TECHNIQUES FOR MEASURING SURFACE AND BULK OPTICAL PROPERTIES OF POLYETHYLENE FILMS

A commercial rolled polyethylene film may be considered to consist of an air-side surface phase, a chill-roll surface phase, and a bulk component phase. Techniques are presented which allow the total light attenuated by the film to be divided into the attenuation caused by the individual phases. The experimental techniques are extremely simple and require no equipment other than a standard “Scattermaster.” Mathematical handling of the experimental data to yield the optical properties of the individual phases is conveniently carried out by determinate presentation of the data. The paper is primarily concerned with the development of surface optical techniques, but it is interesting to note that the light transmission of the surface phases frequently exceeds the bulk optical transmission. This indicates that surface roughness is not always the cause of poor optical quality of a polyethylene film. © 1969, American Chemical Society. All rights reserved.