Assessments of the amount of light scattering or haze caused by the abrasion of transparent plastics when measured with a collimated beam hazemeter at reduced beam diameter are shown to be affected by differences in amount of beam reduction. The data presented illustrate that most of the light scattered from a sample abraded with a Taber Abraser® is found in the angular cone between 0 and 2.5°. This is also the region subtended by the 1.3° annulus between the lightbeam and the exit port of a hazemeter conforming to ASTM Test for Haze and Luminous Transmittance of Transparent Plastics (D 1003). For this reason, measurement of abraded specimens is very sensitive to the beam geometry of the hazemeter.
Since conventional (nonabraded) specimens produce very diffuse scattering patterns, changes in beam diameter and thus the size of the annulus do not significantly affect haze readings. However, to obtain reproducible results on abraded specimens, modification is required to the geometry of the hazemeter so that the image of the entrance window is focused at the exit port of the sphere. Good interlaboratory agreement was obtained when suitably modified hazemeters were used to measure a set of polymethylmethacrylate (PMMA) specimens. Modifications that have been made to ASTM Test for Resistance of Transparent Plastics to Abrasion (D 1044) are discussed.
Description
Discusses the physical tests necessary to obtain data relevant to an intended application. The text demonstrates clearly how one analyzes end-use requirements and correctly chooses tests and conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.