Automatically testing polymeric material - focussing pulsating laser beam via revolving mirror on to successive points on moving material and analysing radiation spectrum produced

摘要

The properties of polymers are determined by using a pulsating laser beam focussed on to the surface of the material so as to produce at intervals fusion and radiation which is characteristic the elements or molecules in the fused material, this radiation is used to produce a spectrum of lines or mol. bands which is detected, the results are converted into appropriate concn. values from the intensities of selected radiations of certain elements/modecules. The surface is divided grid-fashion by relative movement of the end of the intermittent laser beam, and each unit of the grid has a test point formed by the laser beam focus, the fusion produced at each such point is evaluated before each following laser pulsation and the series of concn. values obtd. are stored, from the results the curve of concns. over at least part of the surface is determd. in testing the partic. points in at least two successive checks, a significantly larger number of the points is omitted during one interval in time than in another, for the same area of surface. ADVANTAGE - The method enables the distributions of concns. (of elements or mols) to determine properties of e.g. plastic materials or rubber on-line during the prodn. processing or testing operations.