摘要:

To meet the stringent demands placed on lubricants by the progress of modern technology, it has become necessary to supplement conventional mineral oils and greases. New kinds of lubricants are also needed where products of petroleum crudes cannot even be considered. For example, new and special types of lubricants are required in environments subjected to extreme temperatures, high vacuum, nuclear radiation, and chemically oxidizing or reducing effects. The attention of scientists is therefore being focused on the development of synthetic lubricants for more demanding physical, chemical, and thermal requirements.

ISSN:1532-1797    

DOI:10.1080/07366578908055162

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Over the past two decades, ylide polymer chemistry has been an area of great interest to chemists due to its theoretical implications and industrial significance.

ISSN:1532-1797    

DOI:10.1080/07366578908055163

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Polyethylene terephthalate (PET) is one of the fastest growing thermoplastic polyesters used extensively for fibers, films, bottles, injection molded parts, and other products.

ISSN:1532-1797    

DOI:10.1080/07366578908055164

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Among the various high temperature polymers, those based on aromatic units, such as poly(2, 6-dimethylphenylene oxide) (PPO), poly(pheny1ene sulfide) (PPS), poly(ether ether ketone) (PEEK), and poly(ether sulfone) (PES), have attracted much attention in the last few years due to their good thermal and chemical resistance. One of these polymers, PPS, is also an important high strength/high temperature engineering thermoplastic that is finding increasing use in technological applications such as molding resins, fibers, and matrices for thermoplastic composites. PPS consists of para-phenylene units alternating with sulfide linkages. The first known report of its synthesis was by Grenvesse in 1898 [1]. However, interest in the synthesis of PPS only began in 1948 when Macallum 121 described the preparation of phenylene sulfide polymers by the melt reaction of p-dichlorobenzene with sodium carbonate and sulfur. Further investigation on the synthesis of PPS by Lenz and coworkers [3–5], and later by Edmonds and Hill [6], developed PPS into a commercial reality. After synthesis, the polymer is an off-white powder that has a glass transition tem- perature (T) at 85°C and melting point at about 285°C. The B 3+ off-white coloration is known to be due to the presence of Fe ions in the forms of FeCl that arise from the steel reactor 3 utilized to synthesize PPS. However, this problem can be avoided by utilizing a titanium reactor. Therefore, “white” or purer polymer can be obtained [7]. The study of the structure and molecular weight distribution of PSS has been precluded by its intrinsic high chemical resistance. Only recently, a gel permeation chromatographic system (GPC) capable of determining molecular weights and molecular weight distribution of PPS has been developed [8]. The GPC exyeriments are conducted utilizing a-chloronaphthalene as the solvent at 21°C in order to maintain PPS in solution. Typical polydispersity ratios of PPS synthesized by the method of Edmonds and Hill are in the order of 1.5–2.0.

ISSN:1532-1797    

DOI:10.1080/07366578908055165

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

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

ISSN:1532-1797    

DOI:10.1080/07366578908055161

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor