Small‐angle x‐ray study of deformed bulk polyethylene

Gerasimov, V. I.; Genin, Ya.V.; Tsvankin, D.Ya.

doi:10.1002/pol.1974.180121006

Cited by 48 publications

(23 citation statements)

References 20 publications

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“…As mentioned above, the observed periodicity along the nanofibrils is consistent with SAXS data [30]. Broadening of the SAXS reflections in the direction perpendicular to the fiber axis can only be used to monitor the occurrence of nanofibrils if the adjacent crystal domains are uncorrelated [42,43]. From the half-width of the corresponding WAXS peaks, it was shown that the 2, dimension decreased upon drawing to a value of about 12 nm [36].…”

Section: Discussionsupporting

confidence: 70%

Nanofibrillar surface structures of gel‐drawn UHMW‐polyethylene tapes

et al. 1996

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The fibrillar structure of gel-drawn ultrahigh molecular weight polyethylene was studied by scanning force microscopy (SFM), transmission electron microscopy (TEM) and 'H-NMR. Periodically striped 20-50 nm wide nanofibrils were depicted at the surface of the ultradrawn tapes. A periodicity of about 25 nm was observed independently of the draw ratio in the range 10 = A S 70. This is consistent with the long period derived from SAXS experiments. The stripes were more pronounced at low draw ratios and a short range interfibrillar correlation was detected in that case. Based on variations in the 'H-NMR relaxation times and segment orientation, it is concluded that structural defects are concentrated within small domains inside the crystallites and that the striped structure originates from defect layers within the fibrillar crystallites.

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Section: Discussionsupporting

confidence: 70%

Nanofibrillar surface structures of gel‐drawn UHMW‐polyethylene tapes

et al. 1996

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“…Correlation is detected only in the machine direction, and the broadening of the meridianal streak in the equatorial direction is due to the small lateral dimension of crystals. Further deformation, finally, leads to a four‐point pattern after release of stress which is due to tilted basal planes of the crystals, with the orientation of the chain kept in the direction of the meridian 48–51. The tilt, however, is mainly initiated on backward deformation as a result of the relaxation process because in situ deformation studies without relaxation did not reveal such clear four‐point patterns during deformation 52.…”

Section: Resultsmentioning

confidence: 99%

Directional atherectomy of a calcified lesion using a new atherectomy device

Reimers

Stanković

Prati

et al. 2002

Cathet Cardio Intervent

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“…The positions of the fibrils in neighbouring fibrils may be assumed to be uncorrelated. Calculations and interpretations based on this model, to which we will refer as the model of inclined lamellar fibrils, were given by Gerasimov and coworkers (13,14). (In a recent paper Gerasimov et al (15) furthermore considered the possibility of the lamellae in neighbouring fibrils being correlated.…”

Section: The Calculation and Comparison Of Correlation Functions Basementioning

confidence: 98%

A small angle X-ray scattering study of polyethylene fibres, using the two-dimensional correlation function

Vonk

1979

Colloid Polymer Sci

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From the general principles of diffraction theory it follows that Fourier transformation of the function describing the distribution of the diffracted X:ray intensity in reciprocal space leads to a function in direct space representing the autoconvolution of the electron density variations in the diffracting object. As on the one hand this function contains all the information that is hidden in the diffraction pattern, and on the other hand can be more readily interpreted in terms of structural details than the intensity function itself, it is often used in the solution of structures from X-ray diffraction data. In small angle X-ray scattering (SAXS) it is usually scaled to have the value 1 in the origin; it is then called the correlation function. Its general properties have been discussed by Porod (1) and by Debye, Anderson and Brumberger (2); the application of a onedimensional correlation function to the lamellar structures occurring in isotropic semicrystalline polymers was recommended by Vonk and Kortleve (3).In this paper the use of two-dimensional correlation functions in the study of SAXS from fibres of uni-axial symmetry is discussed. Here the situation differs from the one encountered in isotropic polymers in that the basic structure in the isotropic polymers (stacks of alternating crystalline and amorphous layers) might be taken for granted, whereas there is no general agreement on the basic structure occurring in polymer fibres.Many of these substances show a four-point SAXS pattern, which has been explained in different ways, as is to be discussed below. Therefore in the present case the correlation function should in the first place serve in asserting the most appropriate model, and secondly in finding the correct values of the various parameters involved. The potentiality of the correlation function in these respects will be demonstrated in the analysis of the diffraction pattern from a cold drawn and subsequently annealed fibre of low density polyethylene. The approach followed is to compare the 'observed' correlation function, obtained by Fourier transformation of the observed intensity function, with 'calculated' correlation functions, based on the different models that have or can be proposed. Furthermore, also calculated intensity functions were obtained by Fourier transforming the calculated correlation functions; the comparison of these with the original observed intensity functions was however made in a qualitative way only. Experimental and computational detailsThis was a commercial low density polyethylen of the type Stamylan 2800, manufactured by DSM. Its density after compression molding (cooling rate 40 °C/min.), as determined according to method ISO 1183 D, was 0.920; the melt flow index, determined according to method ISO R 292, amounted to 0.30 gr/10 min. From a compression molded sheet dumbbell shaped specimens were made that were drawn at room temperature at a rate of 2.5 cm/min, to fracture at an extension of 700%. Annealing was achieved in conditions where the samples were free...

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Small‐angle x‐ray study of deformed bulk polyethylene

Cited by 48 publications

References 20 publications

Nanofibrillar surface structures of gel‐drawn UHMW‐polyethylene tapes

Nanofibrillar surface structures of gel‐drawn UHMW‐polyethylene tapes

Directional atherectomy of a calcified lesion using a new atherectomy device

A small angle X-ray scattering study of polyethylene fibres, using the two-dimensional correlation function

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