Compatibilization of blends of polystyrene and zinc salt of sulfonated polystyrene by poly(styrene-b-4-vinylpyridine) diblock copolymer

The compatibilizing effect and mechanism of poly(styrene-b-4-vinylpyridine) diblock copolymer, P(S-b-4VPy), on the immiscible blend of polystyrene (PS)/zinc salt of sulphonated polystyrene (Zn-SPS) were studied. SEM results show that the domains of the dispersed phase in the blend become finer. DSC experiments reveal that the difference between the two T-g's corresponding to the phases in the blends becomes larger on addition of P(S-b-4VPy), mainly resulting from dissolving of the poly(4-vinylpyridine (P4VPy) block in the Zn-SPS phase. FTIR analysis shows that compatibility of P4VPy and Zn-SPS arises from the stoichiometric coordination of the zinc ions of Zn-SPS and pyridine nitrogens of P4VPy. SAXS analysis indicates the effect of the P(S-b-4VPy) content on the structure of the compatibilized blends. When the content of the block copolymer is lower than 4.1 wt%, the number of ion pairs in an aggregate in the Zn-SPS becomes smaller, and aggregates in ionomer in the blend become less organized with increasing P(S-b-4VPy). When the P(S-b-4VPy) content in the blend is up to 7.4 wt%, a fraction of P(S-b-4VPy) form a separate domain in the blend. (C) 1999 Elsevier Science Ltd. All rights reserved.

Preparation of the HIPS/MA graft copolymer and its compatibilization in HIPS/PA1010 blends

The graft copolymer of high-impact polystyrene (HIPS) grafted with maleic anhydride (MA) (HIPS-g-MA) was prepared with melt mixing in the presence of a free-radical initiator. The grafting reaction was confirmed by infrared analyses, and the amount of MA grafted on HIPS was evaluated by a titration method. 1-5% of MA can be grafted on HIPS. HIPS-g-MA is miscible with HIPS. Its anhydride group can react with polyamide 1010 (PA1010) during melt mixing of the two components. The compatibility of HIPS-g-MA. in the HIPS/PA1010 blends was evident. Evidence of reactions in the blends was confirmed in the morphology and mechanical behavior of the blends. A significant reduction in domain size was observed because of the compatibilization of HIPS-g-MA in the blends of HIPS and PA1010. The tensile mechanical properties of the prepared blends were investigated, and the fracture surfaces of the blends were examined by means of the scanning electron microscope. The improved adhesion in a 15% HIPS/75% PA1010 blend with 10% HIPS-g-MA copolymer was detected. The morphology of fibrillar ligaments formed by PA1010 connecting HIPS particles was observed. (C) 1999 John Wiley & Sons, Inc.

Thermally stable interpenetrating polymer networks for second-order nonlinear optical materials

We report several kinds of interpenetrating polymer networks (IPNs) with nonlinear optical (NLO) properties. DMA spectra show that the two components of the IPNs have good compatibility with each other. The NLO materials have good optical transparency. The thermal stability of alignment was improved and the poled order remained very high. (C) 1999 John Wiley & Sons, Inc.

A study of the effect of shell content on the mechanical properties of polycarbonate/poly(butyl acrylate)-cs-poly(methyl methacrylate) blends

The toughening effect of the shell content of a core-shell latex polymer poly(butyl acrylate) (PBA)-cs-poly(methyl methacrylate) (PMMA) on its blends with polycarbonate (PC) was studied. The changes of mechanical properties, morphology, and compatibility of the blends of PC/PBA-cs-PMMA with the change of the shell thickness of PBA-cs-PMMA were investigated. It is interesting to notice that mechanical properties of the blends are very sensitive to the shell thickness (i.e., shell content), and that there is a possibility to adjust the impact and tensile properties of the blend by selecting a PBA-cs-PMMA with a proper core/shell ratio. Hence, a modified PC material with balanced mechanical properties may be prepared.

Thermodynamics of blends of poly(ethylene oxide) with poly(methyl methacrylate) and poly(vinyl acetate): prediction of miscibility based on Flory solution theory modified by Hamada

Flory solution theory modified by Hamada et al. (Macromolecules, 1980, 13, 729) was used to predict the miscibility of blends of poly(ethylene oxide) with poly(methyl methacrylate) (PEO-aPMMA) and with poly(vinyl acetate) (PEO-PVAc). Interaction parameters of a PEO-aPMMA blend with the weight ratio of PEO/aPMMA = 50/50 at the temperature range of 393-433 K and PEO-PVAc blends with different compositions and temperatures were calculated from the determined equation-of-state parameters based on Flory solution theory modified by Hamada ed al. Results show that interaction parameters of the PEO-aPMMA blend are negative and can be comparable with values obtained from neutron-scattering measurements by Ito et al. (Macromolecules, 1987, 20, 2213). Also, interaction parameters and excess volumes of PEO-PVAc blends are negative and increase with enhancing the content of PEO and the temperature. (C) 1998 Elsevier Science Ltd. All rights reserved.

Compatibilizing effects and mechanism of compatibilization of LLDPE/PEO blends by EAA

The compatibilizing effects of the compatibilizer, ethylene-acrylic acid random copolymer (EAA), on linear low density polyethylene (LLDPE)/poly(ethylene oxide) (PEO) blends and the mechanism of compatibilization of the blends have been studied. Morphology and microstructures as characterized by SEM, DMA, DSC and IR show that EAA can act as an effective compatibilizer, and the mechanism of compatibilization is due to the compatibility of amorphous phases between EAA and LLDPE, and intermolecular interaction between the carboxylic groups in EAA. and the ethereal oxygens in PEG.

Morphology and properties of [PPO-PDMS-PHS](n) segmented ternary copolymers

The morphology and properties of [ PPO-PDMS-PHS](n) segmented ternary copolymers were investigated by DMA, TEM and SAXS techniques. It is shown that the continuous phase of [PPO-PDMS-PHS](n) is the compatible phase composed of PDMS, PPO and PHS segments, and that there exist two dispersed phases, i, e. the PDMS phase and a mixed phase of half hard ( PHS) and hard ( PPO) segments. The tan delta vs. T curve of the segmented ternary copolymer with 66.7% (W/W) PDMS shows a rather high plateau in the temperature range from -120 degrees C to 200 degrees C, which indicates that the copolymer has the characteristics of microphase separation as well as compatibility of block copolymers, respectively. Meanwhile, it has good tensile properties, which means that [PPO-PDMS-PHS](n) has overcome the weakness of low strength of block or segmented copolymers containing PDMS.

Study of the blends containing core-shell latex polymer

Polycarbonate (PC) and a core-shell latex polymer composed of poly(butyl acrylate) and poly(methyl methacrylate) (PBA-cs-PMMA) as core and shell, respectively, were mixed using a Brabender-like apparatus under different conditions. The mechanical properties, the morphology and the processability of the blends were investigated. Because of the good compatibility of PC and PMMA, even dispersion of PBA-cs-PMMA in PC matrix and good adhesion between the components have been achieved. PBA-cs-PMMA is thus a very good impact modifier for PC. The toughening mechanism is both cavitation and shear yielding, as indicated by SEM observation. (C) 1997 Elsevier Science Ltd.

Morphology and mechanical properties of PP/HMWPE blends

Mechanical properties and morphology of blends of polypropylene (PP) with high molecular weight polyethylene (HMWPE) prepared by coprecipitation from xylene solution are investigated. Compared to blends of PP with commercial high-density polyethylene (HDPE), the mechanical properties of the blends of PP/HMWPE are much superior to those of PP/HDPE blends. Not only is the tensile strength stronger, but also the elongation at break is much higher than that of the PP/HDPE blends of the same composition. These differences increase with increasing HMWPE and HDPE content. Scanning electron microscopy of the fracture surface resulting from the tensile tests shows that the compatibility in PP/HMWPE blends is much better than that in PP/HDPE blends. This is most likely attributable to the enhanced chain entanglement of HMWPE with the PP in the amorphous phase due to the lower crystallinity, owing to the high molecular weight of the HMWPE, and a much more flexible chain. The thermal behavior and spherulite morphology of both blends are also investigated.

The miscibility of homopolymer random copolymer blends .1. Poly(styrene-co-acrylonitrile) poly(ethyl methacrylate) and poly(styrene-co-acrylonitrile) poly(methyl methacrylate) blends

The miscibility of blends of poly(styrene-co-acrylonitrile) (SAN) with poly(methyl methacrylate) (PMMA) or poly(ethyl methacrylate) (PEMA) has been investigated by means of NMR and DSC techniques. It is found that there are intermolecular interactions between the phenyl groups in SAN and carbonyl groups in PMMA or PEMA, and the strength of this intermolecular interaction strongly depends on the properties of ester side groups in PEMA or PMMA, composition of the blends and a certain composition of the copolymer. It is this specific interaction instead of the intramolecular repulsion force within the copolymer that plays a key role for the miscibility of SAN/PMMA and SAN/PEMA blends.

The miscibility of homopolymer random copolymer blends .4. Poly(vinylidene chloride-co-acrylonitrile) poly(methyl methacrylate) blends

The miscibility of blends of poly(vinylidene chloride-co-acrylonitrile) (VDC-AN) and poly(methyl methacrylate) (PMMA) has been studied with DSC, FT-IR, and NMR methods. The results indicate that the VDC-AN/PMMA blends are miscibile on a molecular level, and the dipole-dipole interactions between C=O and C-Cl-2 and/or interpolymer hydrogen bondings between COOCH3 and CN and CCl groups play the role on the miscibility of the blends. It is found that the -CCl2- groups have two different chemical environments in the pure VDC-AN copolymer, which may result from the different configurations of the copolymer, such as -CCl2- groups in the ''alternating'' segments and -CCl2- groups in the ''blocky'' segments as proposed. It is the -CCl2- group in the ''alternating'' segment that takes part in the dipole-dipole interaction with C=O group in PMMA.

Studies on water-swellable elastomer .1. Synthesis and characterization of amphiphilic polymer

A new amphiphilic polymer i.e., polyethylene glycol (PEG) grafted crystalline neoprene, which was used as compatibilizer to improve the compatibility of elastomer and water-absorbent resin, has been investigated. The synthesis was based on the reaction between chlorine in neoprene and sodium salts of PEG. PEGs with molecular weights of 600 and 2000 were used. The grafting percent and the PEG content were calculated through elemental analysis of chlorine in the resulted copolymers. The maximum grafting percent of copolymers was ca. 24.80%. The molecular parameters such as number-average molecular weight and the average number of grafting chains on one CR backbone were also calculated and discussed. (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.

Miscibility and crystallization behavior of thermosetting polyimide thermoplastic polyimide blends

Compatibility, morphology, crystalline structure and mechanical properties of the blends of a thermosetting polyimide with thermoplastic polyimides consisting of dianhydrides of different lengths have been studied by the use of dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS) techniques. The results of our research show that the blends change from compatible to semi-compatible when the difference between the length of the dianhydrides of the two components increases. Addition of a thermoplastic polyimide inhibits the crystallization of the thermosetting component. However, this effect decreases with increasing length of the dianhydrides and the distribution of the molecules of the thermoplastic polyimide component changes from interlamellar to interfibrillar. Impact strength and morphology of the fractured surfaces indicate that among the semiinterpenetrating polymer networks (semi-IPN) obtained the toughening effect of the partially compatible one is the best. The results are discussed in terms of charge transfer interaction between imide group and p-phenylene group.

MISCIBILITY STUDIES OF POLY(ETHYLENE OXIDE)-POLY(VINYL ACETATE) BLENDS BY VISCOMETRY METHODS

The intrinsic viscosities of poly(ethylene oxide)-poly(vinyl acetate) blends (PEO-PVA) have been measured in chloroform as a function of molecular weights of blend components and compositions. The interaction parameters Delta b obtained from the modified Krigbaum and Wall theory and the differences between the intrinsic viscosities of polymer mixtures and the weight-average intrinsic viscosities of the two blend components were both used to characterize the extent of miscibility of the blend mixtures. (C) 1995 John Wiley and Sons, Inc.