摘要:

The principles of the use of sterically hindered amines as polymer and monomer stabilizers have been established by M. V. Neimanet alThey studied the chemistry of a new class of compounds, the nitroxyl radicals [1-3]. The possibility of the use of these radicals as stabilizers is based on their recombination reaction with active radicals. Nevertheless, for many reasons, nitroxyl radicals have not been widely used as thermo- and photo-stabilizers. In the course of studies on stabilization by these compounds it has been unexpectedly observed that sterically hindered amines–precursors of nitroxyl radicals–are excellent stabilizers against photodegradation and that their efficiency in this field is much better than that of most of known stabilizers. During the recent years a large number of papers have been dedicated to the synthesis, the application, and the action mechanism of stabilizers. This paper is an attempt to generalize the data in this field.

ISSN:1532-1797    

DOI:10.1080/07366578208081062

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Over the past five decades the analytical ultracentrifuge has been a versatile tool in the study of macromolecules and colloidal particles. Several textbooks [1–4] and review articles [5–10] deal with experimental techniques and theories for complete characterization of macromolecular species. However, the first published articles on the analytical ultracentrifuge dealt with the analysis of particle size distributions in suspensions of inorganic colloids. The emphasis has now shifted to organic polymers following the discovery that a large number of such polymers exist in nature. Before the development of the ultracentrifuge, the existence of such giant molecules was not recognized; the molecular kinetic units of proteins and of high organic polymers in solution were simply thought of as clusters of much smaller molecules, forming particles of undefined mass. Beginning with the elegant investigations of Svedberg [11, 12] on ultracentrifugation, such substances were revealed to be macromolecules, large because they contain a huge number of atoms connected together by primary chemical bonds [13]. Following a long and fruitful series of investigations in the early twenties and thirties, Svedberg wrote in one of his articles [12], “the proteins are built up of particles possessing the hallmark of individuality and therefore are in reality giant molecules. We have reason to believe that the particles in the protein solutions and the protein crystals are built up according to a plan which makes every atom in them indispensable for the completion of the structure.” Almost at the same time, it was Staudinger [14] who clearly demonstrated that substances such as polystyrene and natural rubber exist in solution without change in molecular weight regardless of the solvent employed .

ISSN:1532-1797    

DOI:10.1080/07366578208081063

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

At different times in the history of polymer science specific subjects have come to center stage; for intense investigation because they represent new and important intellectual challenges as well as technological opportunities. In past years the chief incentive for the scientific study of biodegradation of polymers was concern with the problem of preventing or retarding attack on such products by microorganisms, insects, rodents, and other animals. Many research efforts in synthetic polymer chemistry were directed toward the synthesis of polymers resistant to biodegradation. The paramount feature sought by polymer chemists and engineers was stability, and the production of such materials has been very impressive. This is still a very important factor in many applications such as paints, protective coatings, textiles, electrical insulation, and plastic films and sheets used for many applications such as upholstery and floor covering. Fortunately, most synthetic polymers are resistant to biological attack and many of these studies were concerned with choosing additives which would be bioresistant, or with providing protection for the susceptible ingredients in the plastic formulation by the use of fungicides and other biocides. In recent years, however, the picture has changed and there has been a raft of publicity about degradable plastics [1–10].

ISSN:1532-1797    

DOI:10.1080/07366578208081064

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

In 1962 Kimura, Takitani, and Imoto [1] found that an aqueous solution of starch could easily polymerize methyl methacrylate (MMA), and about one-half of the polymerized MMA was grafted on to starch. This novel polymerization was called “uncatalyzed polymerization.” Since then, a large number of macromolecules other than starch have been studied, and many of them are effective for initiating the radical polymerization of MMA.

ISSN:1532-1797    

DOI:10.1080/07366578208081065

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Graft copolymerization onto textile fibers is a challenging field of research with unlimited future prospects [1–6]. This is attractive to chemists as a means of chemical modification of natural macromolecules since, in general, degradation could be minimized. Thus it is hoped to retain the desirable properties of the natural material and give it additional properties through the added polymer. Means of forming copolymers with natural macromolecules are now well understood because the techniques of polymer chemists are usually applicable. A vast number of combinations of composition and conformation is possible for each copolymer, and the properties of each copolymer may vary with the mode of formation employed.

ISSN:1532-1797    

DOI:10.1080/07366578208081066

出版商:Taylor & Francis Group    

年代:1982

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:10.1080/07366578208081061

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor