ISSN:0032-3888    

DOI:10.1002/pen.760241702

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractWe discuss the free‐energy expressions for homogeneous melts and their blends, based on our hole theory. Equation of state (PVT) and free energy of mixing (ΔGm) are considered from a common point of view without the introduction of additional parameters to pass from the first to the second set of properties. Practical problems arise from the fact that ΔGmrepresents a difference between large quantities. As illustrations we analyze two typical systems. One is the n − C6+ n − C16pair where PVT and ΔGm, the latter at atmospheric pressure only, have been studied experimentally. The other is n ‐ C6with a low and high molecular weight respectively of polyethylene as solute. Here the PVT relations of the components only are known. The effects of intercomponent attractions, temperature, pressure, and molecular weight on phase behavior are investigated. Critical coordinates, lower critical‐solution temperatures (LCST) and their pressure dependence are computed. An iso‐free volume condition obtains for this dependence where free volume is defined by the hole fraction inherent in the theory. Comparisons with experimental observations and other theoretical computations for different molecular weights are limited by the effect of polydispersity. Moreover, cloud point curves are shown. We finally compute the composition and pressure dependence of the χ‐parameter which is implicit in the theory. We conclude with some comments regardi

ISSN:0032-3888    

DOI:10.1002/pen.760241703

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760241704

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe miscibility of polymer blends is related to the polymer‐polymer interaction parameter χ23, Several methods can be used to evaluate this parameter and five of the most important ones are reviewed: two equilibrium methods (melting‐point depression and vapor sorption), a transport method (inverse‐phase gas chromatography) and two scattering methods (neutron scattering and small‐angle x‐ray scattering). Examples are cited where χ23values for a given blend were determined by several of these methods. This comparison leads to the conclusion that a reasonable agreement is often reached despite conceptual differences between the metho

ISSN:0032-3888    

DOI:10.1002/pen.760241705

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractIn a series of publications we reported on melt rheology, morphology, and mechanical properties of the poly(ethylene terephthalate)/poly(amide‐6,6) blends (PET/PA). The non‐oriented samples had poor interphase bonding resulting in low impact and tensile strengths. To improve these properties the ester‐amide interchange reaction was carried out in solution and in melt. In the latter case a Brabender Plastograph was used in the mixing chamber or twin‐screw extruder configurations with p‐toluenesulfonic acid as a catalyst. The interchange reaction was followed by 400 MHz proton and13C nuclear magnetic resonance spe

ISSN:0032-3888    

DOI:10.1002/pen.760241706

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractIt is shown that ion‐dipole interactions induce considerable miscibility enhancement in blends of styrene ionomers with poly(alkylene oxides). Dynamic mechanical studies, in conjunction with transparency and brittleness of the samples, are used to evaluate miscibility. The effect is clearly thermodynamics in that phase separation can be induced in miscible samples by raising the temperature, with miscibility reestablished ons cooling. The miscibility enhancement in these systems is compared with that resulting from hydrogen bonding. In addition to the styrene/alkylene oxide system, ion‐dipole interactions are found to be effective in enhancing the miscibility of many ionic polymer/polar polymer pairs. The ionomers used in this study were styrene lithium methacrylate and ethyl acrylate lithium acrylate copolymers, while polyethers, polysulfides, polyesters, polyimines, and substituted polyethylenses served as polar polym

ISSN:0032-3888    

DOI:10.1002/pen.760241707

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractBlends of polycarbonate/polystyrene (PC/PS), polycarbonate/polypropylene (PC/PP) and ternary blends of the three components (PC/PS/PP) were studied. Extrudate swell of the molten blends increased with increasing concentrations of the minor components and leveled off at characteristic blend compositions. These compositions corresponded to the limits of compatibility as judged by the onset of brittleness in tensile tests. Both PS and PP appear to have some limited practical compatibility with PC. The change in extrudate swell behavior with concentration may be a rapid and convenient test for the effective concentration limits of partially miscible polymers.

ISSN:0032-3888    

DOI:10.1002/pen.760241708

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of addition of an ethylene‐propylene block polymer on rheological and mechanical properties of a linear‐low‐density polyethylene/polypropylene blend was examined. The samples were prepared by melt blending in a twin‐screw extruder followed by injection molding. The single‐, two‐ and three‐component systems were treated the same way. The mechanical behavior of the blends was evaluated by means of tensile, and flexural, tests at 23 and −40°C. The capillary, elongational, and dynamic‐flow measurements were

ISSN:0032-3888    

DOI:10.1002/pen.760241709

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractAn experimental study of the development of phase morphology in incompatible polymer melt blends of polyethylene/polystyrene (PE/PS), polyethylene/polycarbonate (PE/PC), and polyethylene/nylon‐6 (PE/N6) is presented. Different temperatures (180°C, 240°C) of mixing and polyethylene molecular‐ weight levels were used in the PE/PS studies. Little variation in the cross‐sectional phase morphology of the PE/PS extrudates was observed with these variables, though the morphology became finer with increased shear rate/stress in capillary die flow. Variations in the longitudinal morphology are observed with continuous filaments of dispersed phase only arising when the dispersed phase has an equal or lower viscosity than the continuous phase. The PE/N6 and PE/PC, especially the former, give coarser morphologies when the N6 and PC are the continuous phases. This was attributed to larger inter‐facial tensions. The effect of viscoelasticity was also

ISSN:0032-3888    

DOI:10.1002/pen.760241710

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY

摘要:

AbstractOxygen and water vapor permeability studies were carried out on binary polyethylene/polyamide immiscible blends incorporating three polyethylene resins (LDPE, LLDPE, and HDsPE), and three polyamide resins (PA‐6, PA‐6,6, and modified PA‐6,6m). It was found that the incorporation of PA into PE reduces the oxygen permeability while water vapor permeability is increased. In the range of 0 to 30 weight percent of PA, the oxygen permeability of PE was reduced by a factor of 2.8 to 3.6. Maximum water vapor permeabilities increased: for HDPE by a factor of about 2.6 to 3.1 and for LDPE and LLDPE blends by abou

ISSN:0032-3888    

DOI:10.1002/pen.760241711

出版商:Society of Plastics Engineers, Inc.    

年代:1984

数据来源: WILEY