B-polystyrene Triblock Copolymers Research Articles

Micelles regulated thin film nanocomposite membrane with enhanced nanofiltration performance

The desalination performance of thin film nanocomposite (TFN) membranes is significantly influenced by the nature of nanofillers and the structure of the polyamide (PA) layer. Herein, a micelles regulated interfacial polymerization (MRIP) strategy is reported for the preparation of TFN membranes with enhanced nanofiltration (NF) performance. Specially, stable and ultrafine micelles, synthesized from the poly(ethylene oxide)-b-poly(4-vinyl pyridine)-b-polystyrene (PEO-PVP-PS) triblock copolymers, were utilized as regulators in the aqueous phase during the interfacial polymerization (IP) process. TFN membranes were fabricated with varying concentrations of micelles to improve their properties and performances. The structure of the PA layer was further regulated by modulating the content of trimesoyl chloride (TMC), which significantly enhances the performance of the TFN membrane with micelles. Attributable to the homogeneously dispersed micelles and the modified PA layer, the optimized membrane denoted as TFN-2–0.3 exhibits an improved separation performance of 20.7 L m-2h−1 bar−1 and 99.3 % Na2SO4 rejection, demonstrating nearly twice the permeance and 2.7 % higher rejection than that of the original control membrane, respectively. The mechanism of this MRIP strategy was investigated through the diffusion experiments of piperazine (PIP) and interfacial tension tests. The incorporated micelles effectively lower the interfacial tension, promote the diffusion of PIP and accelerate the IP reaction, resulting in a denser and thinner PA layer. Collectively, these findings demonstrate that TFN membranes with micelles exhibit increased roughness, enhanced hydrophilicity, superior rejection to divalent salts, and better acid-base resistance, highlighting their potential applications in the design of TFN membranes.

Effects of a Nanophase-Separated Structure on Mechanical Properties and Proton Conductivity of Acid-Infiltrated Block Polymer Electrolyte Membranes under Non-Humidification.

Acid-infiltrated block polymer electrolyte membranes adopting a spherical or lamellar nanophase-separated structure were prepared by infiltrating sulfuric acid (H2SO4) into polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S-P-S) triblock copolymers to investigate the effects of its nanophase-separated structure on mechanical properties and proton conductivities under non-humidification. Lamellae-forming S-P-S/H2SO4 membranes with a continuous hard phase generally exhibited higher tensile strength than sphere-forming S-P-S/H2SO4 membranes with a discontinuous hard phase even if the same amount of Sa was infiltrated into each neat S-P-S film. Meanwhile, the conductivities of lamellae-forming S-P-S/H2SO4 membranes under non-humidification were comparable or superior to those of sphere-forming S-P-S/H2SO4 membranes, even though they were infiltrated by the same weight fraction of H2SO4. This result is attributed to the conductivities of S-P-S/H2SO4 membranes being greatly influenced by the acid/base stoichiometry associated with acid-base complex formation rather than the nanophase-separated structure adopted in the membranes. Namely, there are more free H2SO4 moieties that can release free protons contributing to the conductivity in lamellae-forming S-P-S/H2SO4 membranes than sphere-forming S-P-S/H2SO4, even when the same amount of H2SO4 was infiltrated into the S-P-S.

Exploiting the lower disorder-to-order temperature in polystyrene-b-poly(n-butyl acrylate)-b-polystyrene triblock copolymers to increase their flow resistance at high temperature

This work focuses on the temperature-dependent structural and rheological characterization of polystyrene-b-poly(n-butyl acrylate)-b-polystyrene triblock copolymers (PS-b-PnBA-b-PS) in the melt and, in particular, on their ability to show a lower disorder-to-order temperature (LDOT). To this aim, copolymers of varying block lengths, but keeping the PnBA block as a major component, were synthesized. Small-angle x-ray scattering revealed that the copolymers with short PS blocks (∼10 kg/mol) approach an LDOT but do not cross it. At room temperature, these copolymers exhibit higher moduli compared to a PnBA homopolymer due to the reinforcing effect of the PS but are flowing at temperatures above the glass transition of the PS. Increasing the PS and PnBA block length, to keep the same PS fraction, induces more profound changes in the structural and viscoelastic behaviors. Such a copolymer crosses the LDOT, leading to a microphase-separated and ordered state at high temperature. Contrary to the copolymers with short PS blocks, the flow regime was not reached, even at temperatures well above the glass transition of the PS. Instead, a low-frequency plateau was observed in rheology, showing the increased lifetime of the microphase-separated PS domains. ABA triblock copolymers exhibiting an LDOT behavior could, thus, be of interest for the design of thermoplastic elastomers or pressure-sensitive adhesives that can resist the flow at high temperatures.

Synthesis and properties of ABA type triblock copolymer from poly(dimethylsiloxane) macroinitiator: Development of novel attachable initiators for atom transfer radical polymerization

A sequence of ABA-type polystyrene-b-poly(dimethylsiloxane)-b-polystyrene (PS-b-PDMS-b-PS) triblock copolymers were synthesized by ATRP (Atom Transfer Radical Polymerization) after appropriate end functionalization of vinyl terminated PDMS. Vinyl terminated PDMS was reacted with a 3-chloropropane thiol to synthesize a halo terminated macroinitiator. Subsequently, this macroinitiator was used to synthesize ABA-type block copolymers. The resulting block copolymers were characterized to confirm the presence of PDMS & PS blocks. The theoretical molecular weight and GPC was used to verify the high molecular weight of the ultimate block copolymer. The results show that the PS chains were successfully bound to the PDMS backbone and molecular weight linearly increased with time during the controlled polymerization. The functionality of the given polymer was confirmed by FT-IR analysis, 1H NMR, and 13C NMR spectra. The thermal stability increased after the addition of PS with PDMS. Additionally, the EDS analysis confirms the halogen content. DLS verified the particle size, whereas SEM was used for the morphology of the nanoaggregates. This triblock has good moisture resistance & thermal stability as determined by thermogravimetric analysis. The formation of PDMS blocks increased the hydrophobicity of the PS and contact angle analysis confirmed this.

Anion Exchange Membranes for Fuel Cells Based on Quaternized Polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene Triblock Copolymers with Spacer-Sidechain Design.

This work studied the polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymers functionalized by butyl quaternary ammonium (C4Q) groups and alkyl side chains of different chain lengths (Cn, n = 0 to 24). The hydrated membrane morphology was modeled by dissipative particle dynamics simulation at hydration levels from 10 to 30. A hydroxide model was devised to characterize the diffusivity of anions under the coarse-grained framework. In general, the ionomers with alkyl side chains provided ion conductivity of a similar level at a lower ion exchange capacity. All hydrated SEBS–C4Q–Cn ionomers showed clear phase separation of the hydrophobic and hydrophilic domains, featuring 18.6 mS/cm to 36.8 mS/cm ion conductivity. The hydrophilic channels expanded as the water content increased, forming more effective ion conductive pathways. Introducing excess alkyl side chains enhanced the nano-segregation, leading to more ordered structures and longer correlation lengths of the aqueous phase. The membrane morphology was controlled by the length of alkyl side-chains as well as their tethering positions. Ionomers with functionalized side chains tethered on the same block resulted in well-connective water networks and higher conductivities. The detailed structural analysis provides synthesis guidelines to fabricate anion exchange membranes with improved performances.

Thermal and morphological study of paraffin/SEBS/expanded graphite composite phase change material for thermal energy storage

ABSTRACT This work aims to develop a high thermal conducting and leakage-proof composite phase change material (CPCM) for thermal energy storage (TES) applications. A leakage-proof shape-stable phase change material (SPCM) has been prepared by impregnating paraffin into the network of polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene (SEBS) tri-block copolymer. In order to improve the thermal conductivity of paraffin/SEBS composite, expanded graphite (EG) has been directly incorporated into paraffin/SEBS (4:1) composite. Two different mass fractions of EG, i.e., 1 wt% and 5 wt%, have been chosen for the thermophysical study of leakage-proof SPCM named CPCM1 and CPCM2, respectively. Structural, morphological, and thermal studies of prepared composites have been carried out by XRD, FTIR, SEM, TGA, and DSC. The latent heats of prepared SPCM, CPCM1, and CPCM2 composites have been found as 167.91 J/g, 163.25 J/g, and 146.71 J/g, respectively. The thermal conductivities of composites have been measured by Laser Flash Apparatus (LFA). Results show that the thermal conductivity (TC) of CPCM1 and CPCM2 remarkably increases to 0.501 Wm−1K−1 and 1.301 Wm−1K−1, respectively, which is 2.8 and 7.35 times of paraffin/SEBS composite (0.177 Wm−1K−1). Therefore, findings suggest that the CPCM1 and CPCM2 samples have a great potential for TES application, specifically for solar water heating systems.

Preparation and Self-Assembling of PLA-b-PNIPAM-b-PS Triblock Copolymer Thin Films.

Polylactide-b-poly(N-isopropylacrylamide)-b-polystyrene (PLA-b-PNIPAM-b-PS) triblock copolymers (tri-BCPs) with various chemical compositions (block ratio) were prepared from the combination of ring-opening polymerization and reversible addition-fragmentation chain transfer polymerization. Subsequently, the self-assembling behaviors of these tri-BCP films obtained from spin-coating were investigated by annealing them under different solvent atmosphere. We found that these films could self-assemble into various morphologies due to the microphase separation of incompatible copolymer blocks. Atomic force microscopy confirmed the perpendicular cylindrical morphology self-assembled from PLA4.5k-b-PNIPAM5.2k-b-PS22.4k tri-BCP film under mixed solvent atmosphere of toluene/acetone (7:3, v/v). Self-assembled PLA cylinders are evenly distributed among the PS matrix and perpendicular to the film surface, with PNIPAM component taking place at the PLA/PS interphase. Furthermore, by etching the degradable PLA component, porous PS film decorated with PNIPAM "brushes" hoisting channels were generated. This work provides a facile method and detailed protocol for fabricating stimuli-responsive porous films which are promising for thermoresponsive "smart" separation technologies.

Melt-Fabricated Photoreactive Block Copolymer Micelles as Building Blocks for Tunable Elastomeric Hydrogels

Soft, conformally shaped thermoplastic elastomer (TPE) hydrogels producible from a moldable precursor material are desirable in many biomedical, surgical, and pharmaceutical applications. An innovative class of hydrogel networks was developed by employing photocurable, moldable solutions of melt-assembled spherical micelles formed from ω-anthracenylpolystyrene-b-poly(ethylene oxide) diblock copolymer. Photoinduced [4 + 4] cycloaddition (λ = 365 nm) of terminal anthracene groups populating the hydrophilic corona of each micelle was used to produce polystyrene-b-poly(ethylene oxide)-b-polystyrene triblock copolymer tethers or network strands among adjacent micelles. Structural uniformity in the micelle population was confirmed by small-angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM), and dynamic light scattering (DLS). Homogeneous dispersal of the assembled micelle building blocks in water resulted in spreadable or moldable photoactive micelle solutions, studied for their stability in solution and ability to rapidly form elastomeric hydrogels once irradiated. Once in molds, these solutions of varied concentration were irradiated to form soft TPE hydrogels with dynamic shear modulus controllable with irradiation time (triblock copolymer content), exhibiting prescribed shape consistent with high-fidelity conformal fill.

Ag nanoparticles encapsulated in carboxyl-functionalized hollow microporous organic nanospheres for highly efficient catalysis applications

In this work, we present a novel synthesis of Ag nanoparticles encapsulated in carboxyl-functionalized hollow microporous organic nanospheres (Ag@COOH-HMONs) by a combination of hyper-cross-linking mediated self-assembly and simply impregnation method, in which the COOH-HMONs supports were prepared via a Friedel-Crafts alkylation reaction by using polylactide-b-poly(tertbutyl acrylate)-b-polystyrene (PLA-b-PtBA-b-PS) triblock copolymer as precursors. Owing to the abundant carboxyl groups in the cavity of COOH-HMONs, highly dispersed silver nanoparticles can be successfully anchored into COOH-HMONs to produce Ag@COOH-HMONs via an ion exchange with AgNO3 following by an in-situ reduction of sodium borohydride (NaBH4). The obtained Ag@COOH-HMONs exhibit the high catalytic activities for the reduction of MB and nitroaromatic compounds as well as selective oxidation of thiol and styrene due to their high surface area, hierarchical porosity and yolk-shell nanostructure. This approach of constructing novel metal@porous organic polymers is expected to open doors for new types of yolk-shell structural catalysts for practical applications.

Spatial Control of Mechanical Properties and Surface Topography in a Photoreactive Block Copolymer Hydrogel

A simple method for spatially directed mechanical reinforcement and surface feature introduction on a photoactive block copolymer-based thermoplastic elastomer hydrogel is presented. The hydrogel material comprises two primary spherical micelle-forming block copolymer species: photoactive ω-anthracenylpolystyrene-b-poly(ethylene oxide) diblock copolymer (SO-anth) and polystyrene-b-poly(ethylene oxide)-b-polystyrene triblock copolymer (SOS). The PEO midblock of the SOS triblock copolymer species provides a physical tether between adjacent micelles, increasing mechanical robustness (modulus) with addition of bridging SOS chains. The photoactive SO-anth diblock copolymer contains a terminal anthracene unit capable of dimerization by application of 365 nm light to induce a [4 + 4] photocycloaddition. The ability to photocouple chain termini populating the outer shell of the hydrophilic micelle coronas produces additional SOS triblock copolymer in situ. While the initial population of SOS tethers act to form a...

A new low moduli dielectric elastomer nano-structured composite with high permittivity exhibiting large actuation strain induced by low electric field

Dielectric elastomers (DEs) are able to deform significantly in response under an external electric field. DE actuators have promising applications in many emerging fields such as biomimetic robots, haptic devices, tunable lens, and loudspeakers. Practical applications of DE devices are limited by the extremely high electric field and the high pre-stretch. Herein, we have designed and fabricated a new type of soft DE composites of partially reduced graphene oxide (RGO)/polystyrene-b-poly (n-butyl acrylate)-b-polystyrene triblock copolymer (SBAS). An extremely soft SBAS was tailor-made as the elastic matrix. A facile colloidal blending method, i.e. simply mixing the SBAS latex with GO aqueous dispersion, was used to fabricate the nano-structured composite with a segregated network of RGO nano-sheets. The design strategy led to the DE composite film of 1.5 wt% RGO/SBAS owning low modulus (0.51 MPa), high relative permittivity (∼11) and relatively high dielectric breakdown strength (33 kV/mm). The DE composite film exhibited 21.3% maximum area actuation strain at relatively low electric field strength 33 kV/mm without pre-stretch.

Quaternized triblock polymer anion exchange membranes with enhanced alkaline stability

Alkaline stability is the critical issue for the practical application of anion exchange membranes (AEMs) in fuel cells. The benzyltrimethyl ammonium and backbone with C-O linkages of the traditional AEMs are susceptible to attack by hydroxide ions resulting in poor alkaline stability of the AEMs. Herein, we present the preparation of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymer via grafting, ketone reduction and quaternization for AEM fuel cell applications. The quaternary ammonium (QA) groups are attached to the SEBS backbone free of C-O linkages via long flexible alkyl spacers, which are responsible for the robust alkaline stability of the AEMs. Thus, the hydroxide conductivity of SEBS-CH2-QA-1.5 was only decreased by 7.7% and 13.7% after immersing the membranes into a 1M aqueous KOH solution at 60 and 90°C for 360h, respectively. Furthermore, SEBS-CH2-QA-1.5 with IEC of 1.23meqg−1 exhibits a maximum hydroxide conductivity of 56.4mScm−1 at 80°C and a maximum power density of 94.6mWcm−2 under a current density of 300mAcm−2.

Interfacial molecular dynamics of styrenic block copolymer-based nanocomposites with controlled spatial distribution

The dielectric properties of nanocomposites of polystyrene-b-poly (ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymers containing organically modified clay nanoparticles featuring controlled spatial orientation at the nanoscale: isotropic, totally oriented and partially oriented, have been investigated and correlated with the nanocomposite morphologies. A slow dielectric relaxation process attributed to elastomer chains with reduced mobility confined at nanoparticle/polymer interphase was observed in all the nanocomposites and was found to be dependent on the orientation of nanoclay and polystyrene (PS) domains, the location of clay tactoids as well as the PS block fraction. A dielectric “interfacial” glass transition temperature Tgi assigned to this characteristic relaxation was estimated to occur at temperatures ranging between 6 °C and 35 °C depending on the nanocomposite, which is much higher than the bulk rubber phase glass transition temperature, normally lower than −40 °C for the studied block copolymers. Interestingly, the highest Tgi were associated with the nanocomposites featuring random or partial orientation and/or selective location of nanoparticles in the rubber phase.

Elastic free-standing RTIL composite membranes for CO2/N2 separation based on sphere-forming triblock/diblock copolymer blends

Solvent-free, melt-state self-assembly of sphere-forming polystyrene-b-poly(ethylene oxide) diblock copolymer/polystyrene-b-poly(ethylene oxide)-b-polystyrene triblock copolymer (SO/SOS) blends was used to produce free-standing, room-temperature ionic liquid (RTIL) composite membranes with excellent mechanical properties and CO2/N2 separation performance. Membranes were prepared from vitrified SO/SOS diblock/triblock melts by swelling to greater than 94wt% 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) ionic liquid. These free-standing composite membranes were evaluated for their CO2/N2 separation performance over a range of transmembrane pressures (26-413 kPa), with results traversing the 2008 Robeson upper bound. Even with such high loadings of neat [EMIM][TFSI], these membranes exhibit the mechanical properties of solid elastomers, evident by the ultimate tensile strength of 250kPa and the compressive modulus at 40% strain of 348kPa for the membranes with 46% triblock copolymer content (SOS46). Cyclic loading and unloading in both tension and compression revealed reversible elasticity, with no mechanical property degradation or permanent hysteresis detected. For each composition studied, membrane failure occurred at uniaxial extension ratios of 3.8. The CO2 permeability performance of these membranes was stable for 28 days of testing with no detectable RTIL leakage. Transmembrane pressures exceeding 400kPa could be accommodated, with cyclic application of transmembrane pressure differentials at 230kPa producing neither plastic deformation nor diminished performance in gas separations. Such behavior is intimately tied to the highly distensible and elastic nature of the melt-assembled diblock/triblock network underpinning this RTIL-based composite membrane design.

Morphological evolution of block copolymer nanocomposites submitted to extensional flows

In this work, the effect of extensional flow on the morphology of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymers and their clay-containing nanocomposites was evaluated. Four types of SEBS copolymers with different block compositions and cylindrical morphology were chosen to understand the effects of cylinder orientation and state of clay dispersion on the evolution of morphology during extensional flow. The effect of clay concentration (ranging from 2.5 to 7.5 wt. %) was also studied. The samples were subjected to extensional flow using a Sentmanat extensional rheometer attached to a rotational rheometer at Hencky strain rates varying from 0.01 to 20 s−1. Small angle X-ray scattering analysis was subsequently performed to evaluate the morphological changes caused by extensional flow. When preoriented block copolymers [SEBS-30% PS (polystyrene)] and their nanocomposites undergo elongation, the styrene cylinders and clay nanoparticles align themselves in the flow direction and their rheological behavior and morphological evolution are influenced by the stretching direction (longitudinal and transverse), strain rate magnitude, clay concentration, and dispersion state of the clay nanoparticles. When isotropic block copolymers (SEBS-13% PS) undergo elongation, it was observed that the PS cylinders only exhibit structural alignment in the stretching direction in the presence of clay. Block copolymer molecules can exhibit different relaxation times depending upon the volume fraction of PS domains (13% or 30%). The addition of clay, however, hinders complete relaxation, helping to promote a permanent domain alignment after flow cessation, especially in hard-to-align copolymers.

Cobalt Mediated Radical Polymerization of 4-Bromo-2, 6-Dimethyl Phenol and Its Copolymerization with Poly (dimethyl siloxane) in the Presence of Co(acac)2: DMF Catalyst

Novel well-defined poly(phenylene oxide) (PPO)-based block copolymers were polymerized from 4-bromo-2,6-dimethylphenol (BDMP) in the presence of a cobalt acetylacetonate (Co(acac)2) catalyst with dimethyl formamide (DMF) as a ligand and initiated with benzoyl peroxide (BPO) at 60 °C in a novel controlled copolymerization reaction within a good yield. The monomer copolymerized with vinyl acetate (VAc), poly(methyl methacrylate)-b-poly(dimethyl siloxane)-b-poly (methyl methacrylate) (PMMA-b-PDMS-b- PMMA) and polystyrene-b-poly(dimethyl siloxane)-b-polystyrene (PSt-b-PDMS-b-PSt) triblock copolymers in good yield. Characterization indicated a very narrow molecular weight distribution. The block copolymer indicated a new microstructure of phenylene oxide which was analyzed by proton-nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetriy (DSC) and gel permeation chromatography (GPC). Meanwhile, the number average molecular weights calculated from the 1H-NMR spectra were in very good agreement with the theoretically calculated values. The DSC results also indicated the successful formation of these new block copolymers.

Thermoresponsive aggregation of PS–PNIPAM–PS triblock copolymer: A combined study of light scattering and small angle neutron scattering

The aggregate structure of a thermoresponsive polystyrene–b-poly(N-isopropylacrylamide)–b-polystyrene (PS–PNIPAM–PS) triblock copolymer was investigated as a function of temperature in aqueous solutions by the combination of small angle neutron scattering (SANS) and dynamic/static light scattering (LS). SANS shows that the system consists of spherical intermicellar aggregates which self-assemble into larger clusters either at temperatures below or above the lower critical solution temperature (LCST). Upon the solubility transition of PNIPAM the mass of the clusters increases significantly, whereas their size remains constant and the size of the intermicellar aggregates decreases. This picture is consistent with the LS data where the signature of the two entities in solution is observed. The combination of LS and SANS studies has presented a clearer scenario on the thermoresponsive aggregation behavior of the investigated PS–PNIPAM–PS triblock copolymer.

Role of surfactant on inducing specific microdomains of block copolymer: An example case from polystyrene-b-poly(ethylene-co-1-butene)-b-polystyrene (SEBS) electrospun thermoplastic-elastomer fiber containing polyethylene glycol lauryl ether (PGLE)

The present work demonstrates a simple approach to control microdomains in thermoplastic elastomer by using surfactants based on a good example of polystyrene-b-poly(ethylene-co-1-butene)-b-polystyrene triblock copolymer (SEBS) containing polyethylene glycol lauryl ether (PGLE) electrospun fibers. The interaction between PGLE and the phenyl group of PS in SEBS chain is a key factor to allow PGLE functioning in changing morphology of the SEBS micro-fibers. In general, SEBS electrospun fibers show distorted and fragmented lamellae. By adding only 1 wt% of PGLE in SEBS, the PGLE retards the microdomain distortion as well as initiates isotropic lamellar orientation. When fiber stretching force reached a certain level, the fragmented lamellar of SEBS-PGLE is initiated, and at that time, the tensile strength of the fibers increases significantly.

Modulation of the electrochemical properties of SBS-based anionic membranes by the amine molecular structure

Abstract In this work, different amines (bifunctional, as diazabicyclo[2.2.2]octane (Dabco) and monofunctional, as N-methylimidazole or trimethylamine) were utilized for the amination of benzyl chloride-grafted polystyrene-b-poly(butadiene)-bpolystyrene triblock copolymers (SBS-g-VBC). The use of Dabco solutions in mixture with variable amounts of monoamine or at different concentration allowed to modulate the degree of crosslinking of the SBS-based membranes and their electrochemical parameters. More specifically, tuning Dabco concentration permitted the reduction of water uptake without significantly affecting ionic conductivity.

Synthesis and Characterization of Poly (phenylene oxide)-Based Block Copolymers via Cobalt Mediated Radical Polymerization (CMRP)

Novel well-defined poly(phenylene oxide) (PPO) based block copolymers were polymerized from 4-bromo-2,6-dimethylphenol (BDMP) in the presence of a cobalt acetylacetonate (Co(acac)2) catalyst with dimethyl formamide (DMF) as a ligand and initiated with benzoyl peroxide (BPO) at 60 °C. The monomer copolymerized with vinyl acetate (VAc), polymethyl(meth)acrylate-b-poly(dimethyl siloxane)-b-polymethyl(meth)acrylate (PMMA-b-PDMS-b-PMMA) and polystyrene-b-poly(dimethyl siloxane)-b-polystyrene (PSt-b-PDMS-b-PSt) triblock copolymers in good yield. Characterization indicated a very narrow molecular weight distribution. The solid polymer obtained is a stable polymer with high thermal stability at 220 °C. The block copolymer indicated a new microstructure of phenylene oxide which was analyzed by proton-nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetriy (DSC) and gel permeation chromatography (GPC). Meanwhile, the number average molecular weights calculated from the 1H-NMR spectra were in very good agreement with the theoretically calculated values. The DSC results also indicated the successful formation of these new block copolymers.