摘要:

AbstractRecent progress in the theory of scattering by spherulites of crystalline polymers is reviewed. The consequences of arbitrary optic axis orientation, periodicity of optic axis orientation and of spherulite deformation are described. The transmission of light by a film of a crystalline polymer having spherulitie or lower degrees of order of crystalline orientation is discussed. A theory of the scattering of light from such a film having nonrandom correlation in crystalline orientation is developed. The dependence of the scattered intensity on the polarization directions of the incident and scattered light is shown to depend upon a parameter which characterizes the nonrandomness.

ISSN:0449-2994    

DOI:10.1002/polc.5070130104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractThe observed small angle light scattering (SALS) from deformed spherulites is described by the theory of an anisotropic spheroid in an isotropic medium. Experimental verification of the theory, based on SALS data from both photographic and photometric measurements on isotactic polypropylene films, is presented. The theory led to a method for experimentally determining the extension ratio of the deformed spherulite and the radius of the original undeformed spherulite from the SALS pattens.

ISSN:0449-2994    

DOI:10.1002/polc.5070130105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractCreep and creep recovery experiments were carried out on films of linear polyethylene containing ringed spherulites. Photographic light‐scattering patterns obtained during the experiments from the rings and spherulites were analyzed to determine the quotient of the extension ratio in the direction of stress to that at right angles to the stress direction, Xy/γz. Comparison with results derived from mechanical strain measurements indicated stronger time dependencies of creep and creep recovery as measured by light scattering than as determined from mechanical strain measurements for a sample of Marlex 6035 crystallized at 105°C. The results arc interpreted in terms of a model of spherulite response which incorporates chain tilting. The probable dependence of the deformation process on the crystallization conditions and the type of deformation experiment is pointed

ISSN:0449-2994    

DOI:10.1002/polc.5070130106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractA variety of films were examined by low angle laser light scattering to yield information on the size, shape, and orientation of superstructure. Films of poly(ethylene terephthalate) and polypropylene give distinctive scattering patterns in the form of two‐ and four‐leaf clovers which change with polarization direction, stretching, heat setting, and heat relaxation. Changes in pattern geometry vary systematically with film properties, x‐ray, and polarized infrared structural parameters. In one‐way oriented poly(ethylene terephthalate) films, the quadrant, leaves tend toward the equator and elongate with increased draw, taking on a fiberlike appearance, whereas with two‐way drawn films the leaves shift away from the equator and patterns become more circular with increased second direction draw. Melt‐pressed, quenched, unnucleated, polypropylene films show a characteristic spherulitic type pattern. The higher the quench temperature, the larger the spherulites become. Calculated spherulite diameters increase with quench temperature up to 15m for temperatures of 60°C. Upon drawing, the patterns elongate owing to Spherulite deformation and internal reorganization of crystallites, taking on a fiberlike geometry. Nucleated and slowly cooled resins show very little scattering and no spherulitic quadrant leaves. Heat setting usually led to the appearance of new pattern features characteristic of new structures. Heat relaxation tended to smear out the Scatterning patterns as a result of the disappearance of su

ISSN:0449-2994    

DOI:10.1002/polc.5070130107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractA now, extremely Simple, technique for visually observing light scattering from polymer films is presented. The technique employs a polychromatic divergent light source, in some cases with no polarizers, as the entire apparatus. It is shown that patterns characteristic of scattering from the spherulites and the rings, including multi‐ple‐Order scattering from the latter, can be observed by this method. Applications to monitoring of spherulite size during polymer processing are briefly discussed. It is shown that by simple collimation the method can be extended to photographic recording of scattering patterns and that after determination of the effective wavelength of the source the patterns can be quantitatively analyzed. It is demonstrated that wide angle scattering patterns comparable to those obtained with a laser can be obtained in comparatively short exposure ti

ISSN:0449-2994    

DOI:10.1002/polc.5070130108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractAn experimental evaluation of the light scattering from two water‐swollen cellulose gels and the corresponding solvent‐exchanged cellulose gels has been made. The two gels were prepared from a commercial viscose by methods which gave different degrees of swelling. The solvent exchanged gels were finally imbibed with silicone fluids whose refractive indices (n) covered the range 1.40–1.59. The Debye‐Bueche theory for scattering from a heterogeneous solid was applied to the data. The observed scattering could be interpreted in terms of refractive index or density fluctuations which were less for the sample with lover degree of swelling. The average periodicity of the density fluctuations increased asnof the imbibition fluid in the solvent‐exchanged samples approached the value,na, for the amorphous regions and maximized in this region. Comparative lateral order distribution information could be derived from the data. From the results it could be shown that the water‐swollen gel is more homogeneous then after solvent exchange but the difference was less for the less swollen system. The evidence collected supports the idea that cellulose gels are, to a first approximation, three‐phased systems involving high order and low order regions as well as micropores. Electron micrographs of thin sections of the solvent‐exchanged gels served to confirm

ISSN:0449-2994    

DOI:10.1002/polc.5070130109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractLight‐scattering data from solvent‐exchanged, highly swollen gel cellophane were compared with the scattering theory for a three‐component system (crystalline fraction, amorphous fraction, and imbibition liquid) originally developed for the scattering of x‐rays. A rather good agreement, between theoretical and experimental data is obtained in angular dependence and dependence on the refractive index of the imbibition liquid. But the calculated “zero” angle intensities are some orders of magnitude larger than the observed values. This effect must be due to the variation of the internal electric field which is influenced not only by the local polarizability but also by the shape of the region under consideration and by the polarizability of the surrounding area. This effect does not occur with x‐rays since the refractive index is then unity. With visible light one must conclude that the absolute scattering intensity, I(O) is much more affected than the angular dependence which is sufficiently well described by the composite correlation function of the three‐c

ISSN:0449-2994    

DOI:10.1002/polc.5070130110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractWhen heated to high temperatures under zero tension, some of the molecules in oriented nylon 66 filters change from the elongated to the folded conformation, with no change in crystal orientation. This transformation is shown by a combination of structural and physical property measurements: wide and small angle x‐ray diffraction, broad and narrow line nuclear magnetic resonance, sonic modulus, density, shrinkage, and tensile properties. A fortyfold increase of the intensity of the discrete small angle x‐ray diffraction is obtained for treatments between 160‐and 255°C. as well as an increase of the length of the long period and a change from a smeared four‐point to a sharp two‐point diagram. Wide angle x‐ray measurements show little change in crystallite orientation for treatments up to 250°C. even though much shrinkage occurs. Disruption of some type is observed by sonic measurements, as would be expected if new folds occurred. An increase of density and x‐ray crystallinity confirms that heating causes much additional crystallization. The high temperature NMR spectra for these more crystalline yarns show a much larger proportion of fluidlike segments. Shrinkage of the yarns during the heating appears to be governed by the number of folds which are introduced. Tensile strength is reduced by this introduction o

ISSN:0449-2994    

DOI:10.1002/polc.5070130111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

摘要:

AbstractIt is tempting to correlate the discrete small angle x‐ray diffraction (SA) spacings obtained using polymers crystallized from the melt with the thickness of the lamellae present in the sample. There is a good correlation of SA spacing and the electron microscope (EM) observed thickness for polymers crystallized from solution. However, a review of available data in which SA and EM observations have been made on the same sample (for polyethylene, polyoxymethylene, polychlorotrifluoroethylene, and polyethylene oxide) show that the largest HA spacing is not in agreement with the EM observed thickness. In several of the polymers the second largest spacing, which is often not an order of the largest, is in reasonable agreement with the EM value. Possible causes of these discrepancies are discusse

ISSN:0449-2994    

DOI:10.1002/polc.5070130112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY

ISSN:0449-2994    

DOI:10.1002/polc.5070130103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1966

数据来源: WILEY