Polyethylene melt adsorption and desorption during flow on high-energy surfaces: Characterization of postextrusion die wall by laser scanning confocal fluorescence microscopy

摘要

In this paper we report results that delineate the state of polymer adsorption on high-energy surfaces following no-slip and slip flow. The experiments were performed by precoating a slit die wall made of a silicon wafer with a thin layer of fluorescent dye-labeled polyethylene (FPE) and then extruding through the slit die a nonfluorescent polyethylene both below and above the interfacial stick-slip transition (SST). Using a laser scanning confocal fluorescence microscope, the postextrusion die walls were examined to check for the existence of the preadsorbed FPE. It is shown that the preadsorbed fluorescent polyethylene (PE) chains were still present after the stick-slip transition. The presence of adsorbed polymer chains following slip flow supports the previously proposed "cohesive" mechanism for the SST of PE on highly adsorbing surfaces. [References: 23]