Synthesis of high molecular weight sulfonated poly(arylene ether sulfone) copolymer without azeotropic reaction

2015 ◽  
Vol 275 ◽  
pp. 92-96 ◽  
Author(s):  
So Young Lee ◽  
Yeonhye Kwon ◽  
Bo Hyun Kim ◽  
Jieon Chae ◽  
Jong Hyun Jang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Arylene Ether ◽  
Sulfonated Poly

Preparation and characterization of poly(arylene ether isoxazole)s by fluoride ion-mediated aromatic nucleophilic displacement reactions

1994 ◽  
Vol 6 (4) ◽  
pp. 303-319 ◽  
Author(s):  
C G Herbert ◽  
R G Bass
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
High Performance ◽  
Weight Control ◽  
Side Reaction ◽  
Polymer Chains ◽  
Fluoride Ion ◽  
Silyl Ether ◽  
Good Thermal Stability ◽  
Arylene Ether

As part of a continuing effort to prepare novel thermally stable high-performance polymers, poly(arylene ether isoxazole)s have been prepared by fluoride ion-catalysed aromatic nucleophilic substitution reactions with bis(trimethylsiloxyphenyl) isoxazoles and activated bisarylhalides in diphenyl sulphone. Initial investigations involving the preparation of these materials with isoxazole bisphenols and activated bisarylhalides in the presence of potassium carbonate indicated that, under reaction conditions necessary to prepare high-molecular-weight materials, the isoxazole monomer was converted to an enamino ketone. This side reaction was avoided by using fluoride as a base. However, trimethylsilyt ether derivatives of the isoxazole bisphenols were required in these polymerizations for the preparation of high-molecular-weight materials. Moderate to high inherent viscosity (htAh: 0.43-0.87 dl g -) materials with good thermal stability (air: 409-477C, helium: 435-512C) can be prepared by the silyl ether method. Glass transition temperatures ranged from 182 to 225 C for polymers with phenyl pendants and from 170 to 214 C for those without. Molecular weight control by 2% endcapping and the incorporation of a phenyl pendant at the 4 position of the isoxazole is necessary to yield polymers soluble in polar aprotic solvents at room temperature. There is evidence, however, indicating the existence of crosslinks between the polymer chains when the silyl ether approach is utilized.

Poly(para-phenylene) ionomer membranes: effect of methyl and trifluoromethyl substituents

2021 ◽  
Author(s):  
Fanghua Liu ◽  
Jinju Ann ◽  
Junpei Miyake ◽  
Kenji Miyatake
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Main Chain ◽  
Polymer Main Chain ◽  
Ionomer Membranes ◽  
Sulfonated Poly

Sulfonated poly(para-phenylene)s with high molecular weight and membrane forming capability were obtained by use of the effect of methyl and trifluoromethyl substituents. The linearity of the polymer main chain decreased...

Synthesis of Sulfonated Poly(arylene ether sulfone)-b-Poly(arylene ether ketone) Copolymers for Proton Exchange Membrane Fuel Cell

2013 ◽  
Vol 798-799 ◽  
pp. 165-169
Author(s):  
Hai Dan Lin ◽  
Xiao Ying Yang ◽  
Cheng Xun Sun
Keyword(s):  
Molecular Weight ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Multiblock Copolymers ◽  
H Nmr ◽  
Arylene Ether ◽  
Transmission Electron ◽  
Ether Ketone ◽  
Exchange Membrane ◽  
Sulfonated Poly

A new series of hydrophobic-hydrophilic multiblock copolymers derived from fluorine terminated poly (arylene ether ketone) as hydrophobic blocks and phenoxide terminated sulfonated poly (arylene ether sulfone) as hydrophilic blocks were successfully synthesized and evaluated for use as proton exchange membranes (PEMs). All the hydrophobic and hydrophilic oligomers were synthesized via molecular-weight controlled step growth polymerization of the monomers. 1H NMR spectra were used as characterization tool to determine the telechelic oligomers molecular weight and multiblock copolymers structure. The morphologies of multiblock copolymers were investigated by transmission electron microscopy (TEM), which showed they had a clear microphase-separated structure between the hydrophilic domains and hydrophobic domains. All the sulfonated poly (arylene ether sulfone)-b-poly (arylene ether ketone) copolymers can easily be cast into tough membranes for applications in proton exchange membrane.

Microtubule motors and other maps

1990 ◽  
Vol 48 (3) ◽  
pp. 1-1
Author(s):  
Richard B. Vallee
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cytoplasmic Dynein ◽  
Organelle Transport ◽  
Structural Components ◽  
Microtubule Associated Proteins ◽  
Microtubule Motors ◽  
Associated Proteins ◽  
The Subject ◽  
Intracellular Motility

Microtubules are involved in a number of forms of intracellular motility, including mitosis and bidirectional organelle transport. Purified microtubules from brain and other sources contain tubulin and a diversity of microtubule associated proteins (MAPs). Some of the high molecular weight MAPs - MAP 1A, 1B, 2A, and 2B - are long, fibrous molecules that serve as structural components of the cytamatrix. Three MAPs have recently been identified that show microtubule activated ATPase activity and produce force in association with microtubules. These proteins - kinesin, cytoplasmic dynein, and dynamin - are referred to as cytoplasmic motors. The latter two will be the subject of this talk.Cytoplasmic dynein was first identified as one of the high molecular weight brain MAPs, MAP 1C. It was determined to be structurally equivalent to ciliary and flagellar dynein, and to produce force toward the minus ends of microtubules, opposite to kinesin.

Studies on the Functionality of Newly Synthesized Fibrinogen after Treatment of Acute Myocardial Infarction with Streptokinase, Increase in the Rate of Fibrinopeptide Release

1993 ◽  
Vol 70 (06) ◽  
pp. 0978-0983 ◽  
Author(s):  
Edelmiro Regano ◽  
Virtudes Vila ◽  
Justo Aznar ◽  
Victoria Lacueva ◽  
Vicenta Martinez ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Molecular Weight ◽  
Steady State ◽  
High Molecular Weight ◽  
Coronary Arteries ◽  
Risk Index ◽  
Weight Fraction ◽  
High Molecular Weight Fraction ◽  
Fibrinopeptide A

SummaryIn 15 patients with acute myocardial infarction who received 1,500,000 U of streptokinase, the gradual appearance of newly synthesized fibrinogen and the fibrinopeptide release during the first 35 h after SK treatment were evaluated. At 5 h the fibrinogen circulating in plasma was observed as the high molecular weight fraction (HMW-Fg). The concentration of HMW-Fg increased continuously, and at 20 h reached values higher than those obtained from normal plasma. HMW-Fg represented about 95% of the total fibrinogen during the first 35 h. The degree of phosphorylation of patient fibrinogen increased from 30% before treatment to 65% during the first 5 h, and then slowly declined to 50% at 35 h.The early rates of fibrinopeptide A (FPA) and phosphorylated fibrinopeptide A (FPAp) release are higher in patient fibrinogen than in isolated normal HMW-Fg and normal fibrinogen after thrombin addition. The early rate of fibrinopeptide B (FPB) release is the same for the three fibrinogen groups. However, the late rate of FPB release is higher in patient fibrinogen than in normal HMW-Fg and normal fibrinogen. Therefore, the newly synthesized fibrinogen clots faster than fibrinogen in the normal steady state.In two of the 15 patients who had occluded coronary arteries after SK treatment the HMW-Fg and FPAp levels increased as compared with the 13 patients who had patent coronary arteries.These results provide some support for the idea that an increased synthesis of fibrinogen in circulation may result in a procoagulant tendency. If this is so, the HMW-Fg and FPAp content may serve as a risk index for thrombosis.

Sign in / Sign up

Export Citation Format

Share Document