Method and apparatus for measuring melt elasticity of polymers

• Main Author: MAXWELL; BRYCE
• Format: Patent
• Language: English
• Published: 06.06.1978
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

An apparatus and method for measuring the elastic properties of polymer melts and polymer solutions including the placement of a specimen of the material to be tested, within the intervening space between two members both of which are capable of low friction rotation about a common axis, further including a drive apparatus to forcibly rotate one member about the axis to shear the specimen, also including the measuring of the force required to shear the specimen, in order to determine the modulus of elasticity, yield stress and steady state viscosity of the specimen, further releasing the member not forcibly rotated and measuring the recoverable strain and rate of strain recovery by measuring the motion of the released member as a function of time for the purposes of determining the elastic characteristics of the specimen, further including a light source directed along the axis of rotation of the members into an optical fiber along the center line thereof so shaped to emerge in a direction parallel to the axis of rotation but at a point distant therefrom, the light source being adapted to be turned off and on as a fucntion of time in a predetermined manner such that a photograph of the end of the optical fiber distant from the axis of rotation determines the position of the released member as a function of time thereby measuring the rate of strain recovery and the total amount of strain recovery of the specimen.