[-PPO-PDMS-PHS-]n三元多嵌段共聚物的形态结构和性能

利用DMA, TEM和SAXS对以聚苯醚(PPO)为硬段、聚对羟基苯乙烯(PHS)为半硬段和聚二甲基硅氧烷(PDMS)为软段的三元多嵌段共聚物[-PPO-PDMS-PHS-]n以三种嵌段相容相为连续相, PPO与PHS的相容相和PDMS相为两种分散相, 其tan δ随温度变化曲线在-100℃至200℃一直是一很高的平台, 并具有优异的力学性能, 较好地解决了含有机硅类嵌段共聚物强度低的弱点, 同时又保留了嵌段共聚物微相分离的特性。     

Synthesis of poly[arylene ether sulfone-b-vinylidene fluoride] block copolymers

A series of α,ω-dihydroxy polyarylene sulfones (PAES) were synthesized comprising bisphenol A (PAES1, M_n=1800, 4900, and 9500 daltons), 4,4^′-biphenol (PAES2, M_n=4100 daltons), and hexafluorobisphenol A (PAES3, M_n=3300 daltons). These were reacted with α,ω-dibromo poly(vinylidene fluoride) (PVDF, M_n=1200 daltons) prepared by telomerization, to yield block copolymers possessing rigid and flexible segments. Block copolymers were characterized by FTIR, NMR, GPC, DSC, TGA and TEM. In several cases the block copolymers exhibited distinct thermal transitions, i.e. T_m and T_g for PVDF and PAES segments, respectively. Where observable, T_g of PAES domains in the block copolymers occurred at a temperature lower than the corresponding PAES homopolymer due to the flexible nature of the surrounding PVDF domains. Block copolymers exhibited a similar thermal stability to the corresponding PAES homopolymers but higher stability than the PVDF homopolymer, and much higher still than α,ω-dibromo PVDF. TEM analyses indicate that phase separation of PAES and PVDF domains occurs on the nanometer scale.     

Incorporation of polydimethylsiloxane into polyurethanes and characterization of copolymers

Novel copolymers of polyurethane (PU) were prepared by direct transurethanetion reaction of a commercial PU with polydimethylsiloxanes (PDMS, MW 1000, 5000, and 10,000) containing hydroxyl end-groups. Transurethanetions with different mass ratios of hydrophobic PDMS to hydrophilic PU chains (PDMS1000–PU: 43:57, 67:33, 71:29, and 80:20; PDMS5000–PU: 37:63, and 51:49; PDMS10000–PU: 51:49) were carried out in solution at 65 and 100 °C. In catalyzed reactions, dibutyltin dilaurate (SnC₃₂H₆₄O₄) was used to promote bond breaking in the PU chain and accelerate the reaction between hydroxyl end-groups of PDMS and regenerated isocyanates of PU. The chemical structures of the prepared copolymers were comprehensively characterized by ¹H, ¹³C, and ²⁹Si NMR spectroscopies. According to elemental analysis, the content of PDMS varied between 3 wt.% and 16 wt.%, and results obtained from the ¹H NMR spectroscopy were in good agreement with the results of elemental analysis. Increased length of the hydrophobic chain increased the content of PDMS in the copolymer. The GPC results showed that molar masses of the PUPDMS copolymers were lower than the molar mass of the starting PU. The glass transitions (T_g) of the copolymers were shifted to lower temperature as compared with T_g of the starting polyurethane. ATR FTIR spectroscopy showed the surface of the copolymer films to be enriched with siloxane groups and, according to electron microscopy, it was textured with microspheres. The static contact angles for copolymer films measured with deionized water ranged from 94° to 117°. The different structural, thermal and surface properties of the PUPDMS copolymers as compared with PU indicated that transurethanetion had taken place.     

Synthesis and properties of polyetheretherketone–polydimethylsiloxane block copolymers

Polyetheretherketone-polydimethylsiloxane (PEEK–PDMS) block copolymers were synthesized from the condensation of dimethylamino terminated PDMS and hydroxy terminated PEEK oligomers in 1-chloronapthalene. Yields for block copolymers synthesised from low molecular weight PDMS oligomers were good but yields were significantly reduced when higher molecular weight PDMS oligomers were used. This was related to the limited solubility of higher molecular weight PDMS in the reaction solvent. Differential scanning calorimetry (DSC) studies indicated that phase separation of the block copolymers occurred at very short segment length (M?_n < 4000). A depression in the crystallinity of both the PEEK and PDMS phases in the block copolymer was observed. Thermogravimetric analysis (TGA) studies indicated that the PEEK–PDMS block copolymers displayed insufficient thermo-oxidative stability to be melt-processed successfully in PEEK based blends.     

Perfectly alternating segmented polyimide-polydimethyl siloxane copolymers via transimidization

New strategies for the synthesis of perfectly alternating segmented polyimide-polydimethyl siloxane copolymers were developed by utilizing a transimidization method. Imide oligomers endcapped with 2-aminopyrimidine were reacted with aminopropyl terminated (dimethyl siloxane) oligomers to afford perfectly alternating segmented imide siloxane copolymers. The polymerization was conducted in solvents such as chlorobenzene and chlorofrom. High molecular weight, fully imidized perfectly alternating segmented imide siloxane copolymers were obtained within 2 h at temperatures of 60-110°C. The mechanism of the reaction was further elucidated via model compounds and NMR characterization. The block copolymers exhibited two T_gs due to the microphase separation of the polyimide and polysiloxane phases. The T_g of the polyimide phase was a function of the length of the polyimide block. However, partial phase mixing was also evident from the DSC results on the imide siloxane copolymers prepared with low molecular weight polyimide segments. Thermooxidative stability and tensile properties of the perfectly alternating segmented imide siloxane copolymers were found to be principally dependent on the amount of poly (dimethyl siloxane) incorporated in the copolymer and did not correlate with the poly (dimethyl siloxane) or polyimide block lengths. The stress-strain behavior of both solvent cast films or molded films is also reported. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of (AB)n-type poly(l-lactide)-poly(dimethyl siloxane) multiblock copolymer and the effect of its macrodiol composition on urethane formation

An (AB)_n-type multiblock copolymer containing alternating poly(l-lactide) (PLLA) and poly(dimethyl siloxane) (PDMS) segments was synthesized by chain extension of hydroxyltelechelic PLLA-PDMS-PLLA triblock copolymers, which were prepared by the ring-opening polymerization of l-lactide initiated by α,ω-functionalized hydroxyl poly(dimethyl siloxane), using 1,6-hexamethylene diisocyanate as a chain extender. The triblock and the multiblock copolymers were characterized by FT-IR, ¹H NMR and GPC. From the results of thermal analysis, two glass transition temperatures which were measured by DSC showed the occurrence of phase separation phenomena in the triblock and multiblock copolymers because of the difference of solubility parameters between PLLA and PDMS segments. The effect of the chemical composition of the triblock copolymers, including the Mw and the constitutive segment chain length of the macrodiol, on the development of the Mw of the multiblock was discussed based on diffusion effect. Furthermore, the consumption of the isocyanate groups was determined by FT-IR to investigate the dependence of the reaction kinetics of the urethane formation on the chemical composition of the triblock copolymer. The results reveal that the order of the chain extension reaction depended on the Mw of the triblock copolymer: a second order reaction was transformed into a third reaction as the Mw of the triblock copolymer increased from 7000 to 25,000 (g/mol) perhaps because of the inhibition of the formation of an active complex involved in the catalyzed-urethane reaction by the polymer chain aggregation. Finally, the mechanical properties of the multiblock copolymers demonstrated that the introduction of the extremely flexible PDMS segment substantially improved the elongation at breakage, and the tensile strength and the tensile modulus declined due to the intrinsic elasticity of such segments.     

Synthesis of star‐shaped copolymers with methyl methacrylate and n‐butyl methacrylate by metal‐catalyzed living radical polymerization: Block and random copolymer arms and microgel cores

Various star‐shaped copolymers of methyl methacrylate (MMA) and n‐butyl methacrylate (nBMA) were synthesized in one pot with RuCl₂(PPh₃)₃‐catalyzed living radical polymerization and subsequent polymer linking reactions with divinyl compounds. Sequential living radical polymerization of nBMA and MMA in that order and vice versa, followed by linking reactions of the living block copolymers with appropriate divinyl compounds, afforded star block copolymers consisting of AB‐ or BA‐type block copolymer arms with controlled lengths and comonomer compositions in high yields (≥90%). The lengths and compositions of each unit varied with the amount of each monomer feed. Star copolymers with random copolymer arms were prepared by the living radical random copolymerization of MMA and nBMA followed by linking reactions. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 633–641, 2002; DOI 10.1002/pola.10145     

Mechanical properties of gradient copolymers of styrene and n‐butyl acrylate

The mechanical properties of linear and V‐shaped compositional gradient copolymer of styrene and n‐butyl acrylate with composition of around 55 wt % styrene were investigated by comparing with their block copolymer counterparts. Compared with their block copolymer counterparts, the gradient copolymers showed lower elastic modulus, much larger elongation at break, and similar ultimate tensile strength at room temperature. This performance could be ascribed to that the local moduli continuously change from the hardest nanodomains to the softest nanodomains in the gradient copolymer, which alleviates the stress concentration during tensile test. Compared with the V‐shaped gradient (VG) copolymer, the linear gradient copolymer showed much higher elastic modulus but lower elongation at break. The mechanical properties of the gradient copolymers were more sensitive to the change in temperature from 9 °C to 75 °C. With recovery temperature increased from 10 °C to 60 °C, the strain recovery of VG copolymer would change steadily from 40% to 99%. However, the elastic recovery of linear and triblock copolymer was poor even at 60 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 860–868     

Block copolymer compatibilizers for polystyrene/poly(dimethylsiloxane) blends

Symmetric polystyrene (PS)–poly(dimethylsiloxane) (PDMS) diblock copolymers were mixed into a 20% dispersion of PDMS in PS. The effect of adding the block copolymer on the blend morphology was examined as a function of the block copolymer molecular weight (M_n,bcp), concentration, and viscosity ratio (η_r). When blended together with the PS and PDMS homopolymers, most of the block copolymer appeared as micelles in the PS matrix. Even when the copolymer was preblended into the PDMS dispersed phase, block copolymer micelles in the PS matrix phase were observed with transmission electron microscopy after mixing. Adding 16 kg/mol PS–PDMS block copolymer dramatically reduced the PDMS particle size, but the morphology, as examined by scanning electron microscopy, was unstable upon thermal annealing. Adding 156 kg/mol block copolymer yielded particle sizes similar to those of blends with 40 or 83 kg/mol block copolymers, but only blends with 83 kg/mol block copolymer were stable after annealing. For a given value of M_n,bcp, a minimum PDMS particle size was observed when η_r ～ 1. When η_r = 2.6, thermally stable, submicrometer particles as small as 0.6 μm were observed after the addition of only 3% PS–PDMS diblock (number‐average molecular weight = 83 kg/mol) to the blend. As little as 1% 83 kg/mol block copolymer was sufficient to stabilize a 20% dispersion of 1.1‐μm PDMS particles in PS. Droplet size reduction was attributed to the prevention of coalescence caused by small amounts of block copolymer at the interface. The conditions under which block copolymer interfacial adsorption and interpenetration were facilitated were explained with Leibler's brush theory. © 2002 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 346–357, 2002; DOI 10.1002/polb.10098     

Rheological characterization and microphase‐separated structure of a poly(ether‐block‐amide) segmented block copolymer

Melt of a segmented block copolymer having poly(lauryl lactam) as the hard segment and poly(tetramethylene oxide) as the soft segment was investigated by rheological techniques. Storage modulus of the polymer melt exhibits the nonterminal behavior resembling those of diblock and triblock copolymer melts, indicating the existence of a microphase‐separated structure. Contrary to block copolymers, the melt of the segmented block copolymer changes from a weak structure to a stiff one upon raising temperature. The storage modulus of the weak structure at low temperatures is inert to large‐amplitude oscillatory shear, while the oscillatory shear destroys the stiff structure at high temperatures and reduces its storage modulus to a value that is same as that of the weak structure. The tapping‐mode data of atomic force microscopy reveal that at low temperatures the polymer melt exhibits a biphasic structure consisted of small spherical soft domains dispersed in a slightly harder matrix; and at high temperatures the spherical domain structure preserves, though the domain coarsens and the hardness difference between the domain and the matrix enlarges. Infrared spectrum analysis shows that the temperature‐induced structural change is related to the dissociation of hydrogen bonding between the hard and soft segments. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2557–2567, 2005     

Microcalorimetric Investigation on the lower critical solution temperature behavior of N-isopropycrylamide-co-acrylic acid copolymer in aqueous solution

The lower critical solution temperature (LCST) behaviors of random and segmented copolymers of N-isopropylacrylamide (NIPAM) and acrylic acid (AA) prepared in dioxane and water have been investigated by using ultrasensitive microcalorimetry (US-DSC). The introduction of AA increases the LCST of the former but slightly affects that of the latter. When the molar fraction of AA is low (approximately 2 mol %), the LCST of the segmented copolymer shifts to a higher temperature with increasing pH, while the LCST of the corresponding random copolymer slightly changes. Below the boiling point of water, the random copolymer and segmented copolymer with the molar fraction of AA about 15 mol % no longer exhibit an LCST at pH > 5. The addition of calcium ions leads the LCST of both the segmented copolymer and random copolymer to decrease. Our results suggest that the LCST behavior of the copolymers is determined by the clustering of poly(N-isopropylacrylamide) segments.     

Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.     

Synthesis and thermal,mechanical, and optical properties of A–B–A or A–B block copolymers containing poly(norbornene‐co‐1‐octene)

A–B–A block copolymers which consist of poly(norbornene‐co‐1‐octene) and atactic polypropylene (PP) segments were synthesized by using ansa‐fluorenylamidotitanium complex as a catalyst varying the ratio of norbornene, 1‐octene, and propylene. The copolymer was obtained quantitatively with high molecular weight (>100,000) and narrow molecular weight distribution (polydispersity index, <1.5). A–B block copolymers of poly(norbornene‐co‐1‐octene) and poly(methyl methacrylate) (PMMA) was also obtained by the same procedure. Mechanical and optical properties of these copolymer films, which were obtained by solution casting process, were also investigated. Introduction of PP soft segment greatly improved mechanical properties, keeping their high transparency. Introduction of PMMA block also increased the tensile strength. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 267–271     

Block Index for Characterizing Olefin Block Copolymers

Summary: Olefin block copolymers produced by chain shuttling catalysis exhibit crystallinity characteristics that are distinct from what would be expected for typical random olefin copolymers with comparable monomer compositions produced from either ‘single-site’ or heterogeneous catalysis. Olefin block copolymers produced by chain shuttling catalysis have a statistical multiblock architecture. A unique structural feature of olefin-based block copolymers is that the intra-chain distribution of comonomer is segmented (statistically non-random). Fractionating an olefin block copolymer by preparative temperature rising elution fractionation, TREF, results in fractions that have much higher comonomer content than comparable fractions of a random copolymer collected at an equivalent TREF elution temperature. We have developed a “block index” methodology which quantifies the deviation from the expected monomer composition versus the analytical temperature rising elution fractionation, ATREF, elution temperature. When interpreted properly, this index indicates the degree to which the intra-chain comonomer distribution is segmented or blocked. The unique crystallization behavior of block copolymers determine the magnitude of the block index values because the highly crystalline segments along an otherwise non-crystalline chain tend to dominate the ATREF (and DSC) temperature distributions.     

Synthesis and properties of new block copolymers based on polydimethylsiloxane and tetraphenylethylene-containing polyimide

New polydimethylsiloxane (PDMS)-polyimide block copolymers were synthesized by the solution polycondensation of aminopropyl-terminated polydimethylsiloxane, 1,1-bis(4-aminophenyl)-2,2-diphenylethylene, and 3,3′,4,4′-benzophenonetetracarboxylic dithioanhydride in pyridine. New 1,3-bis(3-aminopropyl)tetramethyldisiloxane (BADS)-based random copolyimides were also prepared. The inherent viscosities of all the random and block copolyimides were in the range of 0.13–0.90 dL/g in N-methyl-2-pyrrolidone. These copolymers were soluble in N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol. All the BADS-based random copolymers and PDMS-containing copolymers with PDMS content above 42 wt % were soluble in tetrahydrofuran and chloroform. Transparent or somewhat cpaque films were prepared by casting from the reaction solutions. The BADS-based random copolyimides had one glass transition temperature (T_g) in the whole composition ranges, which showed single phase nature of the copolymers. On the other hand, the PDMS-polyimide block copolymers had double T_gS, indicating phase-separated morphology. The block copolymers containing PDMS content above 73 wt % behaved like a high temperature elastomer. © 1993 John Wiley & Sons, Inc.     

Block copolymers as compatibilizers for blends of linear low density polyethylene and polystyrene

Compatibilization of blends of linear low-density polyethylene (LLDPE) and polystyrene (PS) with block copolymers of styrene (S) and butadiene (B) or hydrogenated butadiene (EB) has been studied. The morphology of the LLDPE/PS (50/50) composition typically with 5% copolymer was characterized primarily by scanning electron microscopy (SEM). The SEB and SEBS copolymers were effective in reducing the PS domain size, while the SB and SBS copolymers were less effective. The noncrystalline copolymers lowered the tensile modulus of the blend by as much as 50%. Modulus calculations based on a coreshell model, with the rubbery copolymer coating the PS particle, predicted that 50% of the rubbery SEBS copolymer was located at the interface compared to only 5–15% of the SB and SBS copolymers. The modulus of blends compatibilized with crystalline, nonrubbery SEB and SEBS copolymers approached Hashin's upper modulus bound. An interconnected interface model was proposed in which the blocks selectively penetrated the LLDPE and PS phases to provide good adhesion and improved stress and strain transfer between the phases. © 1995 John Wiley & Sons, Inc.     

Nanostructured thermoset epoxy resin templated by an amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) diblock copolymer

An amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) (PEO–PDMS) diblock copolymer was used to template a bisphenol A type epoxy resin (ER); nanostructured thermoset blends of ER and PEO–PDMS were prepared with 4,4′‐methylenedianiline (MDA) as the curing agent. The phase behavior, crystallization, hydrogen‐bonding interactions, and nanoscale structures were investigated with differential scanning calorimetry, Fourier transform infrared spectroscopy, transmission electron microscopy, and small‐angle X‐ray scattering. The uncured ER was miscible with the poly(ethylene oxide) block of PEO–PDMS, and the uncured blends were not macroscopically phase‐separated. Macroscopic phase separation took place in the MDA‐cured ER/PEO–PDMS blends containing 60–80 wt % PEO–PDMS diblock copolymer. However, the composition‐dependent nanostructures were formed in the cured blends with 10–50 wt % PEO–PDMS, which did not show macroscopic phase separation. The poly(dimethylsiloxane) microdomains with sizes of 10–20 nm were dispersed in a continuous ER‐rich phase; the average distance between the neighboring microdomains was in the range of 20–50 nm. The miscibility between the cured ER and the poly(ethylene oxide) block of PEO–PDMS was ascribed to the favorable hydrogen‐bonding interaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3042–3052, 2006     

聚芳醚腈-聚硅氧烷嵌段共聚物的合成

采用4-烯丙基-2-甲氧基苯酚(Eugenol)为端基的聚二甲基硅氧烷与氟代苯端基含杂萘联苯结构聚芳醚腈,以碳酸钾为催化剂,二甲基亚砜与邻二氯苯为溶剂的条件下进行芳香亲核取代反应(SNAr),合成了一种高分子量的聚芳醚腈-聚硅氧烷嵌段共聚物,并采用FTIR和1H-NMR对该产物的结构进行了表征.DSC测试结果表明该类嵌段共聚物具有两个玻璃化转变温度(Tg),分别为-98～-90℃和255～287℃,而且共聚物具有优良的耐热性,10%的热失重温度(Td)在450℃以上.采用原子力显微镜和透射电镜观测发现该共聚物存在明显的相分离特征.     

Hydrogen bonding interactions,crystallization, and surface hydrophobicity in nanostructured epoxy/block copolymer blends

Hydrogen bonding interactions, phase behavior, crystallization, and surface hydrophobicity in nanostructured blend of bisphenol A‐type epoxy resin (ER), for example, diglycidyl ether of bisphenol A (DGEBA) and poly(ε‐caprolactone)‐block‐poly(dimethyl siloxane)‐block‐poly(ε‐caprolactone) (PCL–PDMS–PCL) triblock copolymer were investigated by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, transmission electron microscopy, small‐angle X‐ray scattering, and contact angle measurements. The PCL–PDMS–PCL triblock copolymer consisted of two epoxy‐miscible PCL blocks and an epoxy‐immiscible PDMS block. The cured ER/PCL–PDMS–PCL blends showed composition‐dependent nanostructures from spherical and worm‐like microdomains to lamellar morphology. FTIR study revealed the existence of hydrogen bonding interactions between the PCL blocks and the cured epoxy, which was responsible for their miscibility. The overall crystallization rate of the PCL blocks in the blend decreased remarkably with increasing ER content, whereas the melting point was slightly depressed in the blends. The surface hydrophobicity of the cured ER increased upon addition of the block copolymer, whereas the surface free energy (γ_s) values decreased with increasing block copolymer concentration. The hydrophilicity of the epoxy could be reduced through blending with the PCL–PDMS–PCL block copolymer that contained a hydrophobic PDMS block. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 790–800, 2010     

Synthesis of poly(arylene ether sulfone)‐block‐sulfonated polybutadiene: the selective post‐sulfonation of block copolymers as proton exchange membranes

A series of poly(arylene ether sulfone)‐block‐sulfonated polybutadiene (PAES‐b‐sPB) with different ion exchange capacities (IECs) were synthesized and evaluated as proton exchange membranes (PEMs) for possible applications in fuel cells. These sulfonated block copolymers were synthesized via condensation reaction between modified PAES and PB prepolymers, followed by selective post‐sulfonation of PB blocks using acetyl sulfate as the sulfonating reagent. The sulfonic groups were only attached onto PB blocks due to the high reactivity of double bonds to acetyl sulfate. The success of synthesis and selective post‐sulfonation were all confirmed by the Fourier transform infrared (FT‐IR) and nuclear magnetic resonance (NMR) spectra. PAES‐b‐sPB had good film‐forming ability and thermal stability. Mechanical properties of membranes varied with the sulfonation. The presence of sulfonic groups increased the tensile strength and Young's modulus but decreased the elongation at break. Transmission electron microscopy (TEM) images showed large ionic aggregates in membranes. Phase separation as well as the interconnected sulfonate groups which only localized on flexible PB blocks led to these ionic domains. The proton conductivity increased with the increasing IEC and temperature. With relatively low IEC, most membranes still exhibited sufficient proton conductivity. The above results indicated this strategy could be a prospective choice to prepare novel PEMs. Copyright © 2010 John Wiley & Sons, Ltd.