ISSN:0032-3888    

DOI:10.1002/pen.760050209

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractEquations of equilibrium can be used as tools to convert observations of plastic processing operations into a complete process analysis, including the interpretation of simulated fabrication experiments. If material properties of the plastic are known under the fabrication conditions, a predictive process analysis can be made, yielding such data (in the case of extrusion) as membrane thickness and radial velocity. Such predictive analyses also may be used to develop valuable insights into thermoforming operations by means of simulation experiments.

ISSN:0032-3888    

DOI:10.1002/pen.760050202

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractThis article reports the preparation of a number of high molecular weight aromatic amide and imide polymers. An order of relative thermal stability of a series of alternative linkages between benzene rings in aromatic polymers is established on the basis of weight loss of thin films in air. It is found to agree with the stability order established by others by study of model compounds. It is further confirmed by the aging performance of laminates employing such resins. Electrical properties of the polymers were measured as a function of temperature. Change in the dissipation factor with temperature was used to determine Tg, which in turn was correlated to the minimum temperature required to produce laminates. Examples of the performance of these organic polymers in long time exposure tests at elevated temperature are given. Flexural properties of laminates aged and tested at temperatures of 600–650°F are report

ISSN:0032-3888    

DOI:10.1002/pen.760050203

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractFatty acid salts are often added to polymers as processing aids. Although calcium stearate promoted highly reduced mixing torque requirements in polypropylene compositions, this was due largely to lowering of the polymer molecular weight. However, the amount of shear withstood without severe degradation was less. The effects of calcium stearate upon polypropylene stabilization systems were investigated by oxygen absorption studies Up to 50% stabilization was lost, particularly with metals such as copper, with 0.1% calcium stearate even in compositions protected by inhibitors. The stearate evidently reacts with transition metals or their oxides, particularly if acidic materials are present, to give metallic stearates which are extremely effective polyofin oxidation catalysts. Considering these results, the use of stearate processing aids should be avoided if property retention and stability are important in the fabricated article.

ISSN:0032-3888    

DOI:10.1002/pen.760050204

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractFoams are produced by mixing an epoxy resin, a primary polyamine and a trialkoxyboroxine without applied heat. The reaction heat evolved, predominantly from the reaction between the boroxine and the amine, speeds up the gelation of the epoxy resin and simultaneously evaporates methanol, a by‐product, to form the foam, leading to the formation of a highly crosslinked polymer. A theory for the mechanism involves the chemical properties of intermediates, the basicity of the nitrogens, the acidity of the borons, and the mode of curing of the epoxy resin. The physical properties can be varied using different epoxies, amines and boroxines and different proportions. With a typical mixture, the foams produced have densities and thermal conductivities similar to polystyrene foam but have heat resistance up to 300°C. Adhesion to various substrates is excellent. Compression strengths are low but can be increased by the addition of fillers. The foams are self‐extinguishing. Potential applications and method of dispensing the foams are sugge

ISSN:0032-3888    

DOI:10.1002/pen.760050205

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractThe selection of particle size distribution is based on a theoretical concept of the “close packing” of particles. The usefulness of this concept was investigated using silica as the filler in a single epoxy‐hardener system. The viscosity and settling characteristics for several particle‐size distributions and concentrations of silica fillers were studied. These studies show that significant decreases in the viscosities of casting formulations can be obtained using a two‐component filler system which permits the use of higher filler loadigs. The increase in the ratio of coarse filler to fine filler reduced the flexural strength of the castings and increased the rate of settling in the formulations. The effect of parameters other than particle size is demonstrated by the use of non‐sil

ISSN:0032-3888    

DOI:10.1002/pen.760050206

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractH‐Film is a polypyromellitimide which results from polycondensation of pyromellitic dianhydride and an aromatic diamine. Its unique blend of thermal, physical, and electrical properties make it an outstanding candidate for a variety of electrical and non‐electrical end‐use applications. These properties recommend H‐Film for use as Class H (220°C) electrical insulation. Thermal aging of this polymeric film to embrittlement in air will require on the order of ten years at 250°C (482°F), one year at 275°C (527°F), and three months at 300°C (572°F). Even greater thermal durability in inert atmospheres has been observed. Our continuing thermal characterization studies on this polypyromellitimide have resulted in data relating to weight loss and decompos

ISSN:0032-3888    

DOI:10.1002/pen.760050207

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

摘要:

AbstractThis article describes a simple and accurate method for measuring the reactivity and final cure state of epoxy resins. In the method, the reaction of a thin film of epoxy resin between two Nace plates is followed during a complete curing cycle. The method makes it possible to study effect of temperature and catalyst on cure rate, as well as comparing the equivalence of various materials. The techniques discussed in the article may be useful in the application of thermosetting resins other than epoxies.

ISSN:0032-3888    

DOI:10.1002/pen.760050208

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760050201

出版商:Society of Plastics Engineers, Inc.    

年代:1965

数据来源: WILEY