US Patent 7096728 Polymer melt and elastomer extension fixture

A system for making extensional measurements on a sample includes an armature, a motor drive shaft, a moveable cylinder, and a fixed cylinder. The motor drive shaft is attached to the armature. The moveable cylinder is mounted on the armature. The sample is stretched between the moveable cylinder and fixed cylinder by the rotation of the moveable cylinder around the axis of the fixed cylinder and rotation of the moveable cylinder about its own axis. The resistance of the sample produces a torque on the moveable cylinder and the fixed cylinder. The torque is measured on the moveable cylinder or on a transducer shaft attached to the fixed cylinder. The system is adaptable to a commercial rotational rheometer.