COMPARISON OF THE EFFECT OF CHOSEN COMMERCIAL SUSPENSION STABILIZERS ON SOME PROPERTIES OF POLY(VINYL CHLORIDE).Part I.EFFECT ON GRAIN SIZE DISTRIBUTION

摘要

The effects of the compositions of binary mixtures of selected commercial suspension stabilizers on suspension PVC particle size distribution (r.w.z.) and some other properties (K-value,bulk density,plasticizer absorption) were compared.The subjects of investigations were:3 primary poly(vinyl alcohol) (PVAL) stabilizers of very similar hydrolysis degree (71-72 %),one secondary PVAL and methylhydroxypropylcellulose derivative classified as primary stabilizer.Binary mixtures differing in types and parts of components were prepared from these products.Suspension polymerization of vinyl chloride was carried out in laboratory scale at temperature dependent on required K-value of a polymer (53degC,57degC and 64degC).PVC particle size distribution has been investigated (Figs.1-11) and the properties mentioned above (Tables 1-3) for the polymers prepared at each temperature.The mixtures of stabilizers allowing producing the products showing most advantageous (from the processing point of view) granulometric characteristics,that is,of most narrow r.w.z.and possibly minimal part of oversized and undersized grain,were picked.The results show that commercial stabilizers of even very similar characteristics can not be swapped because only the proper choice of their types and amounts let produce PVC of good processing properties.