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In this study, dilute Nafion solutions consisting of solvents with various dielectric constants ɛ and solubility parameters δ, i.e. N,N′-dimethyl acetamide, N,N′-dimethyl formamide, N-methyl formamide, methanol–water mixture (4/1g/g), ethanol–water mixture (4/1g/g), and isopropanol–water mixture (4/1g/g), were freeze dried and the conformations of Nafion molecules in dilute solutions were observed...
Using dynamic light scattering (DLS) and capillary dynamic viscoelasticity (DVE) analyzer, we investigated dilute (0.5mg/ml) poly(diallyl dimethyl ammonium chloride) (PDADMAC) aqueous solution properties for three different molecular weights of PDADMACs mixed with various concentrations of NaCl. The dependence of PDADMAC molecular chain conformations in aqueous solutions on polymer molecular weight...
Poly(vinyl alcohol)–borate (PVA–borate) aqueous solutions properties with PVA concentrations ranging from 2 to 60g/L and borax concentrations of 0.0 and 0.2M were investigated at room temperature using static and dynamic light scattering (SLS and DLS), and dynamic viscoelasticity measurements. Light scattering and viscoelasticity data revealed that all the PVA–borate aqueous systems, except those...
The physical properties of 5wt% poly(NIPAM) (M v =3.22x10 5 ) semi-dilute solutions in H 2 O, D 2 O, and THF (tetrahydrofuran) solvents were studied using dynamic light scattering (DLS) and dynamic shear viscosity (DSV) measurements. The DLS data showed that there were poly(NIPAM) slow mode inter-polymer chains associations in H 2 O and D 2 O solvents...
Dilute solution properties of Nafion in methanol/water (4/1 wt ratio) mixture solvent with Nafion concentrations ranging from 0.2 to 9.0 mg/ml was studied using membrane osmometer, viscoelasticity analyzer, and dynamic light scattering. Two aggregation processes were observed. The primary aggregation process causes formation of smaller sizes (~10 3 nm) rod-like aggregation particles, which...
A poly(bisphenol A octane ether) (BA-C8) was synthesized. The isothermal spherulitic growth process was studied in situ using atomic force microscopy (AFM) at room temperature. For spherulites formed by homogeneous nucleation, the growth process includes the birth of a primary nucleus, the development of a founding lamella and the growth of the founding lamella into a spherulite. An embryo below a...
Two thermotropic copolyesters with inherent rigid spirobicromane (SPI) moieties were prepared to evaluate their registry effects of neighboring chains in the mesomorphic state. Due to this chain registry effect, copolyester I-19, synthesized from polycondensation of terephthaloyl bis(4-oxybenzoyl chloride) (TOBC), heptanediol (HD, 90mol%), and SPI (10mol%) exhibited different thermal behavior between...
A thermotropic copolyester I-19 prepared from a rigid, bent spirobicromane (SPI), 1,7-heptanediol (HD), and an aromatic ester triad, TOBC (terephthaloyl bis(4-oxybenzoyl chloride), was prepared and its thermal behavior investigated by differential scanning calorimetry. Copolyester I-19 exhibited completely different DSC thermograms between samples cooled from the isotropic liquid and the mesomorphic...
Poly(vinyl alcohol) (PVAL)/poly(N-vinyl-2-pyrrolidone) (PVP) blends were studied by differential scanning calorimetry (d.s.c.), Fourier transform infrared spectroscopy (FTi.r.), and X-ray photoelectron spectroscopy (XPS). A single glass transition temperature (T g ) was observed for all PVAL/PVP blends, suggesting that PVAL/PVP blends are miscible within the compositions considered. The specific...
The modification of novel trifunctional epoxy resins with silicon rubber to reduce stress while maintaining a high glass transition temperature is described. Trifunctional epoxy resins were synthesized from the condensation of 4-hydroxybenzaldehyde, chloroacetaldehyde or crotonaldehyde with phenol, followed by epoxidation with a halohydrin. The structure of the synthesized triphenols was characterized...
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