Polyethylene crystallized under the orientation and pressure of a pressure capillary viscometer. Part I

Abstract

Abstract High-density commercial polyethylenes have been crystallized under the combined orientation and pressure effects available in the Instron capillary rheometer. The samples so formed were found to have a high degree of crystal perfection and crystal orientation in combination with the unusual property of transmitting visible light. The samples consisted of fibrils aligned parallel to the axis of flow in the rheometer System. The procedure for forming the crystal structure is elucidated. X-Ray, differential scanning calorimetry,. and stereo-scannig electron microscopy were utilized to initiate a study of the structure. Evidence is presented that indicates the presence of an extended-chain component in the crystal structure.