摘要:

AbstractMicelles of a block copoymer poly(styrene/butadiene/styrene) with cores consisting of polybutadiene blocks were stabilized in dilute solutions by UV radiation in the presence of a photo‐initiator and also by fast electrons, and micelles of a block copolymer poly(styrene/ethene‐co‐1‐butene/styrene) with cores formed by the aliphatic blocks were stabilized by fast electrons, in dilute solutions. Stabilization of micelles, i. e., crosslinking of the chains in micellar cores as well as the properties of stabilized micelles were studied by conventional light scattering, by light scattering photon correlation spectroscopy and by gel permeation chromat

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830211

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe polymorphic behaviour of polymers\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \rlap{--} (OOC} - {\rm (CH}_{\rm 2} {\rm )}_{{\rm n - 2}} - {\rm COO} - {\rm C}_{\rm 6} {\rm H}_{\rm 4} - {\rm C(CH}_{\rm 3} {\rm ) = CH} - {\rm C}_{\rm 6} {\rm H}_{\rm 4} {\rm \rlap{--} )}_{\rm X} $\end{document}(n = 8, 10) has been investigated. They show thermotropic, mesophasic properties with a nematic structure. Both polymers exhibit a multiple solid state polymorphism which is a function of the temperature and of their thermal history.

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830212

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractAs a part of studies on wholly aromatic polyamides containing bridged biphenylylene groups, poly(3,8‐phenanthridinonediyl terephthalamide) (DAP‐T) was prepared from 3,8‐diaminophenanthridinone and terephthaloyl chloride. The solutions of DAP‐T samples in high concentration sulfuric acid exhibited optically different phases, depending on temperature and concentration, like those of poly(1,4‐phenylene terephthalamide) (PPD‐T). The phase diagram of the DAP‐T‐99,0% H2SO4system was established and compared with that of the PPD‐T‐99,0% H2SO4system. Both were essentially similar. The flow of high concentration dopes of DAP‐T and PPD‐T through spinneret holes showed non‐Newtonian characteristics. The liquid‐crystalline solutions of DAP‐T in 99,0% sulfuric acid were spun into fibers using water as a coagulant. The tensile strength and initial modulus increased with increasing degree of stretching between spinneret and collection roller. The annealing of fibers caused an increase in tenacity and modulus, and a tensile strength of 25 g/den and an initial modulus of 1 000 g/den could be reached. Both spun fibers and annealed fibers showed x‐ray diffraction patterns displaying distinct layer line streaks, from which the fiber period was estimated to be 17,2 Å. This agreed with the repeat distance in the direction of molecular axis calculated on the basis of extend

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830213

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA number of wholly aromatic copolyamides containing bridged biphenylylene groups were synthesized from a mixture of aromatic diamines and terephthaloyl chloride, on one hand, and from a mixture of aromatic diacid dichlorides and 1,4‐phenylenediamine, on the other hand. Each mixture of diamines and of diacid dichlorides was constituted of a phenylene derivative and a bridged biphenylylene derivative. The copolyamides synthesized were dissolved in high concentration sulfuric acid and spun into fibers. The fibers spun showed fairly high tensile strengths and high initial moduli, but annealing caused further increase in strength and modulus. All the copolyamides studied had very high thermal resistance

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830214

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA new method for the determination of the cmc using a dialysis technique which allows monomeric species to diffuse through but not micelles has been applied for determining the mixed micelle composition. The method is based on determining the amount of surfactant that diffuses through at two different times which allows for the calculation of the cmc by use of the appropriate equation. This method requires the preparation of only one concentration of solution and lends itself particularly well to the determination of the composition of mixed micelles.

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830215

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractPractical hints for the application of the indirect Fourier transformation method are given. In detail there are discussed the problems of stabilization of the least squares routine, the estimation of the maximum dimension of the particles, the choice of an appropriate number of the spline functions, the combination of scattering functions measured with different primary beam geometry, standard deviation and error propagation of the solution functions, influence of the interparticle interference effect and background scattering on the results, determination of the radius of gyration and the scattering intensity at zero angle and finally the possibility of simulation of measuring curves starting with model bodies is described. It is attempted to demonstrate the advantages of indirect Fourier transformation on hand of several practical examples.

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830216

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractSystematic studies were performed on interpolymer complex formation between Poly(acrylic acid) (PAA) and poly(ethylene oxide) (PEO) in THF‐water mixtures of different compositions. Viscosity behaviour during complex formation in mixed solvents was found to be entirely different from that observed by other workers in aqueous and in pure organic solvents. The result are interpreted in terms of, (a) preferential solvation of the polymer, (b) Probable change in conformation of the polyelectrolyte moleculer. (c) association of complex molecules in a medium of low dielectric constant, and (d) expected disordering of bound water molecules around PEO by THF. Irrespective of solvent composition, interpolymer complex of PAA and PEO was always found to have 1:1 unit mole rati

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830217

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA modified method for the determination of the number of isotactic sitesC* and the overall propagation rate constantk̄pof propene polymerization catalysts with14C‐labelled carbon oxides is proposed: an excess of14CO2or14CO is added in the abscence of propene and alkylaluminium to a non‐deactivated polymer sample drawn from the polymerization slurry.The specific radioactivity of the polymer as a function of the time of contact with the radio‐actively labelled inhibitor sharply increases within short times of contact (14CO2≤ 20 min,14CO ≤ 5 min). This is followed by a slower further increase reaching a finite value after 5 to 7h. The initial and end values differ by a factor of 2 to 3. The results are explained in terms of sites with different reactivity assuming that the total number of isotactic sites is determined only after long times of contact with the inhibitor.So farc* was determined with14CO2or14CO by adding the inhibitor during the polymerization in the presence of propene and alkylaluminium;c* was calculated after short times of contact with the inhibitor, whereas the further steady increase in specific radioactivity was exclusively attributed to side reactions caused by reaction with propene and alkylaluminium.By this modified method we obtained for TiCl3·(1/3)AlCl3at 60°Ck̄p= 13 dm3/(mol·s) andc* = 0,012 mol Ti*/mol Titotal. Addition of a free Lewis base to the polymerization mixture increasesc* leavingk̄punchanged. In contrast to this, if TiCl3·(1/3) AlCl3is milled with a Lewis basek̄pcan be increased by a factor of ≈ 2,5 with lower or equalc* ‐values. The higher activity of extracted TiCl3‐catalyst is due to higherk̄pandc* ‐values as compared to tho

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830218

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractNon‐Newtonian viscosity could be explained by the Graessely entanglement viscosity theory modified by a frictional viscosity for moderately concentrated solutions of polydimethyIsiloxanes over a range of shear rates from lower to upper‐Newtonian flow. The expansion of a polymer molecule was kept under control by use of solvents with different dissolving powers of the polymer. The result shows that only the frictional viscosity is strongly related to the degree of expansion of a polymer molecule in solution and that Graessley's plots are independent of that. Extrapolation of the frictional viscosity versus concentration curves to 100wt.‐% show a common value of 0,09 Pa·s in spite of different degrees of expansion of the polymer molecules in solution. This common value was equal to the viscosity value for melt polymer with the same molecular weight as a polymer segment. It is concluded that the frictional viscosity is caused by solvent‐solvent, solvent‐polymer segment, and segment‐segment

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830219

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY