摘要:

AbstractA series of PPV copolymers containing 2‐nitro‐1,4‐phenylenevinylene (NO2‐PV) units were prepared via the water‐soluble precursor route. They were obtained in film form and were doped with I2and FeCl3. Doping increased the electrical conductivities to maximum values of about 3×10−2and 3×10−1s cm−1, respectively, for the two dopants. Conductivity depended strongly on the composition of the copolymers; it reached a maximum value at ca. 1–2 mol % of NO2‐PV units in the copolymers and then dropped rapidly with further increase in NO2‐PV content. Electronic effects of the substituent and morphological changes induced by copolymerization appear to interplay intricately, resulting in the occurrence of a maximum conducting composition. © 1

ISSN:0887-6266    

DOI:10.1002/polb.1993.090310111

出版商:John Wiley&Sons, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractExtended‐chain crystals of polyethylene grown at elevated pressure and temperature were analyzed for the first time by atomic force microscopy. It was possible to compare the typical fracture surface striation features with those obtained earlier by electron microscopy. High resolution atomic force microscopy on flat surfaces enabled the recording of an atomic scale regularity that could not be fully indentified. © 1993 John Wiley&Sons, I

ISSN:0887-6266    

DOI:10.1002/polb.1993.090310112

出版商:John Wiley&Sons, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractStructures of semi crystalline high‐molecular weight polyethylene and their changes with temperature were studied by analysis of Raman spectra. Decomposition of spectra into contributions of an orthorhombic crystalline phase, a meltlike phase, and two kinds of transition regions yields the respective mass fractions. The results of temperature dependent measurements is indicative of a largely reversible surface melting process, the transition regions being located at the crystal surfaces. As‐polymerized samples show a large fraction of the intermediate phase. Annealing leads to a reduction of this phase. © 1993 John Wiley&Sons,

ISSN:0887-6266    

DOI:10.1002/polb.1993.090310113

出版商:John Wiley&Sons, Inc.    

年代:1993

数据来源: WILEY

ISSN:0887-6266    

DOI:10.1002/polb.1993.090310114

出版商:John Wiley&Sons, Inc.    

年代:1993

数据来源: WILEY

ISSN:0887-6266    

DOI:10.1002/polb.1993.090310115

出版商:John Wiley&Sons, Inc.    

年代:1993

数据来源: WILEY