摘要:

Aromatic, fully conjugated polymers are a class of polymers attracting significant interest in academics as well as industry. In particular, poly-(p-phenylene) (PPP) and poly(p-phenyienevinylene) (PPV) are important materials due to their thermal stability and electrical conductivity after doping. Very recently their application as organic light emitting layers in polymeric LEDs has stimulated extensive research activity in this field of conjugated polymers.

ISSN:1532-1797    

DOI:10.1080/15321799608014857

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Photochemistry is concerned with chemical changes that may be brought about by the absorption of light [1]. In principle, the photochemical reac-tion of a substance proceeds according to two laws. The first one was proposed by Grotthus and Draper in 1818 and states that “a chemical reac-tion of a certain substance only takes place via the excitation of the mole-cule by the absorption of light quantum of sufficient energy.” The second law is the photochemical equivalent law proposed by Einstein in 1912 which states that “each photon or quantum absorbed activates only one molecule” [2].

ISSN:1532-1797    

DOI:10.1080/15321799608014858

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Cellulose, either as a major component in wood or as the prime textile fiber cotton, is most frequently implicated in fire, causing injuries and fatalities [1]. When ignited, cellulose undergoes thermal degradation, form-ing combustible volatile compounds which become involved in the propaga-tion of fire. Fortunately cellulose has a chemical composition which makes it easily amenable to interactive flame-retardant treatments. Because flam-mability is a relative rather than an absolute concept, there are no truly flame-retardant fabrics, and the best that can be attained is some given level of flame resistance. Barker and Drews [2] proposed that with cellulose, the problem of fire can be described as two distinct phenomena, glowing and flaming, which present different potential hazards and should be ap-proached in different ways. Glowing is a direct oxidation of solid cellulose or its degradation products. It is generally a slow combustion and is of great concern for only specific items, such as carpets, upholstery, mattresses, and insulation. Flaming combustion, on the other hand, is a complex process involving both solid and gas phases, and may be modeled as a cyclic pro-cess. In the initial stages of burning, heat is supplied to cellulose, initiating endothermic degradation reactions in which large polymer molecules are broken into smaller, volatile fuel compounds. The pyrolysis products dif-fuse to the surface and mix with oxygen from the air so that combustion may take place. This combustion is exothermic, and the heat thus liberated is partially transferred back to fiber surfaces to continue polymer pyrolysis, maintaining a continuous supply of gaseous fuel for further propagation. This process is shown schematically in Fig. 1 [3, 4]. Early attempts to explain the mechanism of flame-retardant action of

ISSN:1532-1797    

DOI:10.1080/15321799608014859

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Organic thin films have received a great deal of interest due to their extensive applications in the fields of mechanics, electronics, and optics [1-6]. Applications include chemical, physical, and biological sensors, micro-electronic devices, nonlinear optical (NLO) device, and molecular devices [2]. In spite of a large number of studies in this area, in only a few cases have these materials been successfully used for electronically and optically based applications. This is mainly because organic films often show poor thermal and chemical stabilities and poor mechanical toughness [2, 5]. Therefore, it is of interest to develop polymer thin films of high quality for a variety of industrial applications.

ISSN:1532-1797    

DOI:10.1080/15321799608014860

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:1532-1797    

DOI:10.1080/15321799608014861

出版商:Taylor & Francis Group    

年代:1996

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:10.1080/15321799608014856

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor