摘要:

Plastics may be subjected to mild stress and strain without failure or they may be subjected to weak solvents or aqueous surfactants without failure, but when they are subjected to combination of these two types of variables they often suffer catastrophic brittle fracture. Such failure has been named environmental stress-cracking (ESC). Environmental stress-crack resistance (ESCR) is generally directly related to molecular weight, narrow molecular weight distribution, and low crystallinity. Frozen-in stresses from processing aggravate ESC and are relieved by annealing, but further annealing also promotes crystallization which aggravates ESC. Polyaxial stress is often mentioned as an essential factor in ESC, and strain-induced orientation may be important in the mechanism of cracking.

ISSN:0360-2559    

DOI:10.1080/03602558108067703

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Because of their good mechanical and processing properties as well as their low price, polymers have replaced such traditional materials as metal and wood in many fields of application. However, they lack one important characteristic-they do not conduct electricity. As with practically all organic substances known to date, they are usually good insulators; only a few categories can be classified as semiconductors. Materials which display higher conductivity can be obtained by synthesizing different polymers with a conjugated or aromatic backbone chain [1], but such materials, although classified as macromolecular, do not show the properties that would make polymers attractive from the point of view of application. Being poorly soluble, brittle, and melting at high temperatures, usually with decomposition, they are interesting practically only from the theoretical point of view.

ISSN:0360-2559    

DOI:10.1080/03602558108067704

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The occurrence of weld lines throughout the field of polymer processing has been recognized as one of that discipline's unsolved problems [1]. A recent review has been made of this phenomenon which occurs wherever molten polymer flow fronts meet [2]. The mechanical properties of weld regions have been determined to be very sensitive to processing conditions in both amorphous and semicrystalline injection-molded thermoplastics [3–8].

ISSN:0360-2559    

DOI:10.1080/03602558108067705

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Only a few short years ago, plastics were best known for their insulating properties and great strides were made in electronics, in electrical equipment, and in electrical component design as the dielectric strength of plastics was improved. The whole field of thermal insulation was advanced as ways were found to generate better plastic fibers and foams which could give an order of magnitude better insulation than ever before. And yet, today many of us are spending our time looking for ways to make plastics into better conductors-better conductors of electrons and better conductors of heat. Our reasons are as varied as the many fields from which we come, but they are all related to the fact that plastics have many other very valuable properties aside from their insulating abilities. To make full use of these in many applications, plastics should be electrically and/or thermally conducting.

ISSN:0360-2559    

DOI:10.1080/03602558108067706

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

S-846, a saturated polyester solution, is finding use as a building block to customize SMC/BMC/Match Die Molding formulations. The high solids content (80% in styrene) permits effective shrink and low profile control while simultaneously maintaining low paste viscosity at minimum styrene levels. S-846 is used in conjunction with a second thermoplastic, and the many combinations of materials possible provide the compound designer with a totally new set of limits including excellent pigmentability with low shrink, improved water resistance, higher filler loadings, and lower compound costs.

ISSN:0360-2559    

DOI:10.1080/03602558108067707

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0360-2559    

DOI:10.1080/03602558108067702

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor