet (UV) light irradiation alone, there was no crack on the surface of SBS. After adding the fatigue condition, a large deterioration formed on the surface of SBS sample. The chemical aging condition such as UV light and temperature could also promote the fatigue aging process. With the addition or increase of chemical aging condition, the tensile strength of SBS greatly decreased. The oxygen content and gel content significantly increased, and there were a lot of cracks forming on the surface of SBS sample.

Functionalization and hemocompatibility of a styrenic thermoplastic elastomer based on its epoxidized precursor

ABSTRACTPoly(ethylene glycol) monomethyl ether (mPEG) was introduced into a glycidyl methacrylate‐modified styrenic thermoplastic elastomer graft copolymer via a ring‐opening reaction with the epoxy group. The chemical compositions of the samples were confirmed by Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and gel permeation chromatography. X‐ray photoelectron spectroscopy, atomic force microscopy, and water contact angle measurement were used to investigate the surface properties. The results show that the molecular weight of the mPEG monomer had a great effect on the surface properties of the modified samples. The platelet adhesion and protein adsorption of the samples modified with low‐molecular‐weight mPEG were reduced dramatically relative to those of the virgin styrenic thermoplastic elastomer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40518.