| Abstract: | A new method of blending two polymers with very different molecular weights, i.e. different melt viscosities, in which the polymer mixture is forced to pass through a nozzle with a conical taper is proposed in this study. High density polyethylenes with very high and very low molecular weights were used as the samples in the blending process, and the parameters that affected the homogeneity of the blended polymers were studied. The homogeneity was found to be better at a lower shear rate, smaller orifice diameter, higher compression ratio of the cross-sectional area of the nozzle entrance and orifice, and a small length-to-diameter ratio of the orifice. This blending process, the nozzle blend, was found to make the droplets of a high molecular weight component extend to thin fibers along the conical section of the nozzle. The nozzle blend system has been proved to be useful in obtaining both macroscopic and microscopic homogeneity, and has been estimated to be comparable to a few minutes of roll-mill blending. |
