Dynamic light-scattering characterization of the molecular weight distribution of a broadly distributed phenolphthalein poly(aryl ether ketone)

Using a recently developed laser light-scattering (LLS) procedure, we accomplished the characterization of a broadly distributed unfractionated phenolphthalein poly(aryl ether ketone) (PEK-C) in CHCl3 at 25 degrees C. The laplace inversion of precisely measured intensity-intensity time correlation function from dynamic LLS leads us first to an estimate of the characteristic line-width distribution G(Gamma) and then to the translational diffusion coefficient distribution G(D). By using a previously established calibration of D (cm(2)/s) = 2.37 X 10(-4)M(-0.57), were able to convert G(D) into a differential weight distribution f(w)(M). The weight-average molecular weight M(w) calculated from f(w)(M) agrees well with that directly measured in static LLS. Our results indicate that both the calibration and LLS procedure used in this study are ready to be applied as a routine method for the characterization of the molecular weight distribution of PEK-C. (C) 1996 John Wiley & Sons, Inc.

Miscibility and crystallization behaviour of poly(ether ether ketone)/polyimide blends

The miscibility and crystallization behaviour of the blends of poly(ether ether ketone) (PEEK) with two thermoplastic polyimides (PI), PEI-E and YS-30, prepared by solution blending were studied by the use of small-angle X-ray scattering (SAXS), differential scanning calorimetry (d.s.c.) and polarizing microscopy techniques. The results obtained show that PEEK/YS-30 is miscible, while PEEK/PEI-E is partially miscible only in the composition range with PEI-E content up to 20 wt%. The crystallization behaviour of PEEK in PEEK/PI blends depends on the crystallization condition of the blend sample as well as the chemical structure and the content of the PI added. Our SAXS results indicate that the segregation of PI molecular chains during crystallization of PEEK chains in the blends is interfibrillar for PEEK/PEI-E blends, but interlamellar for PEEK/YS-30 blends. The compatibility and the crystallization behaviour are discussed in terms of charge transfer interaction between PI and PI molecules and between PI and PEEK molecules.

Laser light-scattering study of novel thermoplastics .2. Phenolphthalein poly(ether sulfone) (PES-C)

Five narrowly distributed fractions of phenolphthalein poly(ether sulfone) (PES-C) were studied in CHCl3 by both static and dynamic laser light scattering (LLS) at 25 degrees C. The dynamic LLS showed that the PES-C samples contain some large polymer clusters as in previously studied phenolphthalein poly(ether ketone)(PEK-C). These large clusters can be removed by a 0.1-mu m filter. Our results showed that [R(g)(2)](1/2)(z) = (3.35 +/- 0.13) x 10(-2) M(w)((0.52 +/- 0.03)) and [D] = (2.26 +/- 0.02) x 10(-4)M(w)-((0.54) +/- 0.03)) with [R(g)(2)](1/2)(z), M(w) and [D] being the z-average radius of gyration, the weight-average molecular weight, and the z-average translational diffusion coefficient, respectively. A combination of static and dynamic LLS results enabled us to determine D = (2.45 +/- 0.04) x 10(-4)M-((0.55 +/- 0.05)), where D and M correspond to monodisperse species. Using this scaling relationship, we have successfully converted the translational diffusion coefficient distribution into the molecular weight distribution for each of the five PES-C fractional The weight-average molecular weights obtained from dynamic light scattering have a good agreement with that obtained from static laser light-scattering measurements.

Local chain motions in a dilute solution of phenolphthalein poly(ether sulfone)

C-13 and H-1 relaxation times were measured as a function of temperature in two magnetic fields for dilute solutions of phenolphthalein poly(ether sulfone) (PES-C) in deuterated chloroform. The spin-lattice relaxation times were interpreted in terms of segmental motion characterized by the sharp cutoff model of Jones and Stockmayer (J. S. model). The phenyl group rotation is treated as a stochastic diffusion by the J. S. model. The restricted butterfly motion of the phenyl group attached to the cardo ring in PES-C is mentioned but is not discussed in detail in this work. Correlation times for the segmental motion are in the picosecond range which indicates the high flexibility of PES-C chains. The correlation time for the phenyl group internal rotation is similar to that of the segmental motion. The temperature dependence of these motions is weak. The apparent activation energy of the motions considered is less than 10 kJ/mol. The simulating results for PES are also reasonable considering the differences in structure compared with PES-C. The correlation times and the apparent activation energy obtained using the J. S. model for the main chain motion of PES-C are the same as those obtained using the damped orientational diffusion model and the conformational jump model.

Miscibility and phase behavior in blends containing random copolymers of poly(ether ether ketone) and phenolphthalein poly(ether ether ketone)

The miscibility and phase behavior of polysulfone (PSF) and poly(hydroxyether of bisphenol A) (phenoxy) with a series of copoly(ether ether ketone) (COPEEK), a random copolymer of poly(ether ether ketone) (PEEK), and phenolphthalein poly(ether ether ketone) (PEK-C) was studied using differential scanning calorimetry. A COPEEK copolymer containing 6 mol % ether ether ketone (EEK) repeat units is miscible with PSF, whereas copolymers containing 12 mol % EEK and more are not. COPEEK copolymers containing 6 and 12 mol % EEK are completely miscible with phenoxy, but those containing 24 mol % EEK and more are immiscible with phenoxy. Moreover, a copolymer containing 17 mol % EEK is partially miscible with phenoxy; the blends show two transitions in the midcomposition region and single transitions at either extreme. Two T(g)s were observed for the 50/50 blend of phenoxy with the copolymer containing 17 mol % EEK, whereas a single composition-dependent T-g appeared for all the other compositions. An FTIR study revealed that there exist hydrogen-bonding interactions between phenoxy and the copolymers. The strengths of the hydrogen-bonding interactions in the blends of the COPEEK copolymers containing 6 and 12 mol % EEK are the same as that in the phenoxy/PEK-C blend. However, for the blends of copolymers containing 17, 24, and 28 mol % EEK, the hydrogen-bonding interactions become increasingly unfavorable and the self-association of the hydroxyl groups of phenoxy is preferable as the content of EEK units in the copolymer increases. The observed miscibility was interpreted qualitatively in terms of the mean-field approach. (C) 1996 John Wiley & Sons, Inc.

Laser light-scattering study of novel thermoplastics .1. Phenolphthalein poly(aryl ether ketone)

Five different molecular weight phenolphthalein poly(aryl ether ketone) (PEK-C) fractions in CHCl3 were studied by static and dynamic laser light scattering(LLS). The dynamic LLS revealed that the PEK-C samples contain some large polymer clusters. These large clusters can be removed by filtering the solution with a 0.1-mu m filter. We found that the persistence length of PEK-C in CHCl3 at 25 degrees C is similar to 2 nm and the Flory characteristic ratio, C-infinity is similar to 25. Our results showed that [R(g)(2)](1/2)(z) = (3.50+/-0.20) x 10(-2)M(w)(0.54+/-0.01) and [D] = (2.37+/-0.05) x 10(-4)M(w)(-0.55+/-0.01), with [R(g)(2)](1/2)(z), M(w), and [D] being the z-average radius of gyration, the weight-average molecular weight, and the z-average translational diffusion coefficient, respectively. A combination of static and dynamic LLS results enabled us to determine D = (2.20+/-0.10) x 10(-4)M(-0.555+/-0.015), where D and M correspond to monodisperse species. Using this calibration between D and M,we have determined molecular weight distributions of five PEK-C fractions from their corresponding translational diffusion coefficient distribution.

Structural study on poly(ether ether ketone ketone)-poly(ether biphenyl ether ketone ketone) copolymers

Structures of poly(ether ether ketone ketone)-poly(ether biphenyl ether ketone ketone) copolymers were studied by using small angle X-ray scattering and the one-dimensional electron density correlation function method. The results revealed that structures of the aggregated state of the copolymers depend closely on the biphenyl content (n(b)). When n(b) = 0.35, invariant Q, long period L, average thickness of crystal lamellae (d) over bar, electron density difference eta(c) - eta(a) and degree of crystallinity W-c,W-x assume minimum values.

Enhanced glass fiber-reinforced phenolphthalein poly(ether ketone) composites by blending poly(phenylene sulfide)

The mechanical properties of glass fiber-reinforced phenolphthalein poly(ether ketone)/poly(phenylene sulfide) (PEK-C/PPS) composites have been studied. The morphologies of fracture surfaces were observed by scanning electron microscope. Blending a semicrystalline component, PPS, can improve markedly the mechanical properties of glass fiber-reinforced PEK-C composites. These results can be attributed to the improvement of fiber/matrix interfacial adhesion and higher fiber aspect ratio. (C) 1996 John Wiley & Sons, Inc.

Synthesis and properties of block copolymers of poly(ether sulphone)s with liquid crystalline polyester units

Block copolymers of poly(ethersulphone) (PES) oligomers with liquid crystalline polyester units were synthesized by the reaction of dihydroxy-terminated poly(ether sulphone) oligomers (number-average molecular weights: 704, 1,158 and 2570) and terephthaloyl bis(4-oxybenzoyl chloride), and their properties were investigated. The results indicated that the copolymer with PES segments of molecular weight of 704 possessed birefringent features when annealed at 360 degrees C, while the copolymer with PES segments of molecular weight of 2,570 became isotropic. Also, the block copolymers had a better chemical resistance and high-temperature stability than PES.

Synthesis and characterization of thermotropic copolyesters and copoly(ester-amide)s containing oxyethylene-ether as the spacer

Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly (ester-amide)s to reduce the melting point of resulting polymers. The melting point was greatly reduced to 200 degrees C or even lower in some cases, and the molecular weight was satisfactorily high as reflected by inherent viscosity. The polymers exhibited high thermal stability and good mechanical properties as determined by TGA and mechanical tests. The copolyester showed better crystallinity and liquid crystallinity than corresponding copoly (ester-amide)s with similar monomer composition as reflected by POM observation and WAXD study. The melting points for both copolyesters and copoly (ester-amide)s showed great dependence on the p-acetoxybenzoic acid (PAB) content in monomer composition and reached the lowest value when PAB was 29 mol%.

SYNTHESIS AND CHARACTERIZATION OF A NEW COMB-LIKE POLYMER-BASED ON POLY(VINYL METHYL ETHER-ALT-MALEIC ANHYDRIDE) BACKBONE

A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.

MORPHOLOGY AND DYNAMIC-MECHANICAL PROPERTIES OF NYLON 66/POLY(ETHER IMIDE) BLENDS

The morphology and dynamic mechanical properties of blends of poly(ether imide) (PEI) and nylon 66 over the full composition range have been investigated. Torque changes during mixing were also measured. Lower torque values than those calculated by the log-additivity rule were obtained, resulting from the slip at the interface due to low interaction between the components. The particle size of the dispersed phase and morphology of the blends were examined by scanning electron microscopy. The composition of each phase was calculated. The blends of PEI and nylon 66 showed phase-separated structures with small spherical domains of 0.3 similar to 0.7 mu m. The glass transition temperatures (T(g)s) of the blends were shifted inward, compared with those of the homopolymers, which implied that the blends were partially miscible over a range of compositions. T-g1, corresponding to PEI-rich phase, was less affected by composition than T-g2, corresponding to nylon 66-rich phase. This indicated that the fraction of PEI mixed into nylon 66-rich phase increased with decreasing PEI content and that nylon 66 was rarely mixed into the PEI-rich phase. The effect of composition on the secondary relaxations was examined. Both T-beta, corresponding to the motion of amide groups in nylon 66, and T-gamma, corresponding to that of ether groups in PEI, were shifted to higher temperature, probably because of the formation of intermolecular interactions between the components.

SIMPLE-MODELS FOR STRESS-RELAXATION AND YIELD PHENOMENON OF PHENOLPHTHALEIN POLY(ETHER KETONE)

According to stress relaxation curves of phenolphthalein poly(ether ketone) (PEK-C) at different temperatures and the principle of time-temperature equivalence, the master curves of PEK-C at arbitrary reference temperatures are obtained. A coupling model (Kohlrausch-Williams-Watts) is applied to explain quantitatively the different temperature dependence of stress relaxation behavior and the relationship between stress relaxation and yield phenomenon is established through the coupling model.

THE IZOD IMPACT FRACTURE-BEHAVIOR OF PHENOLPHTHALEIN POLY(ETHER KETONE)

The Izod impact fracture behaviour of notched specimens of phenolphthalein poly(ether ketone) (PEK-C) has been studied over a temperature range from room temperature to 240 degrees C by using an instrumented impact tester. The temperature dependence of the maximum load, total impact energy, initiation energy, propagation energy, ductility index (DI) and the relationships between these parameters and the relaxation processes have been investigated.

VISCOELASTIC PROPERTIES OF PHENOLPHTHALEIN POLY(ETHER KETONE)

Stress relaxation and dynamic mechanical behavior of phenolphthalein poly(ether ketone) (PEK-C) have been investigated. Using Ferry's reduction method, the master curve was obtained. From the experimental results, we found that the WLF equation is not appropriate in the lower-temperature range (T < T-g). The relaxation spectrum was calculated according to the first approximation method proposed by Schwarzl and Staverman. In addition to the alpha-transition region, a second transition zone is revealed at low temperature. This transition is probably due to a restricted motion of its main chain. (C) 1995 John Wiley and Sons, Inc.