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An advanced analytic method, based mainly on thermorheological analysis of standard frequency sweeps at several temperatures, is introduced which can determine a host of rheological indicators for long-chain branched polyethylenes and other materials with an Arrhenius-type temperature dependence. The method can be used to classify and categorize unknown samples to material types (tubular and autoclave low density polyethylene, long-chain branched metallocene polyethylene). For long-chain branched metallocene polyethylenes, it is, furthermore, possible to determine molar mass and branching degree using established relations with rheological behavior. It is, therefore, possible to gain a rather comprehensive picture of the molecular structure of long-chain branched polyethylenes using only a relatively simple set of rheological experiments. An automated analysis routine facilitates the evaluation.

Summary: Impact poly(propylene) copolymers (IPC) having various ethylene-propylene rubber (EPR) compositions were prepared using a high activity Ziegler-Natta catalyst. EPR composition was characterized by temperature rising elution fractionation (TREF) analysis and FT-IR spectroscopy. Effect of EPR composition on the morphology and surface properties of IPC was investigated by scanning electron microscopy (SEM), 3D profiler, and gloss meter. Composition and amount of amorphous and crystalline EPR were quantified by TREF and found to be dependent on the ethylene content in EPR. From the SEM result, it was found EPR composition has a strong influence on its shape and size. IPCs containing propylene-rich EPR exhibited a finer dispersion of EPR phase. The surface roughness decreased with decreasing ethylene content in EPR. The comparison of EPR composition and morphology and surface properties exhibited strong correlations.

Sulfonated poly(ether ketone ketone) ionomers (SPEKK) with ion-exchange capacities (IEC) between 0.2 and 3.4 meq/g were prepared by sulfonating PEKK with a mixture of concentrated and fuming sulfuric acids. Sulfonation occurs only on the phenyl rings attached to ether and ketone groups. The glass transition temperature of the dry SPEKK ionomers increased linearly with increasing IEC, and the ionomers were thermally stable to 250°C, above which desulfonation occurred. Waterswollen ionomers exhibited microphase separated morphologies, and the average correlation length determined by small angle X-ray scattering increased with increasing IEC. The proton conductivity of hydrated SPEKK membranes measured by impedance spectroscopy ranged from 10 –3 to 10 –1 S/cm as the IEC increased from 1.0 to 2.4 meq/g. Single cell performance curves on membrane-electrode assemblies (MEA) indicated that the SPEKK membranes approached the performance of Nafion™ for an IEC of 2 meq/g. POLYM. ENG. SCI., 45:1081–1091, 2005. © 2005 Society of Plastics Engineers

The phase behavior and crystallization of poly(ether ketone ketone)/polyimide blends was investigated by differential scanning calorimetry and dynamic mechanical analysis, and chemical interactions in the blends were probed by Fourier-transform infrared spectroscopy. Amorphous blends were miscible over the entire range of composition, although mixing was most favorable at higher thermoplastic polyimide concentrations. Blending suppressed crystallization, especially of the minor component, but crystallization of both components, however, did occur in most of the blends. While blends quenched from the melt exhibited only a single amorphous phase, melt crystallized blends appeared to possess two amorphous phases with different compositions. Shifts in the vibration frequencies of the carbonyl and imide bonds were inconsistent with the development of strong, specific intermolecular interactions, but may be explained by a disruption of the packing of the two homopolymers by nature of the mixing. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1227–1235, 2004

The addition of a thermotropic liquid crystalline, wholly aromatic copolyester, TLCP, improved the melt processability of poly(ether ketone ketone), PEKK. The tensile strength and modulus of the blends also improved with increasing TLCP, but the elongation at break decreased significantly. The blends were phase-sepa- rated, but the polymers were partially miscible as evident from shifts of the glass transition temperature (Tg) of each component towards that of the other component in the blend. Similarly, the melting points (Tm) of both components were depressed by blending. When the crystallization temperature was above Tm of the TLCP, the PEKK crystallization rate in the blend was slower than for the pure material, while crystallization was faster when the temperature was below Tm of the TLCP. Polym. Eng. Sci. 44:541-547, 2004. © 2004 Society of Plastics Engineers.

The effect of physical aging above Tg on ionic aggregation in the zinc salt of sulfonated poly(ethylene-co-propylene-co-ethylidene norbornene) ionomer was investigated by differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and dynamic mechanical thermal analysis (DMTA). The time-dependent development of a high temperature DSC endotherm and a high temperature tan δ relaxation were attributed to the dynamics of microphase separation of ionic aggregates. That conclusion was confirmed by the concurrent growth of a SAXS peak corresponding to the ionic microphase. The aging process at 25 °C occurred over a period of about 1 month, even though the ionomer was ca. 70 °C above Tg, where segmental mobility of the polymer is expected to be high. The kinetics of aging were dependent on temperature; a maximum in the rate of ionic aggregate formation occurred between 10 and 45 °C.

Binary blends of the sulfonated poly(ether ether ketone) (SPEEK)–poly(ether imide) (PEI) and SPEEK–polycarbonate (PC), and ternary blends of the SPEEK–PEI–PC, were investigated by differential scanning calorimetry. SPEEK was obtained by sulfonation of poly(ether ether ketone) using 95% sulfuric acid. From the thermal analysis of the SPEEK–PEI blends, single glass transition temperature (Tg) was observed at all the blend composition. For the SPEEK–PC blends, double Tgs were observed. From the results of thermal analysis, it is suggested that the SPEEK–PEI blends are miscible and the SPEEK–PC blends are immiscible. Polymer–polymer interaction parameter (χ12) of the SPEEK–PEI blends was calculated from the modified Lu and Weiss equation, and found to range from −0.011 to −0.825 with the blend composition. For the SPEEK–PC blends, the χ12 values were calculated from the modified Flory–Huggins equation, and found to range from 0.191 to 0.272 with the blend composition. For the SPEEK–PEI–PC ternary blends, phase separation regions that showed two Tgs were found to be consistent with the spinodal curves calculated from the χ12 values of the three binary blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2488–2494, 2000

Crystallization behavior and rheological properties of blends of bisphenol-A polycarbonate (PC) and polypropylene (PP) prepared by screw extrusion have been investigated by differential scanning calorimetry (DSC), polarized-light microscopy, scanning electron microscopy, and a Rheometrics Mechanical Spectrometer. In the study of thermal analysis of PC-PP blends by DSC, double crystallization peaks were observed in the PC-rich compositions. In the study of spherulite of 7/3 PC-PP blend, large droplets (>25 μm) of PP were crystallized between 115°C and 105°C, and then small droplets (

The thermal properties of blends of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) prepared by screw extrusion were investigated by differential scanning calorimetry. From the thermal analysis of amorphous PEEK–PEI blends which were obtained by quenching in liquid nitrogen, a single glass transition temperature (Tg) and negative excess heat capacities of mixing were observed with the blend composition. These results indicate that there is a favorable interaction between the PEEK and PEI in the blends and that there is miscibility between the two components. From the Lu and Weiss equation and a modified equation from this work, the polymer–polymer interaction parameter (χ12) of the amorphous PEEK–PEI blends was calculated and found to range from −0.058 to −0.196 for the extruded blends with the compositions. The χ12 values calculated from this work appear to be lower than the χ12 values calculated from the Lu and Weiss equation. The χ12 values calculated from the Tg method both ways decreased with increase of the PEI weight fraction. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 733–739, 1999

Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone (PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and dynamic mechanical thermal analysis. From the measured glass transition temperature (Tg) and specific heat increment (ΔCp) at the Tg, it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase. From the DSC study of PSF-LCP and PAS-LCP blends, the Tg(PSF) and Tg(PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible with LCP. The polymer-polymer interaction parameter (χ12) and the degree of disorder (y/x1) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The χ12 values have been calculated from the Tg data and found to be 0.181 ± 0.004 at 593 K for the PEI-LCP blends and 0.069 ± 0.006 at 623 K for the PEEK-LCP blends. Using the previously presented method, the χ12 and y/x1 in partially miscible systems have been determined.