摘要:

AbstractPolyphenylene oxide was surface‐sulfonated with chlorosulfonic acid to provide antistatic properties. Optimal treatment time was shown to be 2–3 mins with a saturated solution of the acid in hexane or 25–30 mins using acid vapor‐saturated air under the given experimental conditions at room temperature. Being sensitive to humidity, the resistivity of the treated surface was lowered to the magnitude of 107to 108ohm/square at 43 percent relative humidity and to 1011at 10 percent relative humidity. The vapor phase method was found to be superior to the solution method with respect to the durability of the treated surface against water washing. Microscopic examination revealed extensive surface erosion by the solution tr

ISSN:0032-3888    

DOI:10.1002/pen.760160602

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractCalculation of the elastic constants of a participate composite material in terms of the elastic constants of the filler and the matrix is discussed. The theories of Kerner or Hashin and Shtrikman, the equivalent theories of Budiansky and Hill, and a generalized van der Poel type theory are presented and discussed. Data from several sources are compared with the predictions of these theories. The van der Poel theory provides the best agreement and gives good values for volume fractions of filler up to 0.35.

ISSN:0032-3888    

DOI:10.1002/pen.760160603

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe rate and temperature dependent fracture behavior of glass‐filled polystyrene has been investigated over the crack speed range of 1013to 1 mm/sec and in the temperature range 283 to 396°K for three environmental conditions: (i) air; (ii) water; and (iii) hot water exposure at 363°K and subsequent drying. Relationships between fracture toughness (Kc), crack speed and temperature have been obtained experimentally and analysed according to the concepts of fracture mechanics and reaction rate theories. Crack propagation in air is shown to be controlled by a β‐relaxation process associated with crazing. Activation energies of 200 ∼ 210 kj/mole in air and 80 ∼ 120 kj/mole in water are reported. At a given temperature and crack speed, the glass‐filled polystyrene is shown to display smaller crack propagation resistances in a water environment when compared with the air results. Specimens subjected to hot water exposure and then tested after drying also possess less cracking resistance. This toughness degradation phenomenon is a result of the damaging effects of the water which penetrates into the glass‐fi

ISSN:0032-3888    

DOI:10.1002/pen.760160604

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

Abstract“Hard elastic” polypropylene fibers respond nonlinearly to stress at all strains. Low tenacities at break (less than 1 g/denier), low moduli of elasticity (slopes of stress‐strain curves from 2.8 to 28 g/denier), and large breaking extensions (over 800 percent) are characteristic of “hard elastic” fibers. Behavior in simple extension, cyclic extension, and stress relaxation can be represented by a quasi‐linear viscoelastic model which uses a continuous relaxation spectrum and a quasilinear relation between stress historyT(t)and strain history λ(t):\documentclass{article}\pagestyle{empty}\begin{document}$$ T(t) = T^e [\lambda (t)] + \int_0^t {T^e [\lambda (\tau)]\dot G(t - \tau){\rm d}\tau } $$\end{document}whereTe[λ(t)] is the elastic response. When creep data are available, this model should provide a unified representation of experimental

ISSN:0032-3888    

DOI:10.1002/pen.760160605

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe melt bon debility of ethyl en e copolymers to a high, pressure polyethylene has been investigated by a T‐peel test consisting of polyethylene–copolymer–polyethylene. The three ethylene copolymers involved separately vinyl acetate, ethyl acrylate, and acrylic acid. The ethyl acrylate copolymers produce the highest peel strength over the test temperature range of −20 to 50°C, and also yield a high peel strength even at the bonding temperatures of 105–110°C, at which the welding of polyethylene to polyethylene does not occur. The observations of cross sections of the joints with an interference microscope show the presence of an interfacial boundary layer and a mixed layer (of the polyethylene and the copolymer). The relationship between the peel strength and these two layers is discussed. Further, the peel strength‐temperature curves are compared with the tensile properties of t

ISSN:0032-3888    

DOI:10.1002/pen.760160606

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractCharacteristics of several impact test methods in current use are discussed. The construction, operation and performance of an instrumented plate‐projectile (IFF) impact tester is described. Force‐strain curves, energies to any point in the test and failure modes may be inferred from the test data. Also, by inspection of the tested plate, one can see if there are cracks, blanching (development of microvoids) or ductile deformation. This inspection distinguishes between local and catastrophic failure—an important distinction in selection of materials for specific uses. There is reasonable correlation between values from notched Izod and IPP tests, with the latter somewhat more sensitive. Data illustrate the distinction between good and poor fiber‐to‐matrix coupling in reinforced polypropylene. Although there is some sacrifice of impact strength with improved fiber‐matrix coupling, this is more than counteracted by the improvement in static strength and creep resistance. The data show that coupled glass‐reinforced impact grade polypropylene exhibits an interesting balance of static to impa

ISSN:0032-3888    

DOI:10.1002/pen.760160607

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractComparative studies were made on the fabrication characteristics, mechanical properties and thermal stabilities of three commercially available composite systems based on linear monoether polyphenylquinoxaline, P13N polyimide, and Skybond 703 polyimide, reinforced with Modmor II graphite fibers. Fabrication parameters and prepreg conditions were related to the properties of the laminates. Interlaminar shear strength and flexural properties were evaluated before and after the thermal aging at 600°F for periods up to 500 hrs. Thermal degradation of composites at various stages of thermal' aging was studied using optical and scanning electron microscopes

ISSN:0032-3888    

DOI:10.1002/pen.760160608

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe paper describes a computer software package applying a steady‐state hill‐climbing optimization routine to the plastics melt‐extruder screw constrained‐design problem. The purpose primarily is to introduce the optimal screw‐design technique, to show how it is applied to this particular type of problem, to indicate its potential and to encourage its wider use. Screw performance criteria are defined by a theoretical model consisting of the non‐Newtonian isothermal polymer flow equations in terms of the screw‐geometric variables for particular process conditions. The design method is quite general however and a non‐isothermal model may be substituted. Use of the method offers considerable scope and potential for the design engineer to make design processes faster, more positive and logical while reducing the effort required. Interactive use is possible and empirical adjustments can be incorporated with experience. In using the method, the design engineer first specifies the required process conditions of pressure and flow rate at the die and the computer then searches for the set of screw design variables which optimizes the screw power utilization efficiency or any other specified criterion of performance. Such optimal designs are obtained within the set limits of practical constraints on machine dimensions, screw strength and product quality requirements. Some experimental evidence is given relating to the accuracy of the isothermal non‐Newtonian polymer flow model and to its use in the design of small diameter extruder screws. The optimal search technique offers considerable potential as a computer

ISSN:0032-3888    

DOI:10.1002/pen.760160609

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe residence time distribution (RTD) function in a single screw plasticating extruder was theoretically calculated. The calculation is based on the solids conveying, melting, and melt conveying models in extruders. The screw channel is divided into small axial increments and the path of each exiting fluid particle is followed from hopper to die. In addition to the residence times the total shear deformation or strain imposed on the fluid particles was also calculated. This together with the RTD function has led to the definition and calculation of the strain distribution function (SDF). This function is proposed for quantitative characterization of the mixing performance of screw extruders as well as other laminar mixers. Some simple idealized batch and continuous laminar mixers are analyzed in terms of the SDF. Finally, the effect of extruder operating conditions and screw design on the RTD and SDF were investigated by computer simulations.

ISSN:0032-3888    

DOI:10.1002/pen.760160610

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760160601

出版商:Society of Plastics Engineers, Inc.    

年代:1976

数据来源: WILEY