Contribution of polyalky(meth)acrylates to the design of PVC melt viscosity

The shear viscosity of poly(vinylchloride) (PVC) at 200°C can be decreased by at least one order of magnitude by the addition of as little as 5 wt% poly n-alkyl-(meth)acrylates (PMA) of a much lower dynamic viscosity than PVC. For this effect to be observed, the polymeric additive must be immiscible with PVC at 200°C. The average size of the dispersed phases is observed in the range of 0.5 to 5 m; size fluctuation in this domain has no significant effect. When these conditions are met, there is a linear increase in the shear viscosity ratio blend/PVC from 0.2 to 1.0 with increasing logarithmic values of the dynamic viscosity ratio of the additive over PVC [(log(/)) from -4 to -1].