摘要:

AbstractIn the framework of the tetrahedral lattice model of the polymer chain, a precise solution was obtained for the correlation functionG(t) describing the relationships of polarized luminescence (PL) and the nuclear Overhauser effect (NOE) in polymers. The relationships of PL and NOE were compared on the base of precise and approximate (VJGM model) solutions.

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410301

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe crystallization of flexible‐chain polymers capable of forming different polymorphous modifications was considered by using the thermodynamic approach and taking into account kinetic factors. Taking as examples poly(caproamide) and poly(vinylidene fluoride), the changes in free energies in the generation of different crystalline forms were calculated and phase diagrams were plotted in the coordinates degree of coiling of macromolecules and temperature. it was thus possible to establish the thermokinetic conditions for the formation of equilibrium and metastable modifications and the transitions between the

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410302

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractA line profile analysis of the (hk0) reflections of sintered poly(p‐phenylene) is presented. The wide angle X‐ray diffraction maxima were analyzed to study the average size of the coherently diffracting domains as a function of annealing temperatureTA. The results show that the lateral size of the coherently diffracting domains increase first slightly forTA300°C. This is related to a rearrangement of rigid chains from disordered into the crystalline regions. The absence of SAXS supports the view of a nematic frozen‐in liquid crystalline structure contributing to about 40% of the m

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410303

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe glass transition temperatures of styrene copolymers containing different amounts of Zn(II), Co(II) and Ni(II) acrylates were determined by differential scanning calorimetry. Based on these data theTgvalues of the polyacrylates were estimated by the extrapolation method. The observed dependences ofTgon copolymer composition could be described satisfactorily by the Kwei equation. It may be concluded that in all systems ionic crosslinking of similar efficacy occurs.

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410304

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe supermolecular structure of thermoplastic block copolyesters containing different amounts of poly(ethyladipate) has been investigated by small and wide angle X‐ray scattering. It has been shown that the fine structure of the block copolymers depends both on the content of poly(ethyladipate) and heat treatment. The annealed samples and the standard homopolymer have a lamellar structure and the highest crystallinity index. The thickness of the transition layer between the crystalline and amorphous phases increases when the structure becomes less ordere

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410305

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe structural and physical properties of drawn polypropylene‐polycaproamide fibres were investigated. A polycaproamide content up to 7 wt % improves some properties of the fibres. Higher content leads to the formation of porosity, decreases the uniformity of the dispersion of the polycaproamide phase, and deteriorates the mechanical properties. In comparison with polypropylene fibres higher sorption of humidity and lower electrical charge were observed with the polypropylene‐polycaproamide fib

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410306

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe results obtained by testing the PALITequation 100ϱ0[η] + InM=K1M2/3+K2with solutions of some polyphosphates and copolyphosphates have been analyzed and compared with the MARK‐HOUWINKrelationship. The values of the exponentain the MARK‐HOUWINKrelationship were found to be higher for those samples which have higher values ofK1or lower values ofK2in the equation suggested by

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410307

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractA literature review on the preparation of fire retardant polyurethanes based on halogenated compounds is presented. Some properties of the polymers are discussed.

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410308

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractEine Systematisierung der Literaturangaben und experimentellen Ergebnisse zu den Umwandlungen des Vinylchlorids in Gegenwart saurer Agenzien wurde durchgeführt. Je nach den Reaktionsbedingungen erfolgt Komplexbildung (über die CC‐Bindung order mit Beteiligung von Cl), Bildung der 1:1‐Addukte mit Öffnung der CC‐Bindung sowie Zerfall des Vinylchlorids zu HCl und Acetylen. Mit SbCl5erfolgt entweder 1:1‐Komplexbildung oder 1,2‐Chlorierung des Vinylchlorids. Eine kationische Polymerisation des Vinylchlorids wurde nicht oder nur als Nebenp

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410309

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe homopolymerization of vinyl chloride and its copolymerization with ethylene in the presence of catalytic systems composed of transition metal organic compounds such as (C5H5)2TiCl2, vanadium, cobalt, nickel and chromium acetylacetonates, Ti(On‐C4H9)4in combination with Al(C2H5)3, Al(C2H5)2Cl and Al(C2H5)Cl2is studied. The effects of the solvent, e.g. heptane, toluene, benzene, ethyl chloride, and dichloroethane‐1,2, on the process of copolymerization in the presence of the catalytic system Ti(On‐C4H9)4/Al(C2H5)3‐nClnand on the physicochemical properties of the resultant copolymers are

ISSN:0323-7648    

DOI:10.1002/actp.1990.010410310

出版商:Akademie Verlag GmbH    

年代:1990

数据来源: WILEY