ISSN:0032-3888    

DOI:10.1002/pen.760040202

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760040203

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractPrevious work has demonstrated the possibility of obtaining curves of normal stress as a function of shearing stress for polymer solutions through the measurement of the swelling of a jet of the solution extruded from a long capillary. A new formulation of reduced variables is offered which allows results obtained at different concentrations to be correlated by a single curve for a given polymer system. Results are presented for water solutions of carboxymethylcellulose, and for xylene solutions of polyisobutylene. For polyisobutylene, the correlation is similar to those obtained by other investigators who measured normal stresses by standard techniques.

ISSN:0032-3888    

DOI:10.1002/pen.760040204

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractThe paper presents the “Thermophysical Profiles” of selected plastics and discusses their significance in correlating the mechanical properties with the molecular and crystalline structure of these polymers. The profiles were obtained with a new instrument, by imposing a fixed, forced elastic vibration on the speciments' surface and by recording continuously the energy absorbed by the specimens through a temperature range from −200°F to +500°F The profiles locate the first and second order transition points of the test materials (defining, thus, the temperature limits of their use) and indicate the change in modulus with temperature in the viscoelastic region of the polymers. Profiles of the following materials are discussed, low and high density polyethylene, polypropylene and PVC films and unfilled samples of cast epoxy and polyester

ISSN:0032-3888    

DOI:10.1002/pen.760040205

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractAttempts are made, in the light of published information, to decide the factors affecting network structure in commercial polyester resins and the effect of network variations on physical properties of polyfumarate‐styrene copolymers. An approach towards the optimum in chemical and heat resistant polyester laminates is suggested by examination of the influence of polyester chain structural variations on these propertie

ISSN:0032-3888    

DOI:10.1002/pen.760040206

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractRecent dielectric measurements at 60 cycles per second have shown a good correlation amond α‐peak, Vicat and dilatometric Tgtemperatures. Other measurements of copolymer systems have suggested a re‐examination of existing second‐order transition temperature relationships. This study has revealed that the most common of these equations are mathematically equivalent and not fully satisfactory for explaining all observations. A relationship is proposed which is capable of fitting either linear or non‐linear second‐order transition data for compatible copolym

ISSN:0032-3888    

DOI:10.1002/pen.760040207

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractThe basic requirements for optimization of filament‐wound pressure vessels are a high strength‐to‐density ratio of the fiberglass‐resin composite and an arrangement of the glass fibers in such fashion that each fiber carries, at a given pressure, the same constant load throughout the cylindrical portion as well as the end closures. The basic relations governing the isotensoidal design are derived, and the ideal shape of the end closure is defined. The relative merits of geodesic and “in‐plane” wrapping are discussed. Structrual efficiencies accomplished in several practical applications

ISSN:0032-3888    

DOI:10.1002/pen.760040208

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractStudies of capillary extrusion measurements using an Instron rheometer show that certain types of high density polyethylene exhibit a discontinuity in the shear stress/shear rate curve. This behavior which is separate and distinct from the phenomenon of melt fracture is caused by a change in the flow regime. It is manifested by oscillation of the recorded load while the rheometer piston is operated at a constant rate. Therefore, this behavior has been termed “oscillating shear phenomenon”. The location and magnitude of the fluctuations are functions of the molecular parameters of the polymer as well as the melt temperature, capillary geometry, and other rheometer variables. Evidence is presented which indicates that the change in flow regime could result from the orientation of the melt as it enters the capill

ISSN:0032-3888    

DOI:10.1002/pen.760040209

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractSolution‐grown crystals of polyethylene may reach lateral dimensions large enough for optical microscopy. Interference microscopy represents, in this case, a suitable method of observation of morphology and defects as well as quantitative determinations. The double‐beam interference method used in the Baker type microscope has been applied to determine refractive indices and lamellar thicknesses. The Nomarski double‐beam interferometer has been used for hot‐stage experiments. Multiple‐beam techniques involving silvering of crystal surfaces and using an ordinary light microscope for observation have been developed. The applicability of the different types of interference microscopy to polymer research is illustrated in a series of representative photomicrographs of pol

ISSN:0032-3888    

DOI:10.1002/pen.760040210

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractCarefully controlled experimental techniques were used to study the effect of variations in bulk E glass surfaces on bound life and wetting. Bond life (stability of the bound in the presence of moisture) was determined visually as the time required for hot water to remove an epoxy resin coating from the glass surface. Wetting was determined by the captive bubble technique. Both properties were significantly affected by variations of the glass surface. The bound life studies emphasized the importance of the coupling agent in promoting bound stability in a hot water environment. The only example of the glass surface not treated with a coupling agent that had a satisfactory bound life was the alkali‐deficient glass surface prepared by acid leaching. The surprisingly poor bound lives of the degassed and freshly cleaved (high energy) glass surfaces indicated that the wet strength retention of laminates would be poor when prepared by instantaneously applying epoxy resin without a coupling agent to the glass fibers directly as the fibers are formed. Cleanliness and surface and surface roughness were the only two variables found that promoted wetting. This discrepancy with respect to cleanliness indicated that wetting was not the controlling factor for bond lif

ISSN:0032-3888    

DOI:10.1002/pen.760040211

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY