Impact behavior of phenolphthalein poly(ether sulfone) ultrahigh molecular weight polyethylene blends

This work presents the structure and impact properties of phenolphthalein poly(ether sulfone) blended with ultrahigh molecular weight polyethylene (PES-C/UHMWPE) at different compositions. The addition of UHMWPE can considerably improve the Charpy and Izod impact strength of the blends. The fracture surface is examined to demonstrate the toughening mechanics related to the modified PES-C resin. (C) 1998 John Wiley & Sons, Inc.

Morphological studies of polyamide 1010/polypropylene blends

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the morphology of blends of PA1010 and polypropylene (PP) compatibilized with polypropylene grafted with glycidyl methacrylate (PP-g-GMA). It is found that the morphologies are dependent on the content of glycidyl methacrylate in PP-g-GMA and the mixing time. The size of the dispersed PP particles decreases as the content of GMA in the PP-g-GMA increases for binary blends of PA1010 and PP-g-GMA. Similar results are obtained for changing the mixing time. Ternary blends of PA1010, PP, and PP-g-GMA indicate that morphologies depend on the content of glycidyl metyacrylate in the PP-g-GMA and the miscibility of PP and PP-g-GMA. By changing the content of GMA in PP-g-GMA, it was possible to introduce significant changes of morphology. A matrix removal TEM method is used to investigate the interfacial structure of PA1010/PP blends containing PP-g-GMA as a compatibilizer. This technique shows the reaction product between PA1010 and PP-g-GMA to be located at interface as a surrounding layer around domain particles. SEM observation on the interface shows that the adhesion between PA1010 and pure PP is very weak and their interface boundary is sharp. For the samples of PA1010 and PP-g-GMA, it was found that the interface was not so obvious, and the reaction between PA1010 and PP-g-GMA strengthens the interface significantly. (C) 1997 Elsevier Science Ltd.

Mechanical and structural characteristics of phenolphthalein poly(ether sulfone) ultra-high molecular weight polyethylene blends

Mechanical and structural properties of blends of phenolphthalein poly(ether sulfone) (PBS-C) with ultra-high molecular weight polyethylene (UHMWPE) were investigated using tensile and bending testing, scanning electron microscopy and transition electron microscopy. The incorporation of minor amounts of UHMWPE (2 wt.-%) into PES-C has a reinforcement effect. With higher concentrations of UHMWPE, the mechanical properties decrease gradually. Structural studies demonstrated that the blends are multiphasic in the whole composition range. The minor UHMWPE, dispersed uniformly and oriented along the flow direction, as well as the strong interfacial adhesion contribute to the increase of the mechanical performance of the blends. The domain size of the UHMWPE phase was found to increase with the increase of its concentration.

Crystallization kinetics and morphology of poly(beta-hydroxybutyrate) and poly(vinyl acetate) blends

The crystallization behavior and morphology of poly(beta-hydroxybutyrate) and poly(vinyl acetate) blends have been studied with DSC, POM, SAXS and WAXD methods. The results indicate that the overall crystallization rate and spherulite growth rate are slower in the blends than that in the pure PHB. The addition of PVAc has no effect on the crystal structure of PHB, but affects its crystalline morphology. During crystallization of PHB, PVAc chains were being rejected into the region between the lamellae of crystalline PHB. (C) 1997 Elsevier Science Ltd.

Effects of molecular weight and interaction parameter on the glass transition temperature of polystyrene mixtures and its blends with polystyrene/poly(2,6-dimethyl-p-phenylene oxide)

The glass transition temperature (T-g) of mixtures of polystyrene (PS) with different molecular weight and of blends of poly(2,6-dimethyl-p-phenylene oxide) (PPO) and polystyrene with different molecular weight (DMWPS) was studied by a DSC method. For the whole range of composition, the curves of T-g vs composition obtained by experiment were compared with predictions from the Fox, Gordon-Taylor, Couchman and Lu-Weiss, equations. It was found that the experimental results were not in agreement with those from the Fox, Gordon-TayIor and Couchman equations for the binary mixtures of DMWPS, where the interaction parameter chi was approximately zero. However, for the blends PPO/DMWPS (chi < 0), with an increase of molecular weight of PS, it was shown that the experimental results fitted well with those obtained from the Couchman, Gordon-Taylor and Fox equations, respectively. Furthermore, the Gordon-Taylor equation was nearly identical to the Lu-Weiss equation when \chi\ was not very large. Further, the dependence of the change of heat capacity associated with the glass transition (Delta C-p) on the molecular weight of PS was investigated and an empirical equation was presented. (C) 1997 Elsevier Science Ltd.

Morphology, mechanical properties and interfacial behaviour of PA1010/PP/PP-g-GMA ternary blends

Morphology, mechanical properties, and interfacial interaction of polyamide 1010/polypropylene (PA1010/ PP) blends compatibilized with polypropylene grafted with glycidyl methacrylate (PP-g-GMA) were studied. It was found that the size of the PP domains, tensile and impact strength of ternary blends, and adhesion fracture energy between two layers of PA1010 and PP were all significantly dependent on the PP-g-GMA contents in the PP layer. Correlations between morphology and related properties were sought. The improvements in properties have been attributed to chemical and physical interaction occurring between PA1010 and PP-g-GMA. (C) 1997 Elsevier Science Ltd.

Poly(vinyl methyl ether) poly(methyl methacrylate) blends using diblock copolymer of styrene and methyl methacrylate as compatibilizer

Blends of poly(vinyl methyl ether) (PVME) and poly(methyl methacrylate) (PMMA) compatibilized by poly(styrene-block-methyl methacrylate) (P(S-b-MMA)) ale studied by FT-IR, DSC, excimer fluorescence spectrometry, and scanning electron microscopy (SEM). In FT-IR measurement the ratio of absorption intensity at 1107 cm(-1) to that at 1085 cm(-1) (I-1107/I-1085) reaches a minimum at about 10wt% block copolymer content. DSC results show that the glass transition temperature of PVME in the blends has a maximum at 10 wt% copolymer content. In plots of the ratio of excimer-to-monomer fluorescence emission intensities (I-E/I-M) VS block copolymer content, I-E/I-M increases rapidly above 10%. Ail these phenomena show that PS block chains penetrate into PVME: domains on addition of block copolymer. Above 10% copolymer content, block copolymer chains tend to form micelles in bulk phase.

Studies on poly(ether ether ketone ketone) poly(ether biphenyl ether ketone ketone) copolymers and blends

We synthesized a series of polymers: poly(ether ether ketone ketone)(PEEKK), poly(ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation, We also prepared a series of PEEKK-PEBEKK blends, By using DSC method, we found that T-g of the copolymers and the blends rose with the increasing of biphenyl contents in the polymers, T-c of the copolymers and the blends is higher than the corresponding homopolymer. From the results, we think that PEEKK-PEBEKK copolymer and blends are miscible and the copolymer is random.

Liquid crystalline polymer as a processing agent in blends of poly(ether-ketone)/LCP70

Blends of a liquid crystalline thermotropic copolyester (LCP70) and an amorphous phenolphthalein based poly(ether-ketone)(PEK-C) with two viscosities were prepared by melt blending. The blends' morphology, rheological and mechanical properties were investigated by DSC, SEM, mechanical and rheological tests. It was observed that the optimum composition of the PEK-C/LCP70 blend was 10 wt% LCP for both mechanical and rheological properties. When the LCP content was less than 10%, the LCP phase existed as finely dispersed fibrous domains with a diameter of about 1 mu m in the matrix, and both tensile and flexural properties were improved. In contrast, when the LCP content reached 20% or more, the LCP domains coalesced to ellipsoidal particles with a diameter of about 5 mu m, and the mechanical properties decreased as a result. It is demonstrated that pure PEK-C with a high viscosity which was difficult to process by melt extrusion, could be extruded conveniently when 10% LCP70 was incorporated. It is emphasized that LCP not only can be used as a reinforcing phase but also an effective processing agent for engineering thermoplastics, especially for those with high viscosity and narrow processing window. (C) 1997 Elsevier Science Ltd.

The miscibility of homopolymer random copolymer blends .3. Blends of SAA with polymethacrylates and polyesters

The miscibility of blends of poly(styrene-co-allyl alcohol) (SAA) with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(n-butyl methacrylate) (PnBMA), poly-epsilon-caprolactone (PCL) or polycarbonate (PC) has been studied by means of NMR, FT-IR and DSC techniques. It was found that SAA and PMMA, PEMA or PCL form miscible blends and SAA is only partially miscible with PC or PnBMA. Both phenyl groups and hydroxyl groups in SAA are involved in the intermolecular interactions between SAA and PMMA, PEMA or PCL. Also the hydroxyl-carbonyl hydrogen bonds existing in all the miscible blends studied are formed partially at the expense of the disruption of self-association of hydroxyl groups in pure SAA. (C) 1997 Elsevier Science Ltd. All rights reserved.

Crystallization behavior of poly(propylene)/polyamide 1010 blends using poly(propylene)-graft glycidyl methacrylate as compatibilizer

Polyamide 1010/poly(propylene) (PA1010/PP) blends were investigated with and without the addition of poly(propylene)-graft-glycidyl methacrylate (PP-g-GMA). The effect of the compatibilizer on the thermal properties and crystallization behavior was determined by differential scanning calorimetry and wide-angle X-ray diffraction. From the results it is found that the crystallization of PA 1010 is significantly affected by the presence of PP-g-GMA. PP/PA 1010 (75/25) blends containing higher amounts of PP-g-GMA show concurrent crystallization at the crystallization temperature of PP. Isothermal crystallization kinetics also were performed in order to investigate the influence of the compatibilized process on the nucleation and growth mechanism. In the PP/PA 1010 (25/75) blends, concurrent crystallization behavior was not observed, even though the amount of PPg-GMA was high.

Crystallization behavior of blends of high-density polyethylene with novel linear low-density polyethylene

Blends of high-density polyethylene (HDPE) with novel linear low-density polyethylene (LLDPE) samples in the whole range of compositions were investigated by means of differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD). The LLDPEs are ethylene/octene-1 copolymers prepared with a single-site catalyst, with a narrower distribution of branches compared to Ziegler-Natta type polymers. It was found that cocrystallization or separate crystallization in the blends profoundly depends on the content of branches in the LLDPE, while the critical branch content of the novel LLDPE for separate crystallization is much lower than that of commercial LLDPE (prepared with Ziegler-Natta catalysts). This implies that the miscibility of linear and branched polyethylene is also affected by the distribution of branches. The marked expansion of the unit cell in cocrystals, which are formed by HDPE with the novel LLDPE, indicates that the branches are included in the crystal lattice during the cocrystallization process. The result is very helpful to understand the phenomenon that the unit cell dimensions of commercial branched polyethylene are larger than those of linear polyethylene.

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.

Miscibility and crystallization of poly(beta-hydroxybutyrate) and poly(p-vinylphenol) blends

The miscibility and crystallization behavior of poly(beta-hydroxybutyrate) (PHB) and poly(p-vinylphenol) (PVPh) blends were studied by differential scanning calorimetry and optical microscopy (OM). The blends exhibit a single composition-dependent glass transition temperature, characteristic of miscible systems, A depression of the equilibrium melting temperature of PHB is observed. The interaction parameter values obtained from analysis of the melting point depression are of large negative values, which suggests that PHB and PVPh blends are thermodynamically miscible in the melt. Isothermal crystallization kinetics in the miscible blend system PHB/PVPh was examined by OM. The presence of the amorphous PVPh component results in a reduction in the rate of spherulite growth of PHB. The spherulite growth rate is analyzed using the Lauritzen-Hoffman model, The isothermally crystallized blends of PHB/PVPh were examined by wide-angle X-ray diffraction and smell-angle X-ray scattering (SAXS). The long period obtained from SAXS increases with the increase in PVPh component, which implies that the amorphous PVPh is squeezed into the interlamallar region of PHB.

Morphology, thermal behavior, and mechanical properties of PA1010/PP and PA1010/PP-g-GMA blends

The modification of polypropylene (PP) was accomplished by melt grafting glycidyl methacrylate (GMA) on its molecular chains. The resulting PP-g-GMA was used to prepare binary blends of polyamide 1010 (PA1010) and PP-g-GMA. Different blend morphologies were observed by scanning electron microscopy (SEM) according to the nature and content of PA1010 used. Comparing the PA1010/PP-g-GMA and PA1010/PP binary blends, the size of the domains of PP-g-GMA were much smaller than that of PP at the same compositions. It was found that mechanical properties of PA1010/PP-g-GMA blends were obviously better than that of PA1010/PP blends, and the mechanical properties were significantly influenced by wetting conditions for uncompatibilized and compatibilized blends. A different dependence of the flexural modulus on water was found for PA1010/PP and PA1010/PP-g-GMA. These behaviors could be attributed to the chemical interactions between the two components and good dispersion in PA1010/PP-g-GMA blends. Thermal and rheological analyses were performed to confirm the possible chemical reactions taking place during the blending process. (C) 1997 John Wiley & Sons, Inc.