Microstructure development during the injection molding of PET/LCP blends

liquid crystal polymer (LCP) was blended with polyethylene terephthalate (P ET) in different concentrations to improve the barrier properties of PET in injection stretch blow molded bottles. The improvement depends on the micr ostructure developed at various stages of the process. In this work, the em phasis is on the injection molding stage of the preform. The characteristic s and number of morphological layers were directly related to the amount an d type of LCP in the blend and the location within the preform. It was foun d that at 10% LCP, three morphological layers were found across the thickne ss of the part, while at 30% LCP, five morphological layers could be identi fied. The USP structure can be classified into four types: droplets, thick rods, thin fibrils and ribbons. Each morphological layer is made up of one or more types of structures. The evolution of one type of structure to anot her depends on the particular flow regime ongoing at various locations in t he mold. This microstructure development, during the flow, was examined in detail.