A method for the determination of the internal particle structure of poly(vinyl chloride) suspension resins by analyses of vinyl chloride desorption rate data

Daniels, Charles A.; Longeway, G. D.

doi:10.1002/pen.760190304

Cited by 10 publications

(2 citation statements)

References 8 publications

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“…7, 7a, and 7b). The progressive growth of the compartments forming the grains, shown by electron micrographs camed out on grain sections, can also be determined by chromatographic methods involving desorption of organic solvents (6, 7). Table 1 indicates the change in the average size of these compartments obtained for a bulk PVC (AFNOR viscosity index 130) between 53 and 79 percent conversion.…”

Section: Growth and Densifying Of The Grainsmentioning

confidence: 99%

Morphology of mass PVC

Fischer¹

1984

J. Vinyl Addit. Technol.

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The evolution of the morphology of the PVC grains during the mass polymerization of vinylchloride monomer (VCM) has been studied. After nucleation of primary particles, a rapid flocculation step occurs that leads to grains. Continued polymerization inside the grains results in a progressive reduction in the pore volumes. Continuing the reaction to completion, if appropriate by adding a further amount of monomer, causes densifying of the grains leading, in some cases, to vitreous grains, which therefore are related to the cleanliness of the reactors used. The changes in the size of the constituent compartment affect both the process of preparation and the processing of the final product: degassing rate of monomer, and plasticizing rate. Thus, control of the degrees of conversion, associated with perfect cleaning of the reactor, which is easy in the case of the new vertical reactors, constitutes the key factors in the reproducibility of the process and the quality of the PVC produced.

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Section: Growth and Densifying Of The Grainsmentioning

confidence: 99%

Morphology of mass PVC

Fischer¹

1984

J. Vinyl Addit. Technol.

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“…(1) or its modifications, assuming some particle size distribution. 18 Under these circumstances our aim was to study the kinetics of monomer removal from suspension polyvinylchloride, treating it at elevated temperatures in a flow of inert gas.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of vinylchoride removal from polyvinylchloride by thermal treatment in a flow of inert gas

Peev

Trifonova

Peeva

1989

J of Applied Polymer Sci

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SynopsisThe kinetics of free monomer removal from powdered suspension polyvinylchloride at elevated temperatures in a nitrogen flow is studied. It is found that in fluidized bed the monomer concentration decreases linearly with time. This behavior cannot be explained by a model of molecular diffusion in single spheres because of particle degradation during the treatment. Conditions for complete vinylchloride removal from the polymer are proposed.

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Desorption of residual monomer from PVC resins in a fluidized bed drier

Bouaffar¹,

Yilmazer

Elbirli³

1994

J of Applied Polymer Sci

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SYNOPSISThe present study deals with the investigation of the desorption of vinyl chloride from various commercial and experimental suspension PVC resins in a laboratory fluidized bed drier simulating an industrial drier. The results show that PVC resins may differ widely in the rate a t which the monomer is desorbed. The rate of diffusion of the monomer is a function of the drying time, the fluidization air temperature, the porosity, and the amount of glassy particles in the PVC. The residual monomer content decreases with increasing air temperature, drying time, and resin porosity. After 105 min of drying with hot air at 80°C, the residual monomer content in the grade with the highest porosity is reduced from 3400 to 2 ppm, whereas for the grade with the lowest porosity, it is reduced from 4300 to 172 ppm on a dry basis. It appears that the resins of the high molecular weight grades are more porous and the low molecular weight grades contain a high proportion of nonporous or glassy particles and, hence, the desorption rate is smaller in these grades. The proportion of glassy particles and the size of glassy domains are estimated in this study by applying the experimental desorption data at long times to a desorption model. The model is useful in differentiating the interior structure of various PVC grades.

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A method for the determination of the internal particle structure of poly(vinyl chloride) suspension resins by analyses of vinyl chloride desorption rate data

Cited by 10 publications

References 8 publications

Morphology of mass PVC

Morphology of mass PVC

Kinetics of vinylchoride removal from polyvinylchloride by thermal treatment in a flow of inert gas

Desorption of residual monomer from PVC resins in a fluidized bed drier

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