Morphology Development during Melt Processing of Immiscible Polymer Blends

Abstract

Polymer blends have provided an efficient way of meeting new requirements for materials. The alternative to blending is to synthesize new polymers, which not only involves exorbitant costs but also cannot fulfill industrial demands. According to the recent survey by Utracki [1], about 30 % of all plastics sold today contain more than one polymer, and this fraction continues to increase each year. It has been predicted that blends will comprise 90 % of all plastics by the year 2000. Nearly all of these polymer-polymer blends are immiscible; yet the resulting multiphase morphologies can produce desirable properties. The final product performance of the multiphase polymer systems strongly depends on resulting morphologies. Polymer blends are prepared by melt mixing in industrial field, although many experimental studies have been carried out by casting from solution. It is well recognized that the results obtained from the experiments on casting from solution do not necessarily agree with those obtained from melt mixing without solvent. Thus, the investigation of the morphology development during melt mixing is of great importance for the prediction and the control of the final blend morphology. Moreover, knowledge of the mechanisms of morphology development would be useful for the design of processing equipment with improved mixing capabilities.