Analysis of Characteristics of Co-extrusion Multi-layer films with micron layer thickness
|關鍵字:||多層膜;共擠製;氣體阻障;multi-layer films;co-extrusion;gas barrier|
Since single-layer polymer film do not meet the requirements of new applications of packaging and optical components, multi-layer polymer films are widely used. However, most current applications of multi-layer polymer films use a small number of layers but with increased thickness. Recent studies of nanomaterials show that multi-layer polymer films with layer thickness in micrometer and nanometer scale has become a new trend of technological development. This study investigated how of layer thickness, number of layers, and the interface between layers affect the mechanical characteristics and gas barrier ability while layer thickness does not change the thickness of multi-layer films, increasing the number of layers significantly decreases layer thickness to the micron scale. This study developed a new mold design that can separate and expand co-extruded polymer films by using a co-extrusion system that has been described previously. The mold enables repeated overlay of two polymer layers to reduce layer thickness and increase the number of layers. The specimen are then compared by optical microscope, and a gas permeability experiment is performed to determine the relationships among number of layers, layer thickness, and gas barrier ability in the multi-layer films. Finally, a gas permeability experiment is performed using size exclusion method to generalize the relationship between gas permeability, numbers of layers, and layer thickness, and to establish a numerical model of gas permeability. The experiments indicate that polypropylene is an effective water vapor barrier, and its oxygen barrier characteristics resemble those of polyamide. Overall, gas permeability revealed a strong correlation with the number of layers of multilayer films. The experimental results of this study provide a reference for further study of the functional mechanisms of polymer multilayer films.