Solid‐state structure of melt blended incompatible polymeric mixtures involving poly(vinyl chloride)

Abstract

Abstract Poly(vinyl chlorides) having different melt viscosities were melt blended with several different incompatible polymers using a two‐roll mill and a Brabender Plasticorder. The properties of the mixtures can be easily reproduced from batch to batch only if the viscosity of the components does not change during the mixing process. Within this limitation, the order of addition of the components during the mixture preparation does not have a significant influence on the mixture properties. The shear storage modulus of the incompatible mixtures in the temperature range between the Tg 's of the components varies with the difference in component viscosities at the temperature of mixing. The moduli of these mixtures are compared to moduli calculated using Kerner's equations. Based on this comparison it is concluded that in any incompatible mixture the component having the lower melt viscosity at the temperature of processing tends to form a continuous phase in the mixture. The greater is the viscosity difference, the greater is this tendency. The viscosity of one component relative to the other can be changed by changing the molecular weight of the components and/or the temperature of mixing.