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  • 1980-1984  (3,021)
  • 1965-1969  (1,448)
  • Chemical Engineering  (4,044)
  • pharmacokinetics  (424)
  • Nuclear reactions
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  • 101
    Electronic Resource
    Electronic Resource
    Experimental study and computer simulation of a two-stage continuous polymerization process for the production of methyl methacrylate (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 442-454 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The two major problems encountered in industrial liquid-phase addition polymerization are: the heat released by highly exothermic reactions and the great increase in viscosity with conversion. The high rate or heat generation, coupled with the low thermal diffusivity of the reacting system, often lead to thermal runaway. Even with the process kept under marginal control, large temperature variations broaden the product molecular-weight distribution. Temperature control is particularly difficult in the Trommsdorff region, where reaction rate rapidly increases as temperature rises and viscosity builds up. A two-stage process is developed in this work to attack these problems and to achieve continuous operation of poly(methyl methacrylate) bulk polymerization. This process utilizes a continuous stirred-tank reactor (CSTR) as a first-stage prepolymerizer and a spray tower as the second-stage finishing reactor. Use of a CSTR offers good temperature control and product uniformity during the early stages of reaction and eases delivery of the reacting system to the second stage at the desired conversion and molecular-weight level. Spraying the partially polymerized mixture into the tower as fine droplets prior to the onset of gel effect eliminates the problems of transporting, agitating, and mixing a reacting system with a rapidly increasing viscosity. Heat of reaction is efficiently removed by a countercurrent stream of nitrogen in the tower, in direct contact with the falling droplets. The high surface-to-volume ratio of these small droplets facilitates heat transfer, and the problem of heat buildup can be efficiently controlled. Products from the bottom of the tower can then be melt-processed by conventional methods, such as extrusion. Experiments performed in the laboratory have demonstrated the feasibility of this proposed concept. Process optimization was in no way achieved due to serious space and equipment limitations. The process was thus further examined by computer simulation and model parameter sensitivity study. A practical design was recommended based on the model predictions.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240609
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  • 102
    Electronic Resource
    Electronic Resource
    An experimental study on the injection molding of thermosetting polyester resin (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 473-481 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An experimental study was conducted on the injection molding of a thermosetting polyester resin. For the study, a general-purpose unsaturated polyester resin was used, with benzoyl peroxide as initiator. A differential scanning calorimeter (DSC) was used for studying the curing kinetics, under isothermal curing conditions. A plunger-type injection-molding apparatus was constructed, and a rectangular mold cavity with glass windows on both sides was constructed, which permitted us to record on a film the changes in stress birefringence patterns in the mold cavity during the molding operation (i.e., during the isothermal cure, post cure, and subsequent cooling), using a crossed circular polariscope. The injection-molded specimens were used to determine the distribution of the degree of cure at various positions in the flow direction, and to relate the degree of cure to the dynamic mechanical properties.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240705
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  • 103
    Electronic Resource
    Electronic Resource
    Thermal catalytic polymerization of mortars impregnated with styrene-acrylonitrile (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1240-1244 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Standard test specimens of mortar were cured under water for 15 days to achieve satisfactory strength. They were dried without allowing dehydration reactions to occur, evacuated to 40 millimeters (mm) Hg, and impregnated with a styreneacrylonitrile comonomer, which gives the highest strength after polymerization. Positive pressure of 0.6 N/mm2 was applied and thermal catalytic polymerization was carried out. Optimum initiator concentration was found to be 2 percent. Strength (compressive and tensile) increases with polymerization temperature up to 120°C, above which rapid deterioration occurs due to monomer loss, production of short chains with high polymerization rates, and the possibility of polymer degradation at high temperature. Optimum polymerization period of' 10 hours was selected. Inexpensive methods for field polymerization were tried at 95°C. Hot water yields a strength more than double that obtained with a, flow of hot air and about 80 percent of that obtained radiolytically. While hot air accelerates evaporation, hot water forms a hydraulic head above the capillaries and decreases the monomer losses tremendously.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241605
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  • 104
    Electronic Resource
    Electronic Resource
    The influence of high storage humidity on some properties of solid propellantsThis paper is based on part of the work undertaken for a thesis for an M.Sc. degree in chemical Engineering by the first author under the supervision of the second author. (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 275-277 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The absorption of water vapor by propellants based on hydroxy-terminated polybutadiene and an isocyanate from atmospheres of increasing relative humidities, and the swelling index of the propellant which had absorbed various proportions of water, were measured in an attempt to establish the extent of hydrolytic damage. The method was found incapable of assessing such damage, but it was shown that there was no measurable absorption of vapor below 92 percent relative humidity (RH). The MEK/polymer and toluene/polymer interaction parameters were determined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240408
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  • 105
    Electronic Resource
    Electronic Resource
    Common structure, compatibility and complementarity of mathematical models of injection molding (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 673-685 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The hierarchy of mathematical models of injection molding is reviewed. Compatibility of the models of the hierarchy, usefulness of simultaneous applications of models formulated on several different levels of the hierarchy and compatability between physical approximations leading to the formulation of a model, and mathematical approximations used to solve numerically the governing equations of the model are discussed. This review is intended to facilitate the search for a model that is best suited to a given need and to indicate future research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240909
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  • 106
    Electronic Resource
    Electronic Resource
    General discussion on the role of computer aided engineering (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 716-721 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240914
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  • 107
    Electronic Resource
    Electronic Resource
    A metallurgical approach to the pre-yield and yield behavior of glassy polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 737-749 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper discusses some new mechanical and small angle neutron scattering (SANS) data on glassy polymers, both thermoplastics and thermoset resins, from the point of view of dislocation-like defects introduced in the molecular chain arrangement by deformation. In the pre-yield stage, a new parameter, the work-hardening rate K is introduced and its measurement is defined. Experiments are reported which show that K can be used as a very sensitive probe for microstructural changes during physical aging or curing. In one hand, the theory of yielding is revisited to make clear how dislocations and their propagation in polymers depend on specific features like entanglements and chain stiffness. On this basis, experimental internal stresses and activation volumes at yield (i.e., the temperature slope of yield stress) are accounted for. On the other hand, SANS data provide us with experimental evidence at the scale of 10 to 20 Å of the dislocation nature of the molecular “shear defects” introduced in the polymer by deformation. Finally, temperature is known to have a pronounced influence on yield processes. It is shown that two distinct deformation modes exist below and above a critical temperature Tc. Above Tc, a dislocation climb, which probably involves β-processes, gives rise to a “diffusional” deformation mode where chains within a (diffuse) shear band are no longer oriented. A tentative formalization of this behavior, and its relation to the small strain creep of polymers, are then presented.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241004
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  • 108
    Electronic Resource
    Electronic Resource
    The role of molecular networks and thermally activated processes in the deformation behavior of polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 724-736 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The deformation behavior of three polymers, polyethylene terephthalate (PET), polymethylmethacrylate (PMMA), and linear polyethylene (LPE) is considered in terms of two key factors, the stretching of a molecular network and the influence of thermally activated processes. In PET the observation of a natural draw ratio leads to studies of shrinkage, shrinkage force, and optical birefringence to define the nature of the network. The network is further exemplified by measurements of the molecular reorientation in deformation bands, spectroscopic studies of molecular orientation in drawing, and the concept of a true stress-strain curve. Yield and plastic deformation are also to be considered as thermally activated processes, but it appears that a major part of the flow stress is associated with the stretching of the molecular network. In PMMA the concept of a true stress strain curve also appears to be valuable, but the possibility of network breakdown during deformation has to be admitted as an extra complexity. In LPE the concept of a molecular network embracing both crystalline and non-crystalline material is helpful in understanding the drawing behavior. There is also direct evidence for the existence of a network from measurements of shrinkage and shrinkage force, and the existence of a true-stress strain curve. However, the dominant contribution to the flow stress now appears to come from thermally activated processes, with a key contribution from a small activation volume process which is tentatively associated with slip in the crystalline regions.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241003
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  • 109
    Electronic Resource
    Electronic Resource
    Analysis of deformation processes in glassy polycarbonate using internal friction measurements during a tensile test (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 886-894 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Internal friction has been measured by torsion at 1 Hz during tensile tests performed on glassy polycarbonate at room-temperature. Steady-state flow and transient effects have been studied during continuous tensile tests and strain-rate changes. During steady-state, internal friction and flow-stress vary in a similar way with strain-rate. But during transients, internal friction varies continuously while flow-stress passes through a maximum (or a minimum). These results are interpreted assuming that non-elastic deformation of glassy polymers requires some microscopic discontinuous processes such as motion of defects. Two parameters are considered: the velocity v and the density ρ of mobile defects. Assuming that the former is directly related to the flow stress, it has been shown that internal friction is related to the density of mobile defects ρ. This feature is used to interpret the different stages of a tensile test curve. Activation volumes for both velocity and density of mobile defects are calculated from experimental data.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241108
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  • 110
    Electronic Resource
    Electronic Resource
    Statistical entropy model for relaxation in stressed polymer glasses (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 915-920 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The molecular kinetic theory near the glass transition, bused on the existence of free volume distribution, is extended to incorporate the effects of stress and stress rate. The fundamental equations for the volume relaxation and recovery in stressed amorphous polymers are derived in accordance with the balance of nonequilibrium statistical entropy. Using these kinetic equations, an earlier nonequilibrium criterion for the glass transition temperature, Tg, is generalized to include the effects of stress and stress rate. In contrast to the prevalent thinking toward free volume theories, an explicit expression between Tg and stress is developed and reveals that Tg does not continue to increase at all pressures but levels off to a “universal” asymptote at very high pressure (〉10 K bars). The expression is applicable to any tension and compression stress conditions. A comparison between theory and experiment under constant stresses determines the activation volume tensor which reveals the molecular mechanism relating Tg and the plastic yield of glassy polymers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241111
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  • 111
    Electronic Resource
    Electronic Resource
    Evaluation of paper properties of thermomechanical pulp modified by ozonation and grafting with thermoplastic polymersPresented at Second World Congress of Chemical Engineering, Montréal, Canada, Oct. 4-9, 1981 (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 950-955 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Paper properties of the thermochemical pulp modified by ozonation and grafting with styrene, acrylamide or their mixtures have been studied. Paper sheets, prepared by hot pressing from ozonated and grafted pulps showed improvement in: wet breaking length; dry breaking length; burst and dimensional stability.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241203
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  • 112
    Electronic Resource
    Electronic Resource
    Binary blends containing a commercial polyarylate (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 608-611 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A commercial polyarylate (PAr), a copolyester of Bisphenol-A with 50 percent terephthalate-50 percent isophthalate, has been characterized by means of a combination of gel permeation chromatography and viscometry. It has been studied as first component of a series of polymer blends. The presence of either one glass transition temperature (Tg) or two has been used as a criterion to determine the miscibility of each blend. In some cases, the possible incidence of transesterification reactions has been considered.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240813
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  • 113
    Electronic Resource
    Electronic Resource
    The archimedean screw as an extruder; historical note (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 624-625 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240903
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  • 114
    Electronic Resource
    Electronic Resource
    Residence time distribution in a twin screw extruder (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 645-651 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The residence time distribution (RTD) in a fully intermeshing, corotating twin screw extruder was determined with a stimulus-response technique. In addition to varying three process parameters (i.e. throughput, screw rotational speed, and barrel temperature), two screw configurations were also studied: one containing four kneading block mixing sections, and the other consisting only of regular screw bushings. Although screw configuration was an important variable, it was found that for both configurations the throughput had the largest effect on RTD. The screw rotational speed was second in importance, and the barrel temperature change produced no effect.A fluid mechanical model based on the fluid flow in a partially-filled rectangular channel was used to explain the experimentally observed dependence of RTD on the process parameters. Reaction engineering approaches were adopted to compare the RTD results of two screw configurations with two idealized flows.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240906
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  • 115
    Electronic Resource
    Electronic Resource
    A study in injection molding dynamics (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 686-691 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Some aspects of injection-molding dynamics were studied using a laboratory injection-molding machine operated under the control of a microprocessor-based servocontrol system. Two types of experiments were performed: deterministic tests which introduced step changes in the servovalve opening and stochastic tests using pseudo-random binary sequence (PRBS) perturbations of the servovalve. Deterministic models were written for the hydraulic and nozzle pressures which were in good agreement with the experimental data. A stochastic transfer function-noise model was obtained for the nozzle pressure, but an adequate model was not found for the hydraulic pressure. The agreement between the nozzle pressure stochastic model and the corresponding step test model was satisfactory.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240910
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  • 116
    Electronic Resource
    Electronic Resource
    Numerical simulation of entry and exit flows in slit dies (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 707-715 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A general-purpose finite element program has been used to simulate the flow of Newtonian, power-law, and viscoelastic fluids in the entry and exit regions of a slit die. It was found that shear-thinning increases the entrance correction while it decreases the exit correction. Shear-thinning reduces the size of the small corner vortex that forms in the entry flow of a Newtonian fluid. The swelling ratio had a value of 1.196 for Newtonian fluids and decreased as the value of the power-law index decreased. Viscoelastic calculations were performed using the Criminale-Ericksen-Filbey (CEF) constitutive equation. Convergence of the iterative scheme was unattainable for Deborah numbers above 1.0. The results showed a decrease of the entrance correction and an increase of the exit correction with elasticity. Extrudate swell first decreased slightly and further increased with the Deborah number.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240913
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  • 117
    Electronic Resource
    Electronic Resource
    Craze fibril formation and breakdown (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 761-769 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: As crazes grow in areal extent they also increase in width. The areal growth involves craze tip advance which has been shown to occur by the Taylor meniscus instability. Craze widening, at least for air crazes, occurs by drawing more fibrillar material from the craze-bulk polymer interfaces at essentially constant extension ratio. Simple arguments will be given to predict the scale of the fibrillation in terms of the stress S at the craze tip and interfaces and an effective polymer surface energy (Γ) where:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\Gamma = \gamma + {\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 4$}}d \cdot v_E U_b} $$\end{document} which assumes that all entangled chain crossing the surface are broken [γ represents the van-der-Waals (intermolecular) surface energy, d is the entanglement mesh size, vE is the entanglement density, and Ub is the energy required to break a single backbone bond]. These arguments also give the rate of fibrillation as a function of S, a nominal plastic resistance σy and Γ and can explain the fact that the stress for crazing increases relative to that for shear deformation as the entanglement density of the polymer is increased. The geometrically necessary entanglement loss (either by scission as assumed above or by disentanglement- at temperatures just below Tg) that accompanies fibril formation has important consequences for fibril stability. The probability p that a given entangled chain is lost can be computed from simple geometrical considerations knowing the fibril diameter D, its extension ratio λ and the mesh size d; p increases rapidly as Dλ½ becomes comparable to or less than d. These concepts can be tested in blends of high molecular weight polymer with chains of the same polymer that are too short to entangle.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241006
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  • 118
    Electronic Resource
    Electronic Resource
    Anisotropic aspects of the environmental stress cracking of acrylonitrile-butadiene-styrene and styrene acrylonitrile copolymers in methanol (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1174-1179 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Critical strains causing environmental stress cracking of injection-molded poly(acrylonitrile-butadiene-styrene) (ABS) and poly(styrene-acrylonitrile) (SAN) plaques were determined upon exposure to methanol. Measurements were obtained for samples strained either parallel or perpendicular to the melt flow direction and for samples located at various distances from the mold gate. Critical strains were significantly higher in the direction parallel to the melt flow compared to the transverse direction. The degree of anisotropy increased with increasing rubber content. For ABS containing 46 percent rubber, the critical strain at one point was determined to be 2.99 percent in the direction of melt flow, but only 0.47 percent in the orthogonal direction. For this material, critical strains determined parallel to the melt flow decreased with distance from the gate; whereas, critical strains for SAN and ABS containing 30 percent rubber remained essentially constant. Orientation of the plaques was assessed using shrinkage determinations and a thermal conductivity technique. Though a straightforward correlation of orientation with critical strain is observed for ABS, a similar relationship is not observed for SAN. These results suggest that although stress cracking occurs in the glassy matrix of ABS, it is the dispersed rubbery phase which controls the magnitude of strain required to initiate cracking.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241506
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  • 119
    Electronic Resource
    Electronic Resource
    Kinematics, dynamics and stability of the tubular film extrusion of various polyethylenes (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1185-1201 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A basic study of the kinematics, dynamics, and heat transfer occuring during tubular film extrusion of polyethylene is outlined. Three rheologically characterized polyethylenes, a low-density polyethylene (LDPE), a linear-low-density polyethylene (L-LDPE), and a high-density polyethylene (HDPE) were used in this study. The kinematics and stability of the tubular film process were investigated over a wide range of blow-up ratios, drawdown ratios, and frost-line heights. Local deformation rates along the bubble have been determined. Regions of stability and instability are described. Tensions and inflation pressures have been measured and expressed in terms of locol elongational viscosities. Temperature profiles along the bubble were determined and interpreted in terms of local heat transfer coefficients. Positions of crystallization and temperature profiles have been noted and used to estimate rates of crystallization. The characteristics of the LDPE, LLDPE, and HDPE are contrasted.
    Additional Material: 47 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241508
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  • 120
    Electronic Resource
    Electronic Resource
    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241601
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  • 121
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    Correction (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1020-1020 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241303
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  • 122
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    A study of the dynamics of foam growth: Analysis of the growth of closely spaced spherical bubbles (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1026-1034 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A mathematical analysis of bubble growth in an expanding foam is presented. The analysis is based on a cell model whereby the foam is divided into spherical microscopic unit cells of equal and constant mass, each consisting of a liquid envelope (or shell) and a concentric spherical gas bubble. Expansion occurs by diffusion of a dissolved gas from the supersaturated envelope into the bubble. This cell model is capable of describing important qualitative features of a real system of numerous bubbles growing in close proximity to one another, and is intended as the building block of a global analysis of macroscopic foam expansion. The coupled algebraic and differential equations governing the growth of a cell are derived and solved numerically. Five dimensionless parameters are identified for the case of constant temperature and pressure outside the cell, and their effects are demonstrated through computer simulations of the system. Of these parameters, surface tension and initial radius prove to be of relatively little importance in the practical cases considered. The other parameters are the thermodynamic driving force, the cell mass (inversely proportional to the number density of bubbles), and the ratio of characteristic times for mass and momentum transport.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241306
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  • 123
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    Measurement of mixing in polymer melts by focused ultrasound (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1277-1282 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper outlines the development of an acoustical technique for measuring the dispersion of an additive in a polymer melt. It included a justification of the use of sound over other interrogating methods and an analysis of the acoustical system's operation. Results for dispersions of liquid or solid additives were shown. It was demonstrated that this system could detect the presence or absence of large particles in melts filled with small particles.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241611
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  • 124
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241701
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  • 125
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    Statistical thermodynamics of blends: Equation of state and phase relations (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1284-1290 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We 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 ΔGm represents a difference between large quantities. As illustrations we analyze two typical systems. One is the n - C6 + n - C16 pair where PVT and ΔGm, the latter at atmospheric pressure only, have been studied experimentally. The other is n - C6 with 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 regarding polymer blends.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760241703
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  • 126
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    Polycarbonate blends with polystyrene and polypropylene (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1312-1318 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Blends 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.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241708
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  • 127
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    Development of phase morphology in incompatible polymer blends during mixing and its variation in extrusionThe experimental studies described were carried out at the University of Tennessee as part of the Ph.D. Dissertation of K. Min. (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1327-1336 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An 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 discussed.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241710
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  • 128
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240101
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  • 129
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    Improved bending fatigue life of Kevlar 29 braid by the use of an impregnating medium (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 42-47 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Kevlar 29 fiber has been widely considered for the manufacture of very-long high-performance cables. Due to low transverse strength fiber-on-fiber rubbing leads to rapid deterioration. The usefulness of impregnating Kevlar 29 braids with resin to overcome this drawback has been evaluated by performing reverse bending fatigue tests. Braids of identical construction, one of them being impregnated with a polyurethane resin by a patented process, were fatigued to failure on a purpose-built rig under varying applied loads. Fatigue tests were also carried out to 30 percent and 50 percent of total braid life and residual strength values measured. It was found that high applied loads (∼50 percent of ultimate) lead to premature braid failure dominated by a creep mechanism. Both braids showed similar behavior, although the impregnated braid was superior. At low applied loads, however, where the failure mechanisms was dominated by wear or internal abrasion, it was seen that resin impregnation could increase braid life by a factor of four. Resin impregnation coupled with bending fatigue significantly stiffens braids, as was demonstrated by tensile testing up to braid failure.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240105
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  • 130
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    The apparent rate constant model for kinetics of radical chain copolymerization: Chemical-controlled process (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 22-29 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In this article the kinetics of chemical-controlled radical-chain copolymerization have been reduced to pseudohomopolymerization kinetics by introducing the apparent rate constants, The methods for the determinations of the values of the apparent rate constants, mode of termination, and the methods for the calculation of molecular weights and distributions are proposed. The data required for these determinations and calculations are simply obtained by the usual steady-state method. According to the traditional kinetics along with the definitions of the apparent rate constants, these apparent rate constants as functions of traditional rate constants, monomer compositions, and copolymer compositions are derived. Further utilizing the theoretical expressions obtained, we show that the apparent rate constants are the general rate constants for both radical chain homo- and copolymerizations. The bulk radical copolymerizations of methyl methacrylate and styrene at various monomer feed compositions at 60°C are used to test the proposed model. The empirical apparent rate constants obtained are described well, by the following expressions, \documentclass{article}\pagestyle{empty}\begin{document}$$ \beta = 0.997{\rm }F_1 + 0.398{\rm }F_2 + 0.039\left({F_1 F_2 } \right)^{\frac{1}{2}} $$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$$ {{k_t^a } \mathord{\left/ {\vphantom {{k_t^a} {\left({k_p^a} \right)}}} \right. \kern-\nulldelimiterspace} {\left({k_p^a } \right)}}^2 = - 0.138 \times 10^4 \left({{{F_1 } \mathord{\left/ {\vphantom {{F_1 } {f_1 }}} \right. \kern-\nulldelimiterspace} {f_1 }}} \right)^2 + 0.354 \times 10^4 \left({{{F_1 F_2 } \mathord{\left/ {\vphantom {{F_1 F_2 } {f_1 f_2 }}} \right. \kern-\nulldelimiterspace} {f_1 f_2 }}} \right) - 0.114 \times 10^4 \left({{{F_2 } \mathord{\left/ {\vphantom {{F_2 } {f_2 }}} \right. \kern-\nulldelimiterspace} {f_2 }}} \right)^2 $$\end{document} and the mode of termination on the combination termination is \documentclass{article}\pagestyle{empty}\begin{document}$$ {1 \mathord{\left/ {\vphantom {1 {{\rm k}_p^a = - 0.132}}} \right. \kern-\nulldelimiterspace} {{\rm k}_p^a = - 0.132}} \times 10^{ - 2} \left({{{F_1 } \mathord{\left/ {\vphantom {{F_1 } {f_1 }}} \right. \kern-\nulldelimiterspace} {f_1 }}} \right) + 0.428 \times 10^{ - 2} \left({{{F_2 } \mathord{\left/ {\vphantom {{F_2 } {f_2 }}} \right. \kern-\nulldelimiterspace} {f_2 }}} \right) $$\end{document} where Kaa and Kta denote the apparent rate constants of propagation and termination, respectively. The term f1(= 1 - f2) stands for the mole fraction of styrene in the monomer solution fed. F1 is the copolymer composition produced at f1. β is the mode of termination.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240103
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    Morphology - properties relationships in binary polyamide 6/rubber blends: Influence of the addition of a functionalized rubber (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 48-56 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The modification of an amorphous random ethylene-propylene rubbery copolymer (EPM) has been accomplished by solution grafting of maleic anhydride molecules promoted by radical initiators, The resulting EPM-g-succinic anhydride (EPM-g-SA) and EPM have been used to obtain binary polyamide 6/EPM or polyamide 6/EPM-g-SA and ternary polyamide 6/EPM/EPM-g-SA blends by melt mixing. The formation of an EPM-g-PA6 graft copolymer during the blend preparation has been assumed. Different blend morphologies were observed by scanning electron microscopy (SEM) according to the nature and content of the rubber used. The tensile mechanical properties and the impact behavior of the prepared blends were investigated and correlated with the SEM analysis of the fracture surfaces. Binary and ternary blends containing 20 percent by weight of total rubber show a significant improvement of the impact properties at low temperature (-20°C) when the rubber is partly or entirely EPM-g-SA. In the case of PA6/EPM-g-SA (80/20) blend these results are related to the presence of rubbery domains of very small size strongly adherent to the PA6 matrix. In the case of 80/10/10 ternary blends, a much more complicated overall morphology is observed. Such morphology is characterized by the presence of large EPM domains, likely containing some EPM-g-PA6 graft molecules acting as an interfacial agent, and domains of EPM-g-PA6 of smaller size strongly adherent to the matrix as in the previous case.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240106
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  • 132
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    Use of the lower critical solution temperature for the characterization of polymer mixtures and the study of their compatibility: Application to polyethylenes, polypropylene, and their copolymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 98-103 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The Lower Critical Solution Temperature (LCST) of polyethylene (PE), polypropylene (PP), and ethylene-propylene block and random copolymers have been measured in heptanes. A thermogram related to the variation of the turbidity of the solution is obtained between 100 and 210°C. The temperature of the onset of the turbidity peak is defined as the LCST of the system. The width and the area of the turbidity peaks are tentatively associated with the polymer polydispersity and the amount of polymer involved in the phase separation. The thermograms of solutions containing both homopolymers show two distinct turbidity peaks situated at a 70°C interval. Correlations of molecular orientations in the concentrated phase, possible in PE systems but not in PP solutions, are at the origin of the lower LCST values for PE solutions. The LCST of copolymers are situated between those of the homopolymers but the dependence of the LCST on the copolymer ethylene content is different for block and random copolymers. Examples of thermograms are also given for mixtures of copolymers with PE and PP. By analysis of their thermograms, some commercial block EP copolymers were also found to contain PK and PP. This method seems well suited for characterizing polymer mixtures.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240206
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  • 133
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    Dielectric properties of poly(α-methyl α-n-propyl-β-propiolactone)/poly(vinyl chloride) blends (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 144-152 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dielectric properties of miscible blends of poly(vinyl chloride) (PVC) and poly(α-methyl-α-n-propy-β-propiolae-tone) (PMPPL) have been investigated at different temperatures above and below Tg. The results were analyzed using the Cole-Cole representation and lead to the conclusion that this mixture does not exhibit micro-scale heterogeneities. Dielectric constant and dielectric loss master curves were constructed using the stress relaxation shift factors determined previously; the same shift factors could be used for the homopolymers and their blends. Similarities between the dielectric master curves and the stress relaxation master curves of PVC, PMPPL, and their blends, are also discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240212
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  • 134
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    Thermokinetics of unsaturated polyester and vinyl ester resins (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 175-184 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An experimental study was carried out to investigate the isothermal and non-isothermal curing kinetics of unsaturated polyester and vinyl ester resins, using differential scanning calorimetry (DSC). Emphasis was put on investigating the effect of low-profile additives on the curing kinetics of the thermo-setting resins. For the study, a general-purpose polyester resin and a vinyl ester resin were used, together with polyvinyl acetate (PVAc) as low-profile additive, benzoyl peroxide as initiator, and N,N-dimethyl aniline as promoter. It has been found that (1) the addition of the low-profile thermoplastic-additive decreases the rate of cure and, also, the final degree of cure of the resins, (2) the total heat of cure generated by isothermal cure is lower than that generated by non-isothermal cure, and (3) the resin/initiator mixture with promoter exhibits two major exotherm peaks during non-isothermal cure, but only a single exotherm peak during isothermal cure.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240304
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    Thermal expansion of oriented glassy polymersThis material was presented in part at the ACS 17th Middle Atlantic Regional Meeting. White Haven, Pa., April 6-8, 1983. (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 205-210 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A phenomenological model of entanglement networks is developed and applied to deformed glassy polymers. Thermal expansivities and birefringence are analyzed. The model assumes a stable network of entanglements up to draw ratios of about 5. Beyond that range the entanglement structure breaks down to maintain a nearly constant drawing stress. The results are used to determine the ultimate linear expansivities of atactic polystyrene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240307
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  • 136
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    The effect of a temperature gradient on residual stresses and distortion in injection moldings (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 227-241 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Distortion of bars injection-molded from polystyrene, polypropylene, and glass-fiber-filled polypropylene and subsequently placed in a temperature gradient has been examined. Residual stress distributions have been measured both for the as-molded state and after annealing in a temperature gradient. In the as-molded state all moldings showed the usual residual stress distribution with compressive stresses near the surface and tensile stresses in the interior. In all three materials it was found that tensile stresses could be developed near to the warmer surface on gradient annealing and that tensile stresses still remained at this surface when the bar was cooled and permitted to bend to restore internal equilibrium. It is shown therefore that in addition to the dimensional changes which occur and which may render the molding unserviceable after temperature gradient annealing, another undesirable change takes place, leaving the molding much more susceptible to fracture from a surface flaw. Uniform annealing is found to be much less likely to cause stress reversal and the stresses remain balanced so that distortion is minimal.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240402
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    Introductory remarks (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 519-519 
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    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240802
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    Mechanical compatibilization of immiscible blendsPresented at the International Symposium on Phase Relationships and Properties of Multicomponent Polymer Systems, Anacapri, Italy, May 30-June 3, 1983 (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 525-534 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanical properties of a variety of immiscible binary blends, with and without third component polymeric compatibilizers, are reviewed and qualitatively related to the degree of adhesion between blend components as determined by lap shear testing. Generally, blends comprised of components which adhere well, one to the other, show improved ductility relative to blends of components which do not adhere, Similarly, polymeric compatibilizers are found to be more effective for improving the properties of a binary blend system if they adhere well to both primary components of the immiscible mixture. These results suggest that adhesion between phases in the mixture strongly influences the ultimate properties of the blend. Some evidence is presented which suggests that components which adhere well are partially miscible.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240804
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  • 139
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    Bulk and surface thermodynamics of polymer alloys (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 598-600 
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    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper presents an overview of the subject of phase separation in polymer blends with an emphasis on the thermodynamic stability criteria for phase stability and the classical thermodynamic and microscopic description of polymer interfaces.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240811
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240901
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  • 141
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    Chain scission and mechanical degradation of polystyrene (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 421-427 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The extent of molecular degradation of amorphous polystyrene when subjected to mechanical grinding at cryogenic temperature has been investigated using electron spin resonance, infrared spectroscopy, and viscometry. Essentially identical concentrations of chain ruptures in the degraded samples were found from infrared spectroscopic determinations of molecular end group concentrations and by the changes in the viscosity-average molecular weights. The chain-scission concentration was from two to four times the free-radical concentrations, indicating that free-radical-propagation reactions play a much less dominant role in the degree of molecular damage associated with mechanically induced chain scission in glassy polymers. In addition, experiments were carried out as a function of molecular weight and these indicated a virtual independent behavior with molecular weight.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760240606
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    On the nature of polymer interfacesd and interphases (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 79-86 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An abbreviated review of the current state of knowledge of polymer interfacial phenomena is given. Classical thermodynamics treats the interfacial zone (the interphase) as a “black box” and yields rigorous relationships among interfacial quantities. A recent reformulation of interphase thermodynamics, which eliminates the use of a Gibbs dividing surface, is shown to be an invaluable tool for investigating interfacial properties. Microscopic theories, such as the gradient theory, yield more details about what is in the black box, but the information is only approximate. The gradient theory has been used to: (1) relate the surface tension of a polymer liquid to its isothermal compressibility, (2) develop a quantitative theory of polymer liquid surface tension, and (3) determine the interfacial tension between two immiscible polymer liquids. The gradient theory will be shown to be in harmony with the microscopic theory of Helfand and co-workers although the latter treats polymer interfaces from a completely different point of view.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240204
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  • 143
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    Rheological and heat-transfer considerations for the processing of reactive systems (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 698-706 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Thermosetting materials have found widespread use over a broad spectrum of engineering applications due to their intrinsic mechanical strength, thermal and dimensional stability, and other unique properties. Consideration is given to those aspects of reaction kinetics, rheology, fluid mechanics, and heat transfer which are of relevance for the mathematical modeling of reactive polymer processing. Particular emphasis is given to the characterization of reaction kinetics under non-isothermal conditions, the effect of fillers or reinforcing agents on the heat transfer and kinetic behavior, and the complex nature of the interactions brought about by the reactivity of these systems. In addition, the current status of the mathematical simulation of reactive polymer processing is briefly reviewed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240912
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    Foreword (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 843-843 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241102
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  • 145
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    Analysis of the evolution of microcreep during physical aging and mechanical deformation in poly(methyl methacrylate) using a microstructural model (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 921-929 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The evolution of poly(methyl methacrylate) (PMMA) during physical aging at 90°C is followed by torsional microcreep tests. On the aged specimen a longitudinal stress is applied which induces a strain of 5 percent after 30 days of creep. The torsional microcreep tests are performed during the longitudinal creep in order to compare the structure evolution of PMMA caused by straining with its evolution measured during aging. The microcreep, for the first 800s, follows a reversible logarithmic law. In this stage the mobile defects achieve their activated form which is perfectly reversible when unloaded. The physical aging reduces this logarithmic part of microcreep. This is due to the decrease of either the number or the volume of the mobile defects. Beyond a critical elongation ∊ = 1 percent, the longitudinal straining has just the opposite influence, i.e., the logarithmic part of microcreep increases. This critical elongation ∊ = 1 percent corresponds to the beginning of the steady state longitudinal creep. The transient that precedes this steady state has no detectable influence on the structure of the specimen.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241112
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241201
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  • 147
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    Concerning voids in polyimide (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 345-349 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Small angle X-ray scattering (SAXS) has been used to evaluate the size and concentration of voids in poly(N,N′-bis-(phenoxyphenyl)pyromellitimide), PMDA-ODA. Analysis of the angular dependence of the scattering indicates the presence of voids ranging from 50 to 150 Å in radius. Integrated SAXS demonstrated that the volume fraction of voids was 7 × 10-4. These results were supported by measurements of the attenuation factor as a function of the sample thickness.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240508
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  • 148
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240601
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  • 149
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    Effects of thermal history on structural recovery of glasses during isobaric heating (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1087-1103 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The response of glass-forming systems to isobaric three-step thermal cycles involving cooling, isothermal annealing, and subsequent reheating has been investigated comprehensively using numerous combinations of the experimental and material parameters. The latter include the retardation spectrum or response function and the parameter x which determines the relative contributions of temperature and structure to the retardation times. The results show that, on heating, multiparameter systems can display three kinds of peak in the expansion coefficient α or the heat capacity Cp originating from the interactions of the elementary retardation processes with the thermal history of the glass. The conditions under which these peaks occur, their shifts with x, and the experimental variables have been investigated in detail. In particular, it has been shown that for a thoroughly stabilized glass reheated rapidly, the temperature at which the main peak occurs is strongly dependent on the experimental variables and on x, and that this dependence can lead to an estimate of the value of x. For poorly stabilized glasses reheated slowly, on the other hand, the main peak apparently vanishes and allows an upper peak to appear, which is small and insensitive to x and the experimental variables. Intermediate situations in which the main and the upper peaks occur separately give rise to a range of effects which may become quite complicated as the two peaks approach each other. The occurrence of such multiple peaks, which has usually been overlooked or misinterpreted in the past, is discussed and explained in detail and is compared with some experimental observations reported in the literature.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241404
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  • 150
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    Spectroscopic observations on nonequilibrium glassy poly(vinyl chloride) and polystyrene (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1130-1137 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The relationship of valence-coordinate deformation to the temperature dependence of some infrared peak-absorption frequencies in Poly(vinyl chloride) (PVC) and polystyrene (PS) is stated. A skeletal band and a CH2 rocking band in PVC and a ring-mode band in PS were studied in two kinds of experiments: steady heating and cooling of a quenched (nonequilibrium, glassy) sample through its glass-transition temperature, Tg, and long-term annealing of quenched samples below Tg, followed by steady heating and cooling. The results, a slope discontinuity, ΔM, in the v(T) relation at Tg and a frequency shift, Δviso, during isothermal annealing below Tg, are analyzed in two theoretical approaches. Interchain and intrachain contributions to the observed frequency shifts are expected to occur with a differing relative significance in different kinds of molecular vibrations, leading to one possible method of distinguishing valence-coordinate deformation (chain strain) from other effects.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241409
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  • 151
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    Rheological and mechanical behavior of the UHMWPE/MDPE mixtures (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 117-126 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An attempt was made to melt incorporate ultra high molecular weight polyethylene, UHMWPE, into medium density polyethylene, MDPE. The behavior of the mixtures, containing up to 6 wt percent of UHMWPE, was examined using mechanical and rheological testing. The mechanical test results were found to contain large experimental errors, which makes interpretation very difficult. On the other hand, melt rheology studies, using dynamic and extensional deformations, gave direct insight into the extent and effect of blending. Degradation during the processing was evaluated by size exclusion chromatography. The degree of dispersion of the UHMWPE was examined under the optical microscope.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240209
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  • 152
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    Some observations on kinetic and steric limitations to specific interactions in miscible polymer blends (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 112-116 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This note describes the application of infrared spectroscopy to determine the proportion of ester groups of poly(∊-caprolac-tone) which are involved in specific interactions with the hydroxyl groups of the poly(2-hydroxypropyl ether of bisphenol A) (Phenoxy, Union Carbide) in a series of miscible blends of the two polymers, Even with a fifteen-fold excess of hydroxyl groups, only about 50 percent of the ester groups of poly(∊-caprolactone) are hydrogen-bonded, presumably reflecting steric restrictions to the ester-hydroxyl interactions. Partially miscible blends of these two polymers may also be prepared by a suitable choice of casting solvent, and infrared spectroscopy may then be used to follow the kinetics of miscibility when the partially miscible blend is heated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240208
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    Analysis of transient sorption and permeation of small molecules in multiphase polymer systems (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 153-162 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The transport of small molecules (gases) in incompatible polymer blends, semi-crystalline polymers, and filled polymer systems is usually examined in terms of transient sorption and permeation experiments which yield effective values of diffusivity and permeability. From a modeling standpoint these complex systems can be regarded as composites with complex morphology whereas the gas can be considered as a molecular probe of the morphology and especially its connectedness. In this paper we present a brief review of transport descriptions in prototype ordered and disordered systems with special emphasis on simulation of transient measurements. The simulations presented are selected in such a way as to aid in the interpretation of experimental results obtained by sorption and permeation and in the construction and evaluation of morphologies with desired effective transport properties.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240213
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  • 154
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    Optimization of the transesterification stage of polyethylene terephthalate reactors (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 185-193 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The tranesterification step of the polyethylene terephthalate (PET) formation consists of several side reactions in addition to the main ester interchange, transesterification, and polycondensation reactions. The side reactions considered in this work are acid end group, acetaldehyde, diethylene glycol, water, and vinyl end group formations. The objective function of the batch esterinterchange reactor is assumed to consist of maximizing the conversion and simultaneously minimizing the formation of side products. The control vector iteration procedure has been used to optimize the esterinterchange reactor and the temperature-time profile that gives the best performance has been found. It is found that the reactor should be operated at a high temperature initially to obtain high conversion of dimethyl terephthalate (DMT) first, but then it should be lowered to reduce the formation of side products.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240305
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  • 155
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    Hot water aging of polycarbonate (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 211-217 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Internal cracking and microvoids are shown to form during room temperature storage of polycarbonate samples that have previously been exposed to boiling water. These microcracks or microvoids are actually disc-shaped pockets filled with water. This formation occurs due to the creation of water super-saturation conditions by cooling water-saturated specimens from 100°C to room temperature. As a result, water phase-separation, clustering, and microvoiding result and lead to deterioration of the mechanical properties. Visual healing of the microcracks is also sometimes observed at room temperature, especially under a dry atmosphere. Water from the water-filled pockets diffuses through the polycarbonate matrix to the external dry environment; the very thin emptied pockets then close and visually heal. This paper provides experimental data for the microvoiding process and clarifies the special mechanism of cracking/healing in polycarbonate samples.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240308
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240401
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  • 157
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    Torsional braid analysis of bitumen-liquid rubber mixtures (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 252-258 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The performance of liquid rubbers as low-temperature plastcizers for bitumen was evaluated by the torsional braid technique developed by Gillham. The low-temperature dynamic mechanical properties of bitumen-liquid rubber mixtures were measured from ambient to -100°C and compared with the corresponding fracture behavior using a modified Fraass test. Microscopic observation of the mixture revealed that the liquid rubber was partially soluble in the bitumen at 23°C and at concentrations greater than 10 percent tended to form colloidal dispersions of rubber particles having mean diameters of approximately 10 μm. The loss tangent maxima shifted to lower temperatures and became less pronounced as the concentration of liquid polybutadiene increased. The colloidal rubber dispersion further contributed to the ductility and reduced the brittle temperature of the bitumen at -30°C at 20 percent liquid rubber concentration. The reduction in the brittle temperature of the bitumen is related to the glass-transition temperature of the added rubber, those rubbers having, the lowest glass-transition temperatures being most efficient. Such modifications are necessary to reduce the tendency of asphaltic paving materials to crack in cold climates.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240404
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  • 158
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    Free radical solution oligomerization of styrene in a continuous-stirred tank reactor train (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1253-1259 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: For free radical oligomerization of styrene, a scheme for calculating the molecular weight distribution and conversion in a continuous-stirred tank reactor (CSTR) train is developed, which also allows the calculation of molecular weight distribution (MWD) for batch reaction. Calculations show that under conventional or near dead-end condition: (1) increasing initial initiator concentration, reaction time and reaction temperature, and decreasing initial monomer concentration cause P̄n and P̄w to decrease and MWD to narrow; (2) increasing initial initiator concentration, reaction time and reaction temperature, and increasing monomer concentration cause monomer conversion to increase; (3) a single CSTR gives a lower rate of oligomer production, but a narrower MWD than does a batch reactor.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241608
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  • 159
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    The plasticization of an epoxy resin by dibutylphthalate and water (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1270-1276 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The glass-transition temperature of an epoxy resin cured at two different temperatures and plasticized with water and dibutylphthalate has been studied. Both modulus of elasticity and yield stress were measured as a function of temperature to determine the glass-transition temperature. Drying a saturated material appeared to restore the glass-transition temperature to its original value but some broadening of the transition occurred. The behavior of an undercured epoxy when saturated with water could not be predicted by theory. A substantial increase in the transition temperature was observed which may have been caused by the presence of water and an expanded structure.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241610
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  • 160
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    Correction (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1290-1290 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241704
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  • 161
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    Compatibilization of polyester/polyamide blends via catalytic ester-amide interchange reaction (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1300-1305 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In 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 and 13C nuclear magnetic resonance spectroscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241706
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  • 162
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    A study of aromatic polyester/chlorinated polymer blends (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 350-354 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A large number of studies have been devoted in recent years to the miscibility behavior of linear polyesters with chlorinated polymers, including poly(vinyl chloride) (PVC), chlorinated PVC, chlorinated poly(ethylenes), and copolymers of vinylidene chloride (Saran). However, similar studies with aromatic polyesters are lacking. It is the purpose of this paper to compare the properties of blends made of poly(ethylene terephthalate), poly(butylene terephthalate) or poly(hexamethylene terephthalate) and of various chlorinated polymers. It is shown that a high concentration of chlorine atoms is required to achieve miscibility. Moreover, there is a “miscibility window” in terms of the carbonyl concentration of polyesters, immiscibility being found for carbonyl concentrations outside this window, A similar behavior was observed before for linear polyester/chlorinated polymer blends and for polyester/polycarbonate blends. Solid state small-angle light scattering experiments were also conducted to follow the morphology of the blends as a function of composition. Spherulites were found but their size vary with composition.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240509
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  • 163
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    Behavior and properties of shear bands (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 750-760 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Some recent observations on shear bands in polymers are reviewed. These include intrinsic properties such as the mechanism of formation, the intersection of shear bands, the rate of propagation with and without obstacles, recovery of shear strain by annealing, and the stored energy in shear bands. Mechanical responses include the shear yielding criteria, reverse shear behavior and the Bauschinger effect, and the fracture of and at shear bands. Environmental effects include methanol transport in shear bands and in deformed poly(methvl methacrylate) in the region of mixed Fickian and case II behavior and methanol crazing of a shear banded material.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241005
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    Deformation modes and fatigue behavior in styrene-acrylonitrile and acrylonitrile-butadiene-styrene copolymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 786-797 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The performance of styrene-acrylonitrile copolymers under alternating stresses has been examined. Information has been obtained concerning the influence of acrylonitrile content and of molecular weight on thermal effects due to hysteresis, on cyclic lifetime to craze initiation, on average cycles to fracture, and on fatigue fracture surface morphology. The influence of an elastomeric second phase has been determined by comparing fatigue performance under comparable conditions of both styrene-acrylonitrile (SAN) and acrylonitrile-butadiene-styrene (ABS). The stress concentrating effects of the rubber particles cause earlier initiation of fatigue-induced damage and lower fatigue fracture resistance. The fatigue-induced specimen temperature rise is greater in ABS than SAN and it increases linearly with test frequency and as the square of the stress amplitude. The fracture surface morphology of ABS, which differs from that of unmodified SAN and also from that of rubber modified polystyrene, is discussed.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241008
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  • 165
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    Stress and displacement fields at the tip of a craze containing a crack (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 814-819 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Plane elasticity theory is utilized to obtain expressions for the stress and displacement fields at the tip of a craze containing a crack. The craze is modeled as a very thin elliptical inclusion with different elastic properties from hat of the surrounding bulk polymer. Problem is solved by superimposing the solution of a crack problem onto the solution for a uniformly loaded homogeneous craze. Invoking stress free boundary conditions on the crack surface provides a singular integral equation of Hilbert type with a unique solution. Contour lines of constant hydrostatic stress and constant maximum shear stress around the craze tip are shown graphically. These two stress combinations have played prominent roles in a number of proposed craze growth criteria. Results show that even for relatively long cracks within the craze, very little stress enhancement at the craze tip occurs. Only as the crack tip approaches the craze tip does the enhancement become significant, tending to drive the craze region ahead of the crack.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241011
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  • 166
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    The effect of high pressure on the mechanical behavior of short fiber composites (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 844-850 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Three types of pressure dependent deformation processes have been observed for the short glass fiber reinforced composites of poly(vinyl chloride) (PVC). A unique deformation behavior, observed for the first time, features a sharp drop in stress followed by shear yielding in the matrix. Competitive pressure dependent failure processes in the composites are strongly affected by “debonding” at the fiber-matrix interface. A new general pressure dependent yield criterion for PVC and its composites was elucidated.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241103
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  • 167
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    Impact modification of poly(vinyl chloride) with chlorinated polyethylene II. Irreversible deformation (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 877-885 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The mechanical behavior of chlorinated polyethylene (CPE)-modified poly(vinyl chloride) (PVC) has been determined. The nature of the irreversible deformation processes which are responsible for mechanical energy absorption has been investigated by optical and electron microscopic techniques. Addition of CPE results in a decrease in the shear band initiation stress and an increase in void density and stability. The crazing to shear banding transition is observed at a blend composition between 2 and 7 percent CPE at the strain rate employed. It has been established that voiding occurs in the CPE rubber phase. Voiding accounts for at least part of the increased energy absorption of the blend. The stability of the voids to coalescence and fracture is attributed to strong adherence of the CPE to the primary PVC particles.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241107
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  • 168
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    A novel hysteresis test for studying crazing and shear yielding in rubber-toughened polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 535-540 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Tensile, tensile impact, compact tension, and fatigue tests were carried out on ABS (acrylonitrile-butadiene-styrene), HIPS (high impact polystyrene), and toughened PMMA (poly(methyl methacrylate)). Dumbbell specimens machined from test pieces were then subjected to sinusoidal tension-compression cycling at low stress amplitudes. The HIPS specimens produced asymmetrical hysteresis loops characteristic of multiple crazing, whereas PMMA gave more symmetrical, regularly shaped, loops. The behavior of the ABS polymers varied with loading history. It was concluded that the hysteresis test provides a useful additional technique for studying deformation mechanisms, especially under conditions that do not readily permit volumetric measurements.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240805
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  • 169
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    Applications of polymer blends: Emphasis on recent advances (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 587-597 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the past decade, polymer blend technology has achieved an important position in the field of polymer science. With increased academic and industrial research interest, the application of polymer blend technology to commercial utility has grown significantly. This review on the applications of polymer blends will cover the major commercial blends in the categories of styrene-based polymer blends, poly(vinyl chloride) blends, polyacrylate blends, polyester and polycarbonate blends, polyolefin blends, elastomer blends, polyelectrolyte complexes, and interpenetrating polymer networks. New developments in polymer blend applications will be discussed in more detail. These systems include linear low-density polyethylene blends with either low- or high-density polyethylene, styrenemaleic anhydride terpolymer/ABS (acrylonitrile-butadiene-styrene) blends, polycarbonate/poly(butylene tetephthalate) blends, new PPO/polystyrene blends, and tetramethyl bisphenol A polycarbonate/impact polystyrene blends. Areas for future research to enhance the potential for polymer blend applications will be presented. The need for improved methods for predicting miscibility in polymer blends is discussed. Weldline strength is a major property deficiency of two-phase systems (even those with mechanical compatibility), and future research effort appears warranted to resolve this deficiency. The use of polymeric compatibilization additives to polymer blends has shown promise as a method to improve mechanical compatibility in phase-separated blends, and will be expected to be the subject of future research programs. Finally, the reuse of polymer scrap is discussed as a future application area for polymer blends. Unique applications recently proposed for polymer blends include immobilization of enzymes, permselective membranes, reverse osmosis membranes, selective ion-exchange systems, and medical applications using polyelectrolyte complexes.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240810
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    Polymer blends from polyurethane and poly(methyl methacrylate) by reaction injection molding (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 974-979 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The simultaneous production of polyurethane (PUR) and polymethyl methacrylate (PMMA), starting from a mixture of polyol, polyisocyanate, and vinyl monomer, results in 2-phase polymer alloys. A simultaneous crosslinking of the PMMA is unable to prevent phase separation during the curing reaction; interpenetrating polymer network (IPN) structures were not found, Grafting the PMMA onto the PUR through the incorporation of 2-hydroxyethylacrylate resulted in single-phase systems. Various material combinations did not show, with a relatively high PMMA content, any poorer properties than the straight PUR. A major advantage of incorporating low-viscosity vinyl monomers lies in the fact that high-viscosity polyurethane starting components that are otherwise difficult or impossible to process can be processed here without problem.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241206
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  • 171
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    Mathematical modeling of melting of polymers in a single-screw extruder (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 988-999 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper addresses the apparent controversy surrounding the role of the solid bed mechanics in the Maddock melting mechanism. It is demonstrated that the inability of the melting models based on the freely deformable solid bed concept to predict accurately the pressure gradients in the melting zone is not exclusively due to the highly simplified isothermal Newtonian treatment of the melt pool as presumed previously. This study has shown that when using a non isothermal non-Newtonian flow model for the melt pool, the freely deformable solid bed concept still results in unrealistically low pressure gradients while it may give good predictions of the melting rates. To the contrary, when a rigid solid bed is assumed, the pressure predictions tend to represent the experimental data more closely, whereas the theoretical melting rates seems to become less realistic. In view of the fact that both the freely deformable and the rigid solid bed concepts show such inconsistencies, it has been concluded that the mechanics governing the solids and melt transport in the melting zone require some additional examination, most notably, the influence of the constitutive behavior of the solid bed and of the cross-channel melt circulation around the solid bed, and possibly of the melting kinetics for semicrystalline polymers.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241208
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241401
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  • 173
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    Molecular kinetic theory of the glass transition (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1079-1086 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An overview of a new molecular kinetic theory of glass-transition phenomena is presented and experimental comparisons of its prediction for a variety of thermal and stress histories reviewed. The theory, which was developed in accordance with the balance of nonequilibrium statistical entropy, is shown to provide a unified interpretation of some recent models. The volume-relaxation process in amorphous polymers over the glass-transition region is regarded as the result of the collapse of a series of free volumes having different levels of energies of hole formation. An applied stress is shown to contribute to the variation of the entropy. An activation volume is introduced as a new tensorial extensive variable. The theory is applied to the phenomenon of physical aging in polymer glasses and shown to provide good quantitative agreement with the results of a well-known experiment on volume recovery of poly(vinyl acetate). This supports the underlying postulate of a fundamental link between the apparent relaxation time and the mean energy of hole formation, the distribution of relaxation times and the free-volume fractions. In contrast to the prevalent thinking toward free volume theories, an explicit expression between Tg and stress is presented and reveals that Tg does not continue to increase at all pressures but levels off to a semi universal asymptote at very high pressure. The calculated effect of stress rate is found to be in good agreement with dynamic viscoelastic measurements.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241403
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    Physical aging of heavy metal fluoride glasses - sub-Tg enthalpy relaxation in a ZrF4-BaF2-LaF3-AlF3 glass (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1117-1122 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The enthalpy changes during structural relaxation or physical aging of a 58ZrF4-33BaF2-5LaF3-4AlF3 (ZBLA) glass during annealing well below the glass-transition temperature have been studied using differential-scanning calorimetry at several sub-Tg temperatures. Substantial relaxation within the course of several hours was detected at temperatures as low as sixty degrees below Tg (585K). The relaxation process is extremely nonlinear and self-retarding. The time dependence of the enthalpy during the initial stages of annealing was modeled approximately using the Narayanaswamy-Tool approach. The structural-relaxation parameters obtained from this fit were used to predict rates of physical aging for rapidly cooled ZBLA glass at temperatures close to ambient.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241407
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  • 175
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    Changes in yield and deformation of polycarbonates caused by physical aging (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1142-1148 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Change in yield and deformation associated with physical aging was studied on a series of polycarbonates (bisphenol-A polycarbonate, polyestercarbonates, and phenolphthalein-bisphenol-A copolycarbonates) and a polysulfone. A combination of tensile and biaxial yield measurements, dynamical mechanical analysis, and high-resolution density measurements were performed. These data indicate that both free volume arguments and molecular entanglement arguments are inadequate for explaining the differences in large-scale deformation associated with physical aging for the polymers and the superiority of polyestercarbonates over the other resins. The local intramolecular and intermolecular conformation in the glassy state, as predicated by molecular structure, is apparently an important key to understanding physical aging in polycarbonate-type polymers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241411
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241501
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  • 177
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    Processing of composites with titanate coupling agents - a review (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1369-1382 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is proposed that titanium-derived coupling agents react with free protons at the inorganic interface to form organic monomolecular layers on the inorganic surface, which causes inorganic/organic phase compatibilization resulting in new composite property, catalysis, adhesion, and rheology performance standards. Processing techniques and rheology effects using titanates are discussed. The injection pressures of CaCO3, carbon black filled polystyrene, and glass-fiber, talc-filled poly(phenylene sulfide) are shown to be reduced 50 percent by use of cumyl phenyl type titanate. Adhesion effects are discussed in many composites such as epoxy/aluminum, acrylic/slate, carbon fiber/polyester, etc., followed by data showing significant property improvements in 1/16 inch milled glass fiber and Wollastonite RRIM urethane, printed circuit boards and amide and anhydride cured aramid fiber-reinforced epoxy.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241802
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  • 178
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    General treatment of polymer crystallization kinetics - Part 2. The kinetics of nonisothermal crystallization (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1402-1408 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The isothermal macrokinetic equation of polymer crystallization has been generalized to cover nonisothermal situations as well. The process of nonisothermal crystallization of poly(caproamide) has been studied experimentally. It is shown that the macrokinetic equation of the autocatalytic type can be used to solve both direct and inverse problems of nonisothermal polymer crystallization. Use of the inverse approach has made it possible to establish the value of the constants of the new kinetic equation. The general statement of the problem of nonisothermal crystallization of polymers in an inhomogeneous temperature field is considered. Inhomogeneous temperature and conversion fields have been calculated for model products of different sizes and configurations.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241806
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  • 179
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    Chemiluminescence apparatus and method for studying thermal oxidative stability of polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1421-1428 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A chemiluminescence multi-sample apparatus and method are described for determining polymer stability by measuring the intensity of the light emitted during thermal oxidation. Depending on the nature of a material analyzed the experiments are performed either under O2 atmosphere at a constant temperature or under N2 atmosphere at a constant heating rate. In the former case applicable to polypropylene (PP) and acrylonitrile-butadiene-styrene copolymers (ABS), parameters such as induction time and oxidation rate can be evaluated. In the latter case applicable to nylon and polyethylene terephthalate (PET), the extent of oxidation in a certain temperature region can be evaluated by measuring the area under the intensity of light - temperature curve. Along with providing a great deal of knowledge on thermal oxidative stability, the chemiluminescence approach gives the additional information concerning polymer quality. The appearance of the low-temperature pulses on the chemiluminescence curve observed before the onset of autocatalytic oxidation is associated with the history and processing of the sample and with the natural aging of the polymer.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241809
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  • 180
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    Orientation studies of poly(ethylene terephthalate) (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 376-384 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper discusses the results of a detailed study of the relationships between molecular orientation, physical properties, and molecular weight of polyethylene terephthalate (PET), and their dependence on orientation variables. The molecular weight range of the samples used in this study included weight average molecular weights, Mw, between 29,000 and 65,000 which correspond to inherent viscosities, I.V., from 0.5 to 0.9. The orientation temperatures investigated were between 80 and 120°C. The extent of molecular ordering imparted by the orientation process was studied by birefringence, density, light scattering, and depolarized light intensity techniques. The results show that the degree of molecular orientation and the physical properties are strongly dependent on strain rate, extension ratio, molecular weight, and orientation temperature. The mechanical and transport properties, of PET are directly related to the degree of orientation as measured by birefringence. It is found that at a comparable level of orientation, the mechanical properties are also dependent on molecular weight, whereas the transport properties are independent of molecular weight. The degree of orientation varies according to the molecular weight of PET and stretch temperature. It is shown that for the same stretch ratio and stretch speed, the birefringence decreases with increasing stretch temperature. The light scattering results indicate that biaxial orientation of PET can lead to strain-induced crystallization. The amount and form of the crystalline structures are dependent on strain rate and orientation temperature.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240513
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    Molecular orientation in film extrusion of high-density polyethylene (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 415-420 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Molecular orientation in film extrusion has been studied using an extrusion-grade commercial polyethylene resin. First quad (take-up) speed was varied over the range 50 to 120 m/min, Web crystallinities were found to be in the range 0.60 to 0.65 as determined by differential scanning calorimetry. Web crystalline orientation function fc was slightly negative below a takeup speed of 50 m/min and rose to a value of 0.4 at 120 m/min at a quench bath temperature of 37.8°C and a melt temperature of 251°C for one of the resins used. (Perfect orientation along the machine direction implies fc equal to 1.0). Amorphous orientation function fa remained below 0.1 and was almost constant with takeup speed. This behavior was modified in a minor way by changes in quench bath and melt temperature as well as resin lot. A qualitative model was proposed for this without definite proof. The major mechanism at work in the film-forming process is macromolecular network structure deformation in elongational flow. Die gap variation at uniform extrusion rate has a secondary effect on web orientation. With the present state of knowledge, it is not possible to quantitatively separate the amorphous orientation function into its various conformational contributions. It was also noted that high take up speeds and low air gaps tend to freeze the web at greater widths.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240605
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240701
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  • 183
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    Tensile behavior of high-density thermosetting polyester foams (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 469-472 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This paper shows that the tensile properties of high-density stiff foams having cellular structures consisting of spherical voids can be described and predicted by simple rules. These rules are derived from other known and experimentally established relationships describing particulate systems of continuous glassy matrices containing a uniform dispersion of solid glass beads.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240704
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  • 184
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    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240801
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  • 185
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    Electronic Resource
    Heat transfer in injection molding of crystallizable polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 692-697 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A model is proposed for the treatment of heat transfer with crystallization during plastics processing in general, and injection molding in particular. The model incorporates experimentally determined crystallization kinetics parameters. It permits the calculation of the distribution of both temperature and crystallinity in the molding. Theoretical predictions are in good agreement with experimental measurements in both injection molding and a prototype apparatus.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760240911
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  • 186
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    Foreword (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 723-723 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241002
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  • 187
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    Electronic Resource
    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241001
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  • 188
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    Electronic Resource
    Microstructural aspects of failure in semicrystalline polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 770-785 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Microstructural features of semicrystalline polymers are reviewed, as are the roles of chain properties and thermal history in their development. Experimental results relating failure properties to microstructural detail are described. General models to explain inter- and intra-spherulitic failure behavior are proposed. Important are (a) the role of spherulite size in boundary incompatibility, (b) competition between spherulite boundary cracking and intraspherulitic yielding, (c) competition between localized (interspherulitic) fracture and dispersed (intraspherulitic) fracture.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241007
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  • 189
    Electronic Resource
    Electronic Resource
    Craze failure by midrib creep (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 809-813 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It has been known for some time that crazes thicken during growth mainly by drawing in fresh material from the craze-bulk interface, keeping the average craze fibril draw ratio approximately constant. Since Creep effects contribute only negligibly to craze growth rates these effects have generally been considered unimportant regarding craze breakdown. However, it is also known that the first stage of fracture is failure of the craze midrib, which is a highly drawn, very thin region down the middle of a craze. Because of the very low thickness of the midrib it has little influence on craze behavior, and information on midrib behavior is difficult to obtain. It is the purpose of this paper to attempt to rationalize what information is available.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241010
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  • 190
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    Electronic Resource
    Masthead (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241101
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  • 191
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    Electronic Resource
    High strain-rate shear deformation of a polyurethane elastomer subjected to impact loading (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 851-861 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Experimental techniques have been developed to produce and measure large amplitude one dimensional compression and shear waves in a polyurethane elastomer (Solithane 113). Experimental measurements consisted of time-resolved compression and shear amplitude measurements at different distances from the impact surface. The data were analyzed to provide compression and shear wave velocities, and the corresponding stress-stain curves on the microsecond time scale. The ability to measure directly the high stain rate shear response is a new development and has provided interesting results. The shear modulus varies between 3 and 9 kbar for compressive stresses ranging between 2 and 14 kbar. In contrast, shear modulus values inferred from quasi-static measurements of bulk and Young's modulus under static high pressure are negligible. These comparisons suggest a high rate dependence of shear modulus in the glassy state. The shear strain curves suggest an elastic-plastic response with yield strengths ranging from 0.12 kbar to 0.25 kbar with increasing compression for the compressive stress range investigated. Results of compression experiments are also presented.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241104
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  • 192
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    Electronic Resource
    Impact modification of poly(vinyl chloride) with chlorinated polyethylene I. Blend morphology (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 869-876 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The solid state morphology of chlorinated polyethylene (CPE)-modified poly(vinyl chloride) (PVC) and the relationship of blend structure to impact strength and mode of fracture have been investigated. Selective staining of the CPE phase showed that the morphology of the two phase system changes with increasing CPE content from a dispersion of discrete CPE particles to a network structure enveloping the primary PVC particles. The network formation coincides with a transition from brittle to ductile impact fracture. When the blend was mixed for too long a time or above the fusion temperature of the primary PVC particles, the CPE network was destroyed. The resulting indistinct domain structure is associated with a reduction in the impact properties.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241106
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  • 193
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    Electronic Resource
    Thermodynamic behavior of solid polymers in uniaxial deformation (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 908-914 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The heat and work of uniaxial deformation were measured for two commercial polyurethane elastomers and a low density polyethylene using a new deformation calorimeter. Internal energy changes in the materials resulting from deformation were calculated from the difference between the heat and work according to the first law of thermodynamics. The elastomers were found to exhibit complete reversibility for small and large strain deformation cycles as determined from the absence of a permanent internal energy change, even though one of these undergoes strain-induced crystallization and melting. The low density polyethylene behaves irreversibly even at small strains, and will store 30 percent of the deformation work as internal energy during drawing at room temperature.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241110
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  • 194
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    Electronic Resource
    Deformation behavior of plasticized poly(vinyl chloride) membranes with barium content (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 936-940 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Barium complexes were embedded in plasticized poly(vinyl chloride) (PVC) membranes. Effects of these metallic complexes were followed as a function temperature and strain rate. It was found that both the elastic modulus and yield stress decrease with barium content. This behavior is attributed to a lack of uniform structure and the existence of irregularities and voids in the bulk membranes. Another factor which may reduce the tensile strength is te internal and interfacial residual stresses developed at the metal-matrix interface. These internal stresses and the structural nonuniformity influence the electrical conduction mechanism and performance of the PVC matrix ion-selective electrodes during aging. Also, it was observed that the yield stress of these membranes has a strain rate and temperature dependence.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241114
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  • 195
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    Electronic Resource
    Orientation in amorphous polymers I. Preparation and testing of oriented samples (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 956-964 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Orientation effects in amorphous polystyrene are studied using a uniaxial stretching experiment. The rheological properties of the polymer are determined from an analysis of creep data obtained from the tensile apparatus, and oriented polymer samples are prepared at different extension ratios and rates of stretching. From birefringence and tensile strength measurements on oriented samples of polystyrene, it is shown that the tensile strength is not a unique function of the birefringence. It is proposed that the tensile strength may depend not only on the average orientation, as reflected by the birefringence, but on which portion of the relaxation spectrum is preferentially oriented.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241204
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  • 196
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    Electronic Resource
    Thermal conductivity and thermal expansion behavior of glass fiber-reinforced rigid polyurethane foam (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 943-949 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermal conductivities and the thermal expansion curves of glass fiber-reinforced rigid polyurethane foams with various fiber lengths, various fiber volume fractions and various matrix densities were determined experimentally. Additionally the thermal expansion coefficients of these materials at room temperature were examined in terms of the interaction between fiber and matrix. The thermal expansion properties were analyzed successfully with the analogous treatment which is applied to the mechanical tensile behavior.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241202
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  • 197
    Electronic Resource
    Electronic Resource
    Stress relaxation of glass-fiber-reinforced rigid polyurethane foam (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1000-1005 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Flexural stress relaxations were measured for rigid polyurethane foams (PUF) and glass-fiber-reinforced rigid polyurethane foams (FRU). The results were successfully analyzed in terms of the five element Maxwell model: (1) Samples reinforced with longer fibers exhibit reduced stress relaxation and reduced temperature dependency of stress relaxation; (2) The increased expansion ratio reduces the flexural modulus of both reinforced and non-reinforced materials, but the stress relaxation tends to increase greatly at the higher temperature for PUF, while not so greatly for FRU; (3) The temperature dependency of E1 decreases as longer fibers are used to reinforce the polyurethane. The dependency is minimal for the polyurethane reinforced with continuous fibers, where the reinforcing effect is maximal; and (4) The activation energy calculated from τ2 according to the Arrhenius plot is smaller for the longer fiber reinforced polyurethane foams.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241209
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  • 198
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    Electronic Resource
    Mechano-chemical degradation and stabilization of polymersBased on an invited lecture to the IUPAC Conference, Amherst, Massachusetts July 1982 (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1007-1020 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: When polymers are subjected to sheer, macroalkyl radicals are formed which lead to accelerated oxidation. This may occur in the polymer melt during processing or under conditions of mechanical fatigue at lower temperatures (e.g., in cross-linked rubbers). Under these conditions, chain-breaking electron acceptor (CB-A) antioxidants are found to be relatively more effective than under conditions of thermal oxidation and the evidence suggests that the reduced and oxidized couples of some antioxidants, for example, phenol/phenoxyl or hydroxylamine/nitroxyl, can deactivate radicals catalytically.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241302
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  • 199
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    Electronic Resource
    Surface-modified kevlar fiber-reinforced ionomer: Dynamic mechanical properties and their interpretation (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1047-1050 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A quasi-three-dimensional model was applied to the composite of ionomer and isotropically oriented discontinuous poly(p-phenylene terephthalamide) (PPTA) fibers having the surface modified by carboxymethyl groups in order to predict the Young's modulus from the properties of the constituent materials over a wide temperature range. The model in which the modified PPTA fibers are dispersed in ionomer matrix in a three-dimensional network is composed of series and parallel models. A good agreement between calculated and experimental values was eventually obtained. For comparision, the complex modulus of the composite was also evaluated by application of the Halpin-Tsai equation modified by Nielsen. The calculated values agreed with the observed values below 240 K, whereas the calculated values above 260 K were significantly lower than the observed moduli.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241309
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  • 200
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    Kinetic analysis of the data on the effect of humidity on the stability of poly(butylene terephthalate) (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1043-1046 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of temperature and humidity on polymer aging is well recognized. Gardner and Martin and Kelleher, et al., have collected extensive data on the effect of temperature and humidity during the course of aging of poly(butylene terephthalate) (PBT). They proposed an empirical equation to predict the half-life of aging. In the present work the data of Gardner and Martin have been reanalyzed to evolve an empirical equation which is applicable to the entire range of changes during aging.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241308
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