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Rheology of poly(vinyl chloride) plastisol: Effect of a particular nonionic cos...

The rheology of poly(vinyl chloride) plastisols is affected by many aspects of the formulations, such as type and concentration of each component, temperature and, perhaps most important, the polymer properties. Taking into consideration the surfactants normally present during the polymerization reaction, in this work, a different approach was followed. Besides the usual polymerization surfactants, a particular...

PVC paste rheology: Study of process dependencies

A plastisol is a dispersion (suspension) of fine particles of poly(vinyl chloride) with a plasticizer that is normally applied over a substrate, by spreading or coating, before the gelification and fusion into the final product. Because of the first step, the plastisol rheology study is a very important factor which has to be taken into consideration to determine and fine tune the process conditions. This work ...

Evaluation of flocs resistance and reflocculation capacity using the LDS technique

In a previous paper we have shown the added value of using LDS to monitor flocculation. It can supply, simultaneously, information on flocs size and structure and enlighten flocculation kinetics and mechanisms. In this paper, LDS is applied to study deflocculation and reflocculation processes of precipitated calcium carbonate (PCC) induced by cationic polyacrylamides, when different types of shear forces are ap...

Flocculation of PCC filler in papermaking: Influence of the particle characteri...

The influence of precipitated calcium carbonate (PCC) characteristics on the flocculation process and flocs structure was investigated in the presence of a linear, high molecular weight, cationic polyacrylamide of high charge density. For that, a commercial PCC sample was used, either as supplied (original PCC) or after a washing process (treated PCC). The PCC samples were characterised, and the flocculation pr...

PVC Paste Rheology: Polymer Properties and Viscoelastic Behaviour

Crystalline phase characterization of glass-ceramic glazes

The firing process of five raw crystalline frits was investigated by means of DTA, XRD, heating microscopy and dilatometry. The chemical composition of the frits was determined by FAAS, to define the main glass-ceramic system of each frit. The final crystalline structure detected for the sintered frits conformed to the temperatures for which transformations were obtained during heating. The existence of a relat...

A new approach to measuring solids concentration in mixing tanks

The solids concentration profiles in a mixing tank with mechanical agitation (axial flow impeller) have been measured using a light scattering technique associated with the refractive index matching procedure. Due to the high value of the refractive index of the particles, a new liquid mixture had been tested (70.2% ß-Pinen and 29.8% l-methylnaphtalene, v/v). The experimental profiles are compared with similar ...

Influence of shape on particle size analysis

The purpose of this paper is to study the influence of the shape of the particles on the response of the instruments used for their measurement. This was achieved by sizing three different particle shape materials with three different particle sizers. The differences in the size distribution data were used to calculate shape factors, defined as the ratio of two different equivalent diameters, The values of the...