Processing‐morphology‐property studies of poly(vinyl chloride)

Singleton, C. J.; Isner, James D.; Gezovich, D. M.; Tsou, P. K. C.; Geil, P. H.; Collins, E. A.

doi:10.1002/pen.760140512

Cited by 39 publications

(4 citation statements)

References 14 publications

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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%

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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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Section: Introductionmentioning

confidence: 97%

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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“…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%

“…In the useful range of plasticizer concentration some crystallinity is maintained to temperatures of the order of 180-l90°C as demonstrated by the anomolous dependence of viscosity on molecular weight (92), Several authors (63,81,95) have demonstrated that viscosity shear rate curves, as a function of plasticizer concentration or temperature, could be superposed by suitable reduction procedures, In more recent studies (40),. however, it was faund that data was superposable at higher shear rates but that it was not possible to Superpose the low shear rate data obtained at 170-200°C on a sample having a fixed plasticizer level (40 phr), (Fig.…”

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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Vinyl Chloride Polymers

Summers¹

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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PVC has a large sales volume, second only to polyethylene. Its high chlorine content provides it with a high level of combustion resistance for building products, electrical enclosures, and wire and cable insulation. PVC has a unique ability to be compounded with a wide variety of additives, making it possible to produce materials in a range from flexible elastomers (the first thermoplastic elastomers) to rigid compounds, materials that are weatherable such as for siding and windows, compounds that have stiff melts and little elastic recovery for outstanding dimensional control useful in profile extrusion, or low viscosity melts which compete effectively with ABS and PC/ABS in thin‐walled injection molding parts such as computer monitor housings. Some PVC properties are attributed to unique morphology. The polymer precipitates from its monomer and grows into primary particles, which are later the melt flow units. Fusion into larger structures and product strength are controlled by breakdown of the grains into primary particles, by choice of additives, by amount of melting (temperature), and by number of tie molecules (molecular weight). The main type of polymerization is the suspension process, with significant polymerization made by the mass, solution, microsuspension, and emulsion processes. In the suspension process, the polymerization takes place in droplets of monomer suspended in water. From an environmental viewpoint, PVC is over 50% chlorine and as a result, is one of the most energy‐efficient polymers. PVC is an inherent flame retardant, and acts as a marker, enabling automated equipment to sort PVC containers from other plastics in the waste stream. Vinyl is recycled by at least 170 recyclers in the United States and Canada and more than 3,500 communities accept vinyl products in their recycling programs. The analysis from 155 large‐scale, commercial incinerator facilities found no relationship between the chlorine content of waste nor the addition of PVC, and dioxin emissions from combustion processes. New requirements from the U.S. EPA make scrubbers mandatory on all incinerators and are necessary whether or not PVC is present in the waste feed.

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Processing‐morphology‐property studies of poly(vinyl chloride)

Cited by 39 publications

References 14 publications

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

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

The rheology of PVC - An overview

Vinyl Chloride Polymers

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