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  • 1
    Digitale Medien
    Digitale Medien
    Steric energy of the rotational state of the side groups of poly(vinylnaphthalene) (1981)
    s.l. : American Chemical Society
    Macromolecules 14 (1981), S. 1831-1833 
    Details
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ma50007a045
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  • 2
    Digitale Medien
    Digitale Medien
    Electric dipole moment of ethylcellulose, in 1,4-dioxane and in benzene (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 3109-3117 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The electric dipole moments per repeating unit of ethylcellulose (EC) of various molecular weights were determined by dielectric measurements at 1 kHz (μL) and at 1 MHz (apparent moment, μH) in 1,4-dioxane and benzene. The numerical values were μL = 5,23 D (= 17,45.10-30 C·m) and μH + 2,72 D (= 9,07.10-30 C·m) for 1,4-dioxane, and μL = 4,81 D (= 16,04.10-30 C·m) and μH = 2,42 D (= 8,07.10-30 C·m) for benzene, respectively. μL and μH were almost independent of the molecular weight in both solutions. The persistence dipole moment μq was estimated to be 13,6 D (= 45,36.10-30 C·m) in 1,4-dioxane, and 13,4 D (= 44,70.10-30 C·m) in benzene, respectively, and the flexibility of the EC chain was discussed.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1981.021821117
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  • 3
    Digitale Medien
    Digitale Medien
    Dielectric behaviour of poly(sulfonyl-1-butylethylene) in concentrated solutions (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2455-2464 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Measurements of the dielectric relaxation of three poly(sulfonyl-1-butylethylene)s, (PSB), of different molecular weights were carried out in benzene solutions of polymer contents from 3,0 to 50,0 wt.-%. It was found that the distribution parameter of the dielectric relaxation time was constant above a critical polymer contents and the activation energy increased with polymer contents. The observed relaxation time was analyzed by Fröhlich's theory assuming limiting relaxation times. The lower limit in the relaxation time, τ1, was independent of polymer contents above the critical polymer contents, in contrast to the upper limit relaxation time, τ2, which depended on polymer contents. The polymer contents dependence of the critical frequency below and above the critical polymer contents was interpreted by the free volume effect. The unperturbed molecular dimension at the critical polymer contents was also discussed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1981.021820909
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  • 4
    Digitale Medien
    Digitale Medien
    Conformational analysis of poly(oxymethylene) (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 3533-3543 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The conformational energies of the lower members of poly(oxymethylene), 2,4-dioxapentane and 2,4,6-trioxaheptane were estimated by the empirical force field method. The gauche states of the internal rotation around the skeletal C—O bonds were successfully predicted to be of lower energies in both molecules. In order to calculate the unperturbed dimension and dipole moment of poly(oxymethylene), rotational isomeric state approximations were made by using the results obtained from the force field calculations on 2,4,6-trioxaheptane. The first-order interaction energy was estimated to be a large negative value, and the second-order interaction energies for g±g± had non-zero values. Although these parameters were significantly different from those estimated earlier, they reproduced the observed results fairly well. Thus the “gauche effect” of poly(oxymethylene) was explained by taking account of the effects contributed by the lone pairs of electrons on the oxygen atoms. As adopted in this study, the procedure joining the empirical force field method to the statistical mechanical one was shown to be effective for the investigation of many sorts of configuration-dependent properties of chain molecules.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1981.021821216
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  • 5
    Digitale Medien
    Digitale Medien
    Conformational analysis of polyoxyethylene using empirical force field methods (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 1285-1293 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Conformanational energies of various oligo (oxyethylene) isomers were calculated by the empirical force field method, and statistical mechanics calculations of the chain dimensions and the dipole moments were carried out. The results are seriously different from those obtained for poly (oxymethylene). Although the first-order steric interactions in POE are of the same order of magnitude as those in n-alkane chains, the second-order interactions are significantly different. The second-order interactions arising from rotations around two consecutive bonds of OCH2CH2OCH2 in g± g∓ conformation have greatly reduced steric repulsions. It was found that the reduced second-order interaction plays an important role in the configurationdependent properties of POE. The agreement of the calculated values for the unperturbed dimensions and the temperature coefficients obtained from the force field method with experimentally observed ones is fairly good.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1983.021840619
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  • 6
    Digitale Medien
    Digitale Medien
    Dielectric behavior of ethylcellulose in concentrated solutions (1980)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 181 (1980), S. 1967-1978 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Measurements of dielectric relaxation were made for a series of solutions of ethylcellulose in benzene. The concentrations ranged from 0,5 to 20 wt.-% and two polymers of different molecular weight were used. The dielectric dispersion was measured over the frequency range of 30 Hz - 3 MHz at 30 - 50°C. The concentration dependence of the critical frequency below and above the critical concentration is interpreted by the free volume effect. It was found that the dielectric relaxation times are constant above the critical concentration and that the activation energy increases with concentration. The observed relaxation time is analyzed by Fröhlich's theory assuming two limiting relaxation times. The lower limit in the relaxation time, τ1, is concentration-independent above the critical concentration, in contrast to the upper relaxation time τ2, which depends on concentration. These relaxation times, τ1 and τ2, however, are interpreted by the same free volume effect. The unperturbed molecular dimension at the critical concentration is also discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1980.021810916
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  • 7
    Digitale Medien
    Digitale Medien
    Estimation of chain molecular dimension of poly(2-methylpent-1-ene sulfone) at critical polymer contents by dielectric measurements (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1219-1223 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Dielectric measurements were made in the frequency range from 30 Hz to 3 MHz for a series of the solutions of poly(2-methylpent-1-ene sulfone) (PMPS) having two different molecular weights in benzene at 30°C. The unperturbed chain molecular dimension was estimated from dielectric relaxation time at the critical polymer contents, Ccr. This value of the unperturbed dimension was much higher than that from the intrinsic viscosity measurement. The dielectric motion at Ccr involves simultaneous co-operative reorientations of about three spheres. The number of the spheres of reorientation may be related to the flexibility of the molecular chain of the polymer. The ratio of two effective volumes of the polymer obtained from the unperturbed chain molecular dimension and from the dielectric relaxation time, τm agreed with that of the two effective volumes obtained from the K value in Onogi's treatment and from the τm value.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1982.021830515
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  • 8
    Digitale Medien
    Digitale Medien
    Electric dipole moment of cellulose- and amylose derivatives (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1343-1351 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The electric dipole moments (per repeating unit) of cellulose acetate and tricarbanilate, and amylose acetate and tricarbanilate were determined in 1,4-dioxane solution at 30°C. The parallel component of the moment to the chain contour was also estimated for samples of various molecular weights, and they were almost independent on molecular weight, indicating no excluded volume effect on the dipole moment. The persistence dipole moment, and monomer dipole component along the chain contour for cellulose derivatives were about 50% smaller than those for amylose derivatives. The relation between the dipole moment and the chain dimension is discussed for cellulose- and amylose derivatives.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1982.021830527
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  • 9
    Digitale Medien
    Digitale Medien
    Concentration dependence of the dielectric behavior of poly(2-methyl-1-pentene sulfone) in benzene solution (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 2491-2499 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Dielectric measurements over a wide frequency range (30 Hz to 3 MHz) were made on solutions of poly(2-methyl-1-pentene sulfone) (PMPS) in benzene at various polymer mass fractions up to 40 wt.-%. The dielectric relaxation time increased linearly with increasing polymer concentration. A breaking point in the plot of the relaxation time against the polymer concentration appeared at a critical polymer concentration. The dielectric behavior below and above the critical polymer concentration was interpreted on the basis of the theory of free volume effect. The observed dielectric relaxation time was analyzed by Fröhlich's theory, assuming two limiting relaxation times, τ1 and τ2. The lower limit, τ1, which corresponds to the segmental motion, was independent of the polymer concentration above the critical polymer concentration, but in contrast, the upper relaxation time corresponding to the motion of the molecule as a whole, τ2, depended strongly on the polymer concentration.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1982.021831019
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  • 10
    Digitale Medien
    Digitale Medien
    13C NMR studies of thermotropic liquid crystalline poly(γ-alkylaryl L-glutamate)s (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 345-354 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The molecular motions of three kinds of poly(γ-alkylaryl L-glutamate)s (1-3) having a phenylene or a biphenylylene group and alkyl groups with various length, containing 6 to 22 carbon atoms, were investigated by means of 13C NMR spectroscopy as a function of temperature. The observed range of temperature covers the “crystal-to-liquid-crystal” phase transition temperature, Tm. It was found that these phase transitions are caused by an increase of the motions of aromatic or alkyl groups in the side chain, depending on the samples, and that the motion of main chains of polymers 1-3 with α-helical conformation does not occur on the NMR time scale at least up to 160°C. The degree of the mobility of the alkyl chain in the side chain of 1-3 depends on their length above Tm.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1990.021910208
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