An instrument for online measurement of structural orientation in translucent polymer sheets

In many applications of polymer materials, a high tensile strength is requi red. There is a definite correlation between the degree of orientation of m olecular chains achieved in the orientation process and the tensile strengt h obtained. In this work, we describe design and fabrication details of a d evice, 'Laser based polymer orientation grader', for online measurement of the degree of orientation to obtain a high consistent tensile strength as o utput. This instrument has been designed making skilful use of the optical anisotropic property of the oriented polymer strip. The principle is based on the fact that the spatial distribution of laser light passing through th e translucent polymer sheet depends on the degree of orientation of long ch ain molecules in the sheet. The method has potential online application in monitoring and controlling of anisotropy in manufacturing processes.