Characterization of Engineering Polymers by Dynamic Mechanical Analysis

Effects of physical aging on the submicroscopic structure and dynamic mechanical properties of amorphous poly(ether sulfone) copolymer film were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and electron‐microscopy measurements. Heat flow responses were measured after annealing the amorphous samples obtained, by quenching the melt into an ice‐water bath close to but below the glass transition temperature. The extent of aging is related to the supercooling from the glass transition temperature and to the aging time. The activation energy of the aging process was estimated by the Williams–Watt expression (Williams and Watts, Trans Faraday Soc 1970, 66, 80). A systematic study of the influence of aging on the dynamic mechanical properties of poly(ether sulfone) copolymer has also been made. During isothermal annealing, the increase of the temperature of tan δ peak for the α and β′ relaxation with aging time has been observed. The aging in the zone of the β peak has also been investigated and an interpretation of the results was proposed on the basis of foregone theories. The result of electron‐microscopy investigation indicates that poly(ether sulfone) copolymer has formed a local order structure during the physical aging. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 530–534, 2006

New segmented aromatic poly(ether sulfone)‐amide and poly(ether sulfone)‐imide copolymers were synthesized by the chain extension of α,w‐diamine‐terminated poly(ether sulfone) oligomer with both aromatic dicarboxylic acid chlorides and tetracarboxylic dianhydrides, respectively. Crystallization of the poly(ether sulfone)unit was suppressed by the introduction of amide or imide linkage along the polymer backbone, giving amorphous copolymers that were +eadily soluble in various organic solvents. The copolymers had somewhat higher glass transition temperatures than the parent poly(ether sulfone). They afforded transparent and tough films by solution casting. © 1992 John Wiley & Sons, Inc.

New poly(ether sulfone)–aramid block copolymers were synthesized from an α, ω‐diamineterminated poly(ether sulfone) oligomer, aromatic diamines, and aromatic dicarboxylic acid chlorides by the low‐temperature solution polycondensation in N‐methyl‐2‐pyrrolidone. By the introduction of aramid into the poly(ether sulfone), the glass transition temperatures of the block copolymers rose and the mechanical properties were significantly improved. Microphase separation, which often takes place in many block copolymers, did not occur in the present block copolymers. © 1993 John Wiley & Sons, Inc.

A facile and practical method for fabricating antifouling and antimicrobial poly(ether sulfone) (PES) membranes is developed in this work. A PES blend membrane was first fabricated by a traditional nonsolvent induced phase separation (NIPS) process with a reactive amphiphilic copolymer poly(ether sulfone)-block-poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA-b-PES-b-PDMAEMA) as the blending additive. The hydrophilic PDMAEMA chains in the copolymer additive spontaneously migrated toward the interfaces between membrane and coagulant bath (usually water) during membrane formation. The enriched PDMAEMA chains on the as-made blend membranes were then quaternized by reacting with 1,3-propane sultone (1,3-PS) and 1-bromodecane, respectively. The zwitterionic PES membranes obtained from 1,3-PS treatment showed significantly improved antifouling ability and hemocompatibility. In another case, the resulting cationic PES membranes treated with 1-bromodecane exhibited excellent antibacterial activities against Es...

Synthesis and properties of poly(ether ether ketone)-poly(ether sulfone) block copolymers

Blends of a poly(ether sulfone) (PES) and a polycarbonate (PC) were prepared by melt‐mixing and were studied by tensile tests, differential scanning calorimetry, dynamic mechanical analysis, density measurements and transmission electron microscopy (TEM). The blends were found to be two‐phase systems and an interfacial layer was presumed to be formed between two phases, which was verified by TEM. A synergism of elongation at break and tensile modulus was shown in PES/PC blends. The effects of the crosshead speed on the mechanical properties were discussed for blends with different PES/PC weight ratios.

Self-polycondensation of AB-type monomers is an advantageous route to produce high-molecular-weight polymers without considerable adjustment in the mole ratio of the functionalities. Furthermore, the resulting polymers incorporate two different functional groups at the chain ends that enable the preparation of AB- and ABC-type block copolymers. In this study, poly(ether sulfone)s (PESs) were prepared via self-polycondensation of four AB-type monomers. The reactivity of the AB-type monomers was systematically investigated through model reactions and nuclear magnetic resonance measurements, which suggested that the novel AB-type monomers, 4-chloro-4′-(hydroxyphenyloxy)diphenylsulfone (monomer C) and 4-fluoro-4′-(hydroxyphenyloxy)diphenylsulfone (monomer D), are highly susceptible to nucleophilic aromatic substitution (SNAr) reactions. High-molecular-weight PESs (Mw >110 000) were obtained via the self-polycondensation of monomers C and D. The resulting PESs exhibited excellent thermal properties comparable with PESs prepared from A2- and B2-type monomers. Self-polycondensation of four different AB-type monomers including two novel monomers (monomers C and D) were carried out in the presence of potassium carbonate. High-molecular-weight poly(ether sulfone)s (Mw >110 000) were obtained from monomers C and D.

Membrane formation by immersion precipitation has been investigated for two different polymer blends: poly(ether sulfone) / poly(vinyl pyrrolidone), a common blend for obtaining high performance UF or MF membranes, and poly(ether sulfone) / poly(styrene). The latter blend contains a polymer as additive that is not soluble in the precipitant used. It yields structures that confirm the fundamental basis of a model describing the formation of membranes from polymer blends. It appears that the membrane formation is dominated by the diffusional behaviour of the polymers relative to each other.A general classification of membrane structures from a polymer blend is presented; it is established that spinodal decomposition may well be responsible for the open porous structures usually found when using a polymer blend such as poly(ether sulfone) and poly(vinyl pyrrolidone).

Synthesis of novel crosslinked sulfonated poly(ether sulfone)s using bisazide and their properties for fuel cell application

Hydrophilic modification of poly(ether sulfone) ultrafiltration membrane surface by self-assembly of TiO 2 nanoparticles

Hybrid composites, based on poly(ether sulfone) (PES) and glass fiber–reinforced copolyester liquid crystalline polymer (gLCP) up to 40% gLCP, were obtained by injection molding: these polymers were immiscible. Despite its higher viscosity, the gLCP acted as a processing aid for PES. The Young's modulus of the composites increased linearly with gLCP content, attributed to the opposing effects of increasing skin thickness and decreasing orientation of the fibrillated LCP in the skin. The break properties decreased with increasing gLCP content, mainly because of the lack of adhesion between the phases. The notched impact strength increased substantially on addition of 10% gLCP, suggesting that the dispersed rigid particles changed the fracture behavior of PES. The composite with 10% gLCP appeared to be the most attractive because it showed an increase in stiffness of 18%, 6.5‐fold impact strength, and a tensile strength similar to that of PES. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 854–860, 2004

ABSTRACTThe segmental dynamics of functional graphene (fGR)/poly(ether sulfone ether ketone ketone) (PESEKK) nanocomposites were investigated via differential scanning calorimetry and dynamic mechanical analysis (DMA) measurements. First, fGR was prepared using graphene oxide and sodium dodecylbenzene sulfonate. Subsequently, a series of fGR/PESEKK nanocomposites were prepared through solution blend. When the sulfone groups were introduced into the segments of PESEKK polymers, the glass transition temperature (Tg) of PESEKK was higher than that of free sulfone functionalized poly(ether ketone ketone). The fGR/PESEKK nanocomposites displayed a uniform nanostructure because of the strong interfacial interaction between fGR and PESEKK. With the increase in the fGR contents, the Tg values of fGR/PESEKK nanocomposites decreased. Two loss factor peaks were noted in the fGR/PESEKK nanocomposites, which were characterized via DMA. The α′‐relaxation of the nanocomposites at low temperature was assigned to polymer chains close to the polymer/filler interface with mobility higher than that in the bulk unfilled PESEKK (α‐relaxation). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44391.

Heavy metal remediation via poly(3,4-ethylene dioxythiophene) deposition onto neat and sulfonated nonwoven poly(ether sulfone)

A new blend ultrafiltration (UF)/nanofiltration (NF)-based proton-conductive membrane, which comprised poly(ether sulfone) (PES), sulfonated poly(ether ether ketone) (SPEEK) and absorbed aqueous acid, as an alternative to traditional exchange membrane, was proposed and designed for H2/Cl2 fuel cells. The effect of SPEEK concentration at different degree of sulfonation on membrane properties was systematically studied. The room-temperature conductivity of the prepared membrane doped with 3 M hydrochloric acid reached up to 106–131 mS cm−1. The electrochemical characteristics of membrane/electrode assemblies using the PES–SPEEK composite membrane were also analyzed. The cell exhibited better performance than that of a cell based on Nafion 212 membrane (about twice). The study provides an effective way to fabricate high performance porous membranes for H2/Cl2 fuel cell applications.

If the necessary infrastructure can be provided, a practical future electric vehicle will be an efficient hydrogen-powered hybrid operating on a polymer fuel cell. Light weight, lowest cost and high efficiency imply an atmospheric pressure, rather than a pressurized, system. Polymer fuel cells require humidification for ionic conductivity, which means that product water is normally rejected as liquid. Atmospheric pressure systems of this type are difficult to operate. A self-humidified atmospheric pressure system operating at higher temperature (about 75-80 °C) on oxygen-enriched air rejecting product water in the vapour phase is described. It combines the advantages of unpressurized operation with the higher power density of a pressurized system, but with much lower parasitic power requirements.