The life-cycle of the two phase system in vinyl chloride polymerisation

Rance, D.G.; Zichy, E.L.

doi:10.1351/pac198153020377

Cited by 26 publications

(9 citation statements)

References 3 publications

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“…Formation of primary particles has been studied by many investigators (16, [59][60][61][62][63][67][68][69][70][71][72][73][74][75][76][77]. From turbidimetric measurements, Boissel, et al (63), suggested that polymer precipitates from the monomer phase at conversions a s low as 0.001 %.…”

Section: Physical Phenomenamentioning

confidence: 99%

Suspension, bulk, and emulsion polymerization of vinyl chloride—mechanism, kinetics, and reactor modelling

Xie

Hamielec

Wood

et al. 1991

J. Vinyl Addit. Technol.

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A review of relevant microscopic processes, both chemical and physical, which occur during suspension, bulk and emulsion polymerization (both before and after pressure drop) is given. The state of the art of kinetic modelling of monomer consumption rate, reactor pressure, molecular weight and short and long chain branching development and polymer chain microstructure is illustrated. The effects of diffusion-controlled termination and propagation reactions and the significant decrease in initiator efficiency and decomposition rate constant at high monomer conversions on the relative rates of various chemical reactions are discussed. The application of temperature programming and semibatch operation are emphasized. Finally, attempts to model polymer particle morphology are described.

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Section: Physical Phenomenamentioning

confidence: 99%

Suspension, bulk, and emulsion polymerization of vinyl chloride—mechanism, kinetics, and reactor modelling

Xie

Hamielec

Wood

et al. 1991

J. Vinyl Addit. Technol.

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“…Assuming that the ionic species of the unknown electrolyte present in the pure VCM is a 1:1 electrolyte, and that the corresponding ions have ion mobilites in the same order of magnitude as Bu4 N+ and BFT, the concentration of ions in the "pure" VCM was estimated as I tmml/1. This ion concentration corresponds to a reciprocal Debye length of around 1 x 107 1 --m-. The reader should note that the assumptions underlying this calculation have no direct experimental verification.…”

Section: Debye Length and Particle Stabilitymentioning

confidence: 99%

“…These particles have an initial size of about 0.1 ~rn [1], and they are stabilized by electrostatic forces during a certain growth period after their formation [2,3]. The size and number of particles formed are closely connected with the particle stability [4,5].…”

Section: Introductionmentioning

confidence: 99%

Colloidal stability of PVC primary particles in vinyl chloride

Törnell

Uustalu

Jönsson

1986

Colloid & Polymer Sci

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Abstract:The electrostatic contribution to the colloidal stability of PVC primary particles (R = 0.15 ~) dispersed in vinyl chloride, was calculated using models based on the Coulombic interactions and the DLVO theory. The calculations were based on: a) the particle charge as obtained from literature data on the electrophoretic mobility of PVC primary particles in VCM and b) on estimates of the Debye length as obtained from measurements of the electrical conductivity of VCM and of solutions of Bu4NBF 4 in VCM.The calculations showed that particle stability would decrease with particle size (experimentally-observed behaviour), only if the particle charge increased with size at a lower rate than in proportion to particle radius.The calculations also suggest that particle growth may be governed by a competitive growth mechanism of electrostatic origin. Particle growth is assumed to occur by absorption of many small, weakly charged basic particles from the monomer phase. According to the calculations, the electrostatic interaction between primary and basic particles may be such that the growth of the smaller primary particles is favoured over that of the larger ones.

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“…Not being soluble in its own monomer, PVC macromolecules precipitate, forming coils very close to each other, because the transfer reaction time is much shorter than the time it takes the macromolecules to diffuse away, according to calculations performed by several researchers (Rance and Zichy, 1981). As a consequence, the coils tend to flocculate and form so-called basic particles, with a diameter that has been estimated around 0.01-0.02 m (Allsopp, 1981;Rance and Zichy, 1981). The latter step can be considered the nucleation step of a process of growth of PVC particles in each droplet both by agglomeration and by polymerization.…”

Section: Vcm Suspension Polymerization Overviewmentioning

confidence: 99%

Mathematical modeling of the porosity of suspension poly(vinyl chloride)

Márquez¹,

Lagos²

2004

AIChE Journal

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A mathematical model that describes the effect of conversion and polymerization temperature on the porosity of suspension poly(vinyl chloride) is proposed. The model considers that the packing of the primary particles that develop in the polymerizing drop begins at a conversion at which the particles become motionless. The model considers the morphology of the primary particles as a group of particles with a particular sphericity that form a network whose porosity decreases as conversion increases. Furthermore, the model considers the effect on porosity of the desorption of residual monomer and the difference in contraction and

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The life-cycle of the two phase system in vinyl chloride polymerisation

Cited by 26 publications

References 3 publications

Suspension, bulk, and emulsion polymerization of vinyl chloride—mechanism, kinetics, and reactor modelling

Suspension, bulk, and emulsion polymerization of vinyl chloride—mechanism, kinetics, and reactor modelling

Colloidal stability of PVC primary particles in vinyl chloride

Mathematical modeling of the porosity of suspension poly(vinyl chloride)

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