摘要:

The problem of synthesizing macromolecules of accurately predetermined structure is an intriguing one; not only does such a synthesis provide a challenge to our chemical ingenuity but it also offers the possibility of providing a new range of materials with potentially valuable properties. To achieve a synthesis of this kind, the random features associated with conventional polymerization and copolymerization must be eliminated. Apart from gross structure defects such as chain branching and wrong-way addition, randomness in addition polymerization arises because the nature of the reaction between the propagating chain and the monomer is not uniquely defined. Thus, in homopolym-erization, addition may lead to either iso or syndiotactic placement, while in copolymerization further ambiguity is introduced by the possibility of reaction between a given propagating chain and any monomer species present; similar remarks also apply to conventional condensation copolymerization.

ISSN:1532-1797    

DOI:10.1080/07366578708081914

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Among the vinyl monomers, acrylonitrile is the only monomer used for the production of synthetic fibers. Other vinyl monomers lack cohesive forces between the molecular chains of their polymers and, hence, can not compete with acrylonitrile [1]. Acrylic fiber has replaced wool in many major applications, particularly in hand knitting and hosiery garments. The majority of knitting yarns are usually bulky yarns which go into the manufacture of pullovers, sweaters, socks, etc. Acrylic fiber has been able to replace wool considerably in these applications. Blankets and carpets are other applications where acrylic fiber competes with wool [2] because of its high elasticity, color brilliancy, volumenosity, easy shampooing, resistance to pilling, good light and colorfastness values, etc.

ISSN:1532-1797    

DOI:10.1080/07366578708081915

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this review we are primarily concerned with the use of apparent molal volume and apparent molal compressibility of polyelectrolytes along with their corresponding monomers in elucidating the ion-ion and ion-solvent interactions in aqueous and nonaqueous solutions. Though the main emphasis will be given to synthetic polyelectrolytes, the biochemical significant (natural) ones are not excluded altogether. It is hoped that this information will provide researchers with up-to-date knowledge of the subject matter and give a new impetus to further study on the subject. Most of the works on molal volumes and ultrasonic velocity measurements were confined up to the middle sixties to solutions of simple electrolytes. These works gave valuable information about the structure of solutions as well as about the fundamental properties of solutions.

ISSN:1532-1797    

DOI:10.1080/07366578708081916

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Water-soluble nonionic polymers occupy a special place among synthetic polymeric materials. Most of them possess a number of unique properties allowing various industrial and medicinal applications. Such important industrial branches as coal mining, oil recovery, production of textiles, paper, lacquers, adhesives, cosmetics, and medicinal preparations cannot be conceived without these polymers. For instance, poly(acrylamide) and poly-(oxyethylene) can decrease pressure losses, increase considerably the drilling time, reduce the time of flooding underground spaces, and increase the speed of ship movement and pumping of liquids. Very important is the role of water-soluble nonionic polymers in the textile industry where they have successfully replaced expensive natural materials in the processes of cloth sizing and finishing and are used in the production of new kinds of fabrics possessing high mechanochemical characteristics. The use of these polymers is also important in medicine due to their good compatibility with water, high tendency to complex, and lack of toxicity.

ISSN:1532-1797    

DOI:10.1080/07366578708081917

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

More than two decades ago, Bonner reported the first preparation of poly (aromatic ketones) (PAK) by aluminum chloride-catalyzed acylation of diphenyl ether with aromatic diacid chlorides [1]. These were low molecular weight materials because of solubility limitations. In the intervening years, significant progress has been made in synthetic methodology, and now a large variety of structures is available for study. Unlike poly-Caryl sulfones) which are typically amorphous, most PAK's exhibit partial crystallinity, usually with melting points above 300°C. Like the sulfones, the ketone polymers possess high thermal stability and exhibit excellent electrical and mechanical properties. The development of this interesting polymer family is the subject of this review.

ISSN:1532-1797    

DOI:10.1080/07366578708081918

出版商:Taylor & Francis Group    

年代:1987

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:10.1080/07366578708081913

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor