Very small-angle X-ray scattering by plasticized polyvinyl chloride (PVC)

Shtarkman, B.P.; Lebedev, V.P.; Yatsynina, T.L.; Kosmynin, B.P.; Gerasimov, V. I.; Genin, Ya.V.; Tsvankin, D.Ya.

doi:10.1016/0032-3950(72)90283-3

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…The small and widely distributed crystallites in PVC act as physical crosslinking sites in an amorphous pool of chains 10–15. This physical network persists even in plasticized form 16–18. This is because the plasticizer molecules mainly solvate the intercrystalline amorphous regions19, 20 and leave the crystallites intact.…”

Section: Introductionmentioning

confidence: 68%

“…At very high plasticizer loadings, however, some melting could be induced. A reduction in crystallinity from 11 to 4% was reported with no significant changes in d‐spacings in the unit cell or average crystallite size as the plasticizer loading was increased from 0 to 150 phr (per hundred resin) 18. As evidenced by wide‐angle X‐ray diffraction (WAXD) patterns, the microcrystallites in this network, both in unplasticized and plasticized form, could be oriented 13, 21, 22.…”

Section: Introductionmentioning

confidence: 88%

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Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage

Yalcin

Çakmak

2005

J Polym Sci B Polym Phys

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The structural evolution during uniaxial stretching of poly(vinyl chloride) films was studied using our real time spectral birefringence stretching machine. The effect of clay loading and the amount of plasticizer as well as the rate effects on the birefringence development and true mechanical response are presented with a final model summarizing the molecular phenomena during stretching. Mechano-optical studies revealed that birefringence correlated with mechanical response (stress, strain, work) nonlinearly. This was primarily attributed to the preexisting strong network of largely amorphous chains connected via small crystallites that act as physical crosslinking points. These crystallites are not easily destroyed during the high-speed stretching process as evidenced from the birefringence-true strain curves along with the X-ray crystallinity measurements. At high speeds, the amorphous chains do not have enough time to relax and hence attain higher orientation levels. The crystallites, however, orient more efficiently when stretched at slow speeds. Apparently, some relaxation of the surrounding amorphous chains helps rotate the crystallites in the stretching direction. Overall birefringence is higher at high stretching speeds for a given true strain value. When the nanoparticles are incorporated, the orientation levels are increased significantly for both the crystalline and amorphous phases. Nanoplatelets increase the continuity of the network because they have strong interaction with the amorphous chains and/or crystallites. This in turn helps transfer the local stresses to the attached chains and increase the orientation levels of the chains. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 724 -742, 2005 Keywords: uniaxial; poly(vinyl chloride) (PVC) nanocomposites films; poly(vinyl chloride) (PVC) orientation; birefringence ucts, the polymer is often oriented in the rubbery state and undergoes morphological and structural changes which in turn impart significant changes on its physical, mechanical, optical, and barrier properties and their anisotropy.To attain the desired set of properties, the link between the processing conditions, for example, temperature, rate, and extent of stretching, and the structural characteristics, for example, degree of orientation, crystal size, and shape evolution, should be well established. However, during fast deformation processes, structural transitions may occur rapidly and are rather difficult to elu-

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Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 88%

Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage

Yalcin

Çakmak

2005

J Polym Sci B Polym Phys

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“…Plasticized PVC samples exhibit a more intense interference maximum which most likely originates from the specific penetration of the plasticizer into the noncrystalline regions, resulting in an enhanced scattering contrast between the crystalline and noncrystalline regions. [21][22][23][24] The presence of unplasticized regions in plasticized PVC has also been demonstrated by means of electron microscopy.24,26 Plasticizer contents up to 50 % (v/v) do not seem to affect the structural order of PVC.24,!26,27…”

Section: Introductionmentioning

confidence: 97%

“…13 On the other hand, a reasonable agreement is obtained on the basis of a tentative model allowing specific penetration of plasticizer into the noncrystalline regions, as suggested in the literature. [21][22][23][24] For this purpose, an expression for the dependence of the invariant on the volume fraction ^ptot has been derived (eq 2), where the scattering densities of the crystalline and noncrystalline phases in rigid PVC have been put equal relative to the scattering density of TDN. This assumption is reasonable in view of the observed small scattering density difference between crystalline and noncrystalline regions.…”

Section: Introductionmentioning

confidence: 99%

Structural aspects of suspension poly(vinyl chloride). Small-angle neutron scattering of rigid and plasticized suspension PVC

Scherrenberg¹,

Reynaers²,

Mortensen³

et al. 1993

Macromolecules

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A comprehensive SANS study on both rigid and plasticized suspension PVC demonstrates the presence of superstructural order in this polymer. Comparison of the experimental scattering invariant data with a tentative two-phase model points to specific penetration of the plasticizer in the noncrystalline regions of PVC. Thermal experiments manifest the gradual and thermoreversible melting of the crystalline regions at temperatures above 80-90 °C. Uniaxial deformation experiments on plasticized PVC confirm the existence of a heterogeneous network-structure in PVC where the crystalline tie-points act as physical cross-links. The observed anisotropic "butterfly" scattering pattern of a uniaxially stretched sample indicates the formation of concentration inhomogeneities as a consequence of the random distribution of the crystalline tie-points in plasticized PVC. The anistropy of the scattering pattern gradually disappears on heating, probably resulting from the increasing mobility of the plasticized interstitial medium.

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“…Both mechanical and thermal history have also been observed to have a pronounced effect on the flow curves as well as on the physical appearance and properties quite analogaus to rigid compaunds (89)(90)(91)(92) but it has only been recently (34,40,93,94) that attempts have been made to relate morphology to the flow behavior, This is not surprising since tecbniques to handle liquid-like syste~. (plasticized surfaces) have only recently been developed.…”

Section: Pvc 1o4mentioning

confidence: 99%

The rheology of PVC - An overview

Collins¹

1977

Pure and Applied Chemistry

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-Three aspects of the rheological behavior of PVC are considered. These are (a) particulate flow which occurs below the true crystalline melting point, (b) true melting flow which occurs at or above the melting point and (c) the flow of PVC compounds. The effect of structural differences, resulting from different polymerization temperatures employed in preparing different molecular weight polymere, on the melt viscosity and flow activation energy is reexamined and new data presented to unconfound the effect of syndiotacticity and molecular weight. The three flow behaviors of PVC is shown to be presented by three distinct flow regions. Because of thermal instability, the true melt flow region is only achieved with difficulty. However, in commercial operations this latter state is seldom, if ever, achieved in rigid formulations. The effect of compounding additives, especially lubricants and plasticizers and the importance of thermal and mastication history on the flow behavior is discussed with reference to the flow mechanism.

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Very small-angle X-ray scattering by plasticized polyvinyl chloride (PVC)

Cited by 11 publications

References 5 publications

Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage

Molecular orientation behavior of poly(vinyl chloride) as influenced by the nanoparticles and plasticizer during uniaxial film stretching in the rubbery stage

Structural aspects of suspension poly(vinyl chloride). Small-angle neutron scattering of rigid and plasticized suspension PVC

The rheology of PVC - An overview

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