摘要:

AbstractBlends of a poly[2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole] (FBI) polymer with polyarylate (PA) yield films exhibiting synergistic mechanical properties. The break strength of the blended materials exceeded the strength of the stronger polymer in its 100% form. The molecular interaction and compatibility of PBI/PA have been investigated and confirmed by infrared, dynamic mechanical analysis and thermogravimetric analysis. For example, interactions were typically found between the carbonyls and the imidazole in these systems, and there was a shift of the carbonyl band to lower frequency. DMA study of a (40/60) PBI/PA film blend revealed the existence of twoTgvalues (e.g., 245 and 362°C). The shift of theTgfrom each individual component strongly suggested that FBI and PA interact on a molecular scale. Membranes made from a solution of a 60/40 (weight %) mixture of PBI and polyarylate exhibited excellent UF properties: a flux of 60–80 gfd at 50 psi and a rejection of 90–99% of cytochrome‐c (MW = 12,000). The HPLC results confirmed the red color species (Vitamin 12 and cytochrome‐c) were quantitatively removed. Further experiments indicated that the excellent UF properties were due to the novel combination of PBI and PA which offered a unique absorption and ionic‐ex

ISSN:0032-3888    

DOI:10.1111/j.0307-6962.2005.00454.x

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractExtrusion measurements have been carried out on blends of nylon 6 and a liquid‐crystalline copolyesteramide (LCP). The flow curves at low temperature show a behavior similar to that of pure LCP with a rapid rise of the viscosity at low shear rates. At high shear rates the viscosity is lower than that for each of the two components. This minimum has been attributed to the lack of interactions between the two phases and to the formation of fibrils of the LCP phase. The SEM analysis shows, indeed, that fibrils of the LCP phase are produced in the convergent flow at the inlet of the capillary at high shear rates. These fibrils are lost during the flow in the long capillar

ISSN:0032-3888    

DOI:10.1002/pen.760300103

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractA thermotropic liquid crystalline polyester (LCP) with a long flexible spacer group in the main chain was prepared by melt polymerization and mixed with poly(ethylene terephthalate) (PET). Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) studies revealed that the crystallization of PET was accelerated by the addition of LCP in the matrix. Interfacial adhesion between PET and LCP was much improved by introduction of a long flexible spacer in the main chain. Fibers of the blend with 30 wt percent of LCP had fine microfibrillar structure with a large aspect ratio formed in the matrix. Initial modulus and ultimate strength were highly elevated by the addition of LCP due to good interfacial adhesion and microfibrillar structure of LCP in the blend.

ISSN:0032-3888    

DOI:10.1002/pen.760300104

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractPolymer blends of nylon 66 and thermotropic polyester with long flexible spacers in the main chains were prepared by melt mixing. The samples were made as single filaments by passing the polymer blend through a small and round die of a capillary rheometer. Mechanical properties of blends showed that the modulus and strength of nylon 66 could be improved without reduction of extensibility. The morphology of fractured surfaces was observed by a scanning electron microscope (SEM). It showed that the microfibrillar structure of a thermotropic polyester was formed by extensional flow while the spherical and ellipsoidal particles in the nylon 66 (matrix polymer) were produced by shear flow. The polyester particles were occasionally covered with adhering matrix polymer because of good adhesion between these two polymers. They were highly elongated by tensile stress without loss of elongational characteristics of blends. This fact was explained by very good adhesion between the two phases.

ISSN:0032-3888    

DOI:10.1002/pen.760300105

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractNew block copolymers of polystyrene with polyesters have been synthesized and investigated as compatibilizing agents. The addition of block copolymers in immiscible blends of polybutylene terephthalate and (i) polystyrene, (ii) polystyrene/poly(2,6‐dimethyl 1,4‐phenylene oxide) as well as (iii) high impact polystyrene drastically reduced the dimensions of the dispersed phase and stabilized the phase growth with annealing time. Stress‐strain curves for the binary blends indicate brittle behavior. The addition of more than 10 wt% of block copolymers transforms their brittle characteristics to ductile beh

ISSN:0032-3888    

DOI:10.1002/pen.760300106

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractThe properties of miscible phenolphthalein poly(ether ether ketone) (PEK‐C)/polysulfone blends have been measured by dynamic mechanical analysis and tensile testing. The blends are found to have single glass transitions that vary continuously with the composition. The tensile moduli exhibit positive deviations from simple additivity as expected for miscible blends. Remarkably, positive deviations were also observed for tensile strength. Embrittlement, or transition from the brittle to ductile mode of failure, occurs at 50‐30 wt % PEK‐C. These observations suggest that mixing on the segmental level has occurred and that there is enough interaction between the components to retard internal mobility signific

ISSN:0032-3888    

DOI:10.1002/pen.760300107

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractTensile, cyclic, and tear properties were compared for several styrene‐butadiene‐styrene (SBS) triblock copolymers, KRATON D2104, D1101 and D1102, and blends of D2104 with monodisperse polystyrene of various molecular weights. D2104 is expected to have a morphology of polystyrene spheres in a polybutadiene continuous matrix. The mechanical properties of D2104 were compared to the properties of SBS materials which have higher styrene contents and exhibit cylindrical or lamellar morphologies. Blending the D2104 with polystyrene (molecular weights ranging from 2000 to 51,000) to 24 and 28 wt % total styrene content showed that the tensile strength obtained for a blend was dependent on the molecular weight of the polystyrene added. Cycle testing of the D2104‐polystyrene blends showed that with increasing polystyrene content the softening effect increases with increasing strain. This indicates that the degree of phase continuity of the polystyrene domains may be changing from a spherical morphology to a cylindrical morphology similar to that of pure SBS with 28 wt % styrene content. Tear test results for the blends were also observed to be similar to the results for pure SBS of the same total polystyrene co

ISSN:0032-3888    

DOI:10.1002/pen.760300108

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractA major obstacle to the study of polymer blends has been the lack of a convenient technique for measurement of molecular weight. Melt rheometry, while giving useful information related to processing and end‐use performance, is incapable of providing detailed information on the individual components. This work describes the use of size exclusion chromatography (SEC) to study the molecular‐weight distributions of polycarbonates and aromatic polyesters in blends of the two. SEC of the polycarbonate is achieved in a solvent which dissolves the polycarbonate, but not the polyester, while SEC is performed in a solvent which dissolves both components, but using selective detection. Thus, SEC is used to examine the individual components of the blend, while rheometry can be used to study the blend as a whole. This combination of techniques has been successfully used to analyze the effect of moisture, processing conditions, and recycling on blend propert

ISSN:0032-3888    

DOI:10.1002/pen.760300109

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760300101

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY