The origin of charge on nascent poly(vinyl chloride) particles in monomer

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

doi:10.1016/0032-3861(79)90236-2

Cited by 21 publications

(8 citation statements)

References 8 publications

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“…As mentioned previously, the parameter p , in eq. (17), was introduced in order to relate the total electric charge, Q i , to the particle radius, Ri . In this way, we can account for the variation of #o; with the size of the primary particles.…”

Section: Results On the Electrostatic Stability Of Primary Particlesmentioning

confidence: 99%

“…Tornell et a1.l' proposed the empirical expression (17), which relates the primary particle radius to the total particle charge, in order to investigate the electrostatic stability of PVC primary particles. Thus, for Qi = 6.27 X Coulombs and Ri = 0.15 X m, the numerical value of C, will be equal to C, = 6.27 X 10-'8(1.5 X lo-?…”

Section: Calculation Of Surface Potentialmentioning

confidence: 99%

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Electrostatic and steric stabilization of PVC primary particles

Kiparissides¹,

Moustakis²,

Hamielec³

1993

J of Applied Polymer Sci

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SYNOPSISProblems related to the formation and stability of primary particles in VCM suspension and bulk polymerization were theoretically analyzed, based on the DLVO (DeryaguinLandau-Venvey-Overbeek) and HVO ( Hesselink-Vrij-Overbeek ) theories of stability of colloidal systems. In the absence of secondary stabilizers, PVC primary particles were solely stabilized by negative electric charges, as a result of the presence of HCl formed by a chain transfer reaction of chloride radicals to PVC polymer chains. The dependence of the stability of primary particles on the ionic strength of the medium, temperature, and total particle charge was quantitatively investigated in terms of the stability ratio and the particle coalescence rate constant. The steric stabilization of primary particles, arising from the addition of surfactants or polymers to the monomer phase, was examined, using the HVO theory. It was shown that PMMA improved the stability of primary particles and, thus, could alter the particle agglomeration kinetics. The effects of molar mass and the amount of the adsorbed PMMA, as well as the influence of solvent quality on the steric stabilization of primary particles, were also investigated. The experimental results, published on the electrostatic and steric stabilization of PVC primary particles, were in good agreement with the theoretical predictions obtained in this study. 0 1993 John Wiley & Sons, Inc.

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Section: Results On the Electrostatic Stability Of Primary Particlesmentioning

confidence: 99%

Section: Calculation Of Surface Potentialmentioning

confidence: 99%

Electrostatic and steric stabilization of PVC primary particles

Kiparissides¹,

Moustakis²,

Hamielec³

1993

J of Applied Polymer Sci

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“…Unstabilized particles of this size are too unstable to be observed by photon correlation spectroscopy. Rance and Zichy (1979) have shown that the particle size and number density of primary particles formed by diffusion-controlled coagulation of basic particles should approach The fact that the primary particles are monodisperse (see Tornell and Uustalu, 1982) and stable toward coagulation for a considerable growth period suggests that they are stabilized. Electrophoretic measurments have shown that the primary PVC particles are negatively charged (see Rance and Zichy , 1979).…”

Section: B Particle Formation At Low Conversionmentioning

confidence: 97%

Recent Developments in PVC Polymerization

Törnell

1988

Polymer-Plastics Technology and Engineering

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“…For the system PVC/VCM the value of the Hamaker's constant was taken as 5 x 10 -2' J [13]. The energy of repulsion can be calculated from the DLVO theory, or for particles smaller than the Debye length by a modified Coulomb's law [15].…”

Section: A Colloidal Stability Of Pvc Particlesmentioning

confidence: 99%

“…Thus, as growth proceeds, a decrease in the surface potential occurs and, therefore, a decrease in the colloidal stability. The origin of the charge was postulated to be due to the specific adsorption of chloride ions at the VCM/PVC interface [13,14]. These chloride ions may be the product of either PVC dehydrochlorination or the decomposition of VCM peroxide formed during the reaction of VCM with the residual oxygen.…”

Section: Introductionmentioning

confidence: 99%

Aggregation phenomena in the suspension polymerization of VCM

Diamadopoulos

Zoubourtikoudis

Kiparissides

1990

Colloid & Polymer Sci

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In the suspension polymerization of VCM, insoluble polymer particles are formed inside the monomer droplets. The growth and aggregation of these particles are responsible for important polymer properties, such as porosity. It is well established that the most characteristic polymer particles, the primary particles, are of a narrow distribution with a size (diameter) ranging from 0.10-0.20 vm. This work studied the formation of primary particles based on the aggregation phenomena that take place inside a monomer droplet. This was done by formulating a population balance equation, which was based on the following considerations: a) polymerization occurs in both the monomer and the polymer phases; b) there is continuous formation of the basic particles in the monomer phase; c) the growth of the polymer particles occurs as a result of both polymerization in the polymer phase and aggregation of the particles; d) the colloidal properties of the particles that are responsible for the aggregation phenomena were considered to be the net result of attraction and repulsion energies.It was shown that for particles carrying a constant charge it was not possible to predict the formation of primary particles of size 0.10-0.20 t~m. The particle size distribution had a mode diameter equal to the diameter of the basic particles. Consequently, the particle charge was allowed to vary in a way proportional to the particle radius raised to a power coefficient. For values of the coefficient greater than zero, i. e., when the particle charge increased during polymerization, the aggregation of the basic particles was efficient enough to result in the formation of large primary particles.

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The origin of charge on nascent poly(vinyl chloride) particles in monomer

Cited by 21 publications

References 8 publications

Electrostatic and steric stabilization of PVC primary particles

Electrostatic and steric stabilization of PVC primary particles

Recent Developments in PVC Polymerization

Aggregation phenomena in the suspension polymerization of VCM

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