摘要:

AbstractThe mechanical response of a smecticAliquid single crystal elastomer (LSCE) to stress applied perpendicular and parallel to the layers is described. We find that the static modulus perpendicular to the layers is two orders of magnitude larger than the modulus parallel to the layer direction, where the latter is completely due to the crosslinking. Macroscopically the width of the smecticALSCE does not shrink when a mechanical stress is applied parallel to the layers while the length of the film increases by a factor of 2 thus demonstrating the in‐plane fluidity of the smectic layerin

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180201

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractStructure changes and charge transfer in the doping process of poly(2,5‐dimethylaniline) (PDMA) were studied by NMR technique. It was shown that not only the polymer chain but also the hydrogen atoms and methyl groups on the aromatic rings were involved in the charge transfer process. A “four ring BQ derivatives” model was proposed to explain the NMR re

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180202

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe evolution of crystallinity and polymorphism during hot‐drawing of amorphous poly(ether ether ketone ketone) (PEEKK) as a function of strain rate, draw ratio, and temperature was investigated. In modification I, the competition of chain extension and molecular alignment is responsible for the strain rate and temperature dependence. Modification II crystallization is basically controlled by chain extension during stretching. The former can be transformed into the latter via relaxation during stretching or annealing at elevated temperatur

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180203

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractWe prepared light emitting diodes with a discotic main chain polymer doped with a tristilbene amine derivative. X‐ray investigations showed the formation of a hexagonal columnar structure in the annealed devices. This increased order leads to a significant reduction of the onset voltage for light emission down to 4 · 105V/

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180204

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractFive kinds of poly(aryl ether ketone)s (PAEKs) having para‐substituted linear molecular chains were synthesized via nucleophilic substitution reaction of the corresponding difluoro‐ and dihydroxy‐compounds. The glass transition temperature and melting temperature of the PAEKs measured through differential scanning calorimetry in addition to those of other PAEKs reported are approximately proportional to the logarithm of the ratio of the mole fractions of ketone and ether groups in the repeating unit of the PEAKs. On the other hand, this ratio does not affect the crystal structure of the

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180205

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractTime‐dependent phase separation/transition was observed in aqueous solutions of poly(N‐isopropylmethacrylamide) in the temperature range 38–42°C. The time before the second phase appears is a function of temperature and may reach up to several

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180206

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractAddition of LiCl to ethereal solutions of polystyryllithium retards propagation of the polymerization at low polymer concentration, but accelerates it at higher polymer concentrations. This phenomenon is accounted for by the dual action of LiCl. Its dissociation yielding free common Li+ions which diminish the concentration of the reactive free polystyryl anions dominates at low electrolyte concentrations. However, at their higher concentrations the Li+scavenging action of LiCl, resulting in the formation of LiClLi+triple ions, becomes important, it reduces the concentration of the free Li+ions and increases, therefore, the proportion of the reactive free polystyryl anions.

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180207

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractKinetic and polymer analytical results obtained with the systems Me2Si(Ind)2ZrMe2/[B(C6F4Si(i‐Pr)3)4]−[(C6H5)3C]+(2)and Me2Si(Ind)2ZrMe2/[B(C6F5)4]−[(C6H5)3C]+(3)in olefin polymerizations are compared (Me: methyl; Ind: indenyl). Both systems show that the polymerization rate increases with increasing metallocene concentration in a surplus due to the formation of binuclear species. The expected influence of increasing cation‐anion distance on the stereo‐errors of the poly(propylene)s when changing from system3into system2could not be

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180208

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

Abstractpoly[isobutene‐co‐(p,m‐chloromethylstyrene)]‐graft‐poly(2‐methyl‐2‐oxazoline) graft copolymers (GP) were prepared by the “grafting from” method throught the cationic polymerization of 2‐methyl‐2‐oxazoline (MeOXA) initiated by a statistical copolymer is isobutene and chloromethylstyrene. The unusual viscosity behavior in chloroform solution of these polymers, the dynamic laser light scattering analysis in aqueous solution, as well as the solubility in polar solvents like water and methanol demonstrate the amphiphilic character of the graft copolymers and indicate the formation

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180209

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractHorseradish peroxidase catalyzed polymerization of 8‐hydroxyquinoline‐5‐sulfonate (HQS) has been studied byin‐situNMR spectroscopy. The 2, 4 and 7 positions of the HQS are involved in oxidative free radical coupling with other HQS molecules with the order of reactivity being 7 ≥ 2>4. A mechanism for the oxidative free radical coupling and structure of the resulting polymer is proposed, which is supported by13C NMR spe

ISSN:1022-1336    

DOI:10.1002/marc.1997.030180210

出版商:Hüthig&Wepf Verlag    

年代:1997

数据来源: WILEY