摘要:

AbstractPeroxidase‐catalyzed phenol polymerization in the presence of hydrogen peroxide has been extensively studied. The process offers many advantages over the conventional chemical process to produce phenol‐based resins. The enzymatic process avoids the use of formaldehyde and results in minimal formation of by‐products due to high specificity of the enzyme toward the reactants. A number of phenolic derivatives and aromatic amines can be polymerized in different reaction systems, such as bulk solvents, reversed micelles and Langmuir trough. The polymers produced produced exhibit morphology reflective of the templating effect of the medium used to prepare the materials. Polymer molecular weight and polydispersity can be controlled by suitable design of the reaction medium. Polymer characteristics such as structure, thermal and temporal stability, functionalization and processability are reviewed. Conductivity, nonlinear optical and related functional properties are discussed with regard to potential applica

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470501

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractIsopropylidene‐3,4,4‐trimethyl‐oxazolidine3is an initiator for the radically and anionically induced polymerization ofN‐ethylmaleimide (NEMI) (Scheme 2). An electron transfer from the CT‐complex of NEMI/3leads to the radical anion/radical cation pair. In THF (ϵ=7.58) diradicals result from these processes, connected with a radical homopolymerization of NEMI (experimentA). The polymerization is inhibited by TEMPO and not by H+‐ions (experimentsBandG). In NEMI as “solvent” (experimentE), which possesses a high dielectric constant, we postulate an anionic mechanism for the NEMI homopolymerization. The polymerization also takes place in the presence of TEMPO and it is inhibited by H+‐ions

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470502

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractModel calculations on low molecular weight polybutadienes (PCILO, MM2) lead to statements about preferred conformations and, therefore, about the secondary structure of these polymers. The results of the calculations enable a better interpretation of experimental results obtained in epoxidation reactions of the polybutadienes.

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470503

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470504

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe synthesis and properties of simultaneously interpenetrating networks (SINs) based on poly(polyethylene glycol diacrylate) (PEGDA) and epoxy (diglycidyl ether of bisphenol A, DGEBA) were studied. The effect of compositional variation on the morphology and properties of products was investigated. The swelling coefficient, densities, glass transition behavior, and thermal stability of these interpenetrating networks (IPNs) are discussed. Microphase separation morphological structures were found in all PEGDA/DGEBA IPNs. Decreased swelling ratios compared to the calculated swelling coefficients based on the weight additivity of the components were obtained after the formation of IPNs. Increased density and thermal stability were also obtained in these IPNs, implying the existence of interpenetration (topological entanglements) among the component networks.

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470505

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractSystematic synthesis of interpenetrating polymer networks (IPN) from poly(chromium acrylate) (PCrA) and zinc acrylate (ZnA) using divinyl benzene (DVB) as crosslinker has been carried out. Swelling studies and scanning electron microscopy (SEM) were performed to examine the extent of crosslinking and phase behavior of the IPN. The crosslinking decreases with the increase of linear polymer concentration and its molecular weight, respectively. On the other hand, it increases with the increase of concentration of crosslinking agent and monomer II, respectively. The IPN was found to be thermally stable up to 300 °C

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470506

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractPrevious calculations have suggested that the formation and the stability of charge transfer bonds in doped polyconjugated systems may be maximized by a favored topology of the dopant molecule. The preferred site of attack is found where the steric hindrance is minimized. Following these principles, regiospecific poly(3,3″‐dihexyl‐2,2′:5′,2″‐terthiophene) was synthesized and doped with FeCl3. The time and temperature dependence of the dedoping process has been studied by the analysis of the doping induced infrared spectrum. This material in the doped state shows an extremely great stability (in air, even at relatively high temperatures) never previously reported for any other

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470507

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe surface enrichment in thin bilayer films of poly(vinyl chloride) (PVC) and deuterated poly(methyl methacrylate) (PMMAd) was studied by neutron reflectometry, X‐ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS). In a layer system, where the PVC film is placed on top of a thin PMMA film, the PMMA chains migrate to the surface, although annealing of the films is performed below the glass transition temperature of PMMA. In addition, the surface segregation in blends of these materials was studied by XPS and SSIMS. In all cases PMMA is enriched at the surface. Results from the different techniques, probing different, sample depths, are consistent, if an exponential concentration profile of PMMAd at the surface is assumed. Concentration profiles at the surface are discussed with respect to theoretical models and diffusion coefficients are estimate

ISSN:0323-7648    

DOI:10.1002/actp.1996.010470508

出版商:Akademie Verlag GmbH    

年代:1996

数据来源: WILEY