Accession Number : AD0807822

Title :   PRESSURE EQUIPMENT FOR POLYMER CRYSTALLIZATION AND DTA UNDER PRESSURE.

Descriptive Note : Technical rept.,

Corporate Author : RENSSELAER POLYTECHNIC INST TROY NY DEPT OF CHEMISTRY

Personal Author(s) : Davidson, Theodore ; Wunderlich, Bernhard

Report Date : 30 DEC 1966

Pagination or Media Count : 25

Abstract : The design and use of two pieces of high pressure apparatus for polymer studies is discussed. One is a hydrostatic pressurestat of 50 cc internal volume for the preparation of large quantities of polymer crystals. The second apparatus is a special cell for performing differential thermal analysis (DTA) on polymers under high pressure and at high temperature. The preparative apparatus is designed for pressures up to 7,000 bars and temperatures up to 300 C. It has been used successfully to grow extended-chain crystals of polyethylene and its copolymers. The actual processes of melting and crystallization under pressure have been followed with the DTA apparatus up to 3,690 bars. Temperature vs. pressure curves have been obtained in this manner for polyethylene and for a copolymer of ethylene with butene-1. It is found that the degree of supercooling increases with pressure. Details are given of the design of both pressure systems and of the DTA cell and circuitry. The selection of materials and pressure fluids for high pressure apparatus is discussed. (Author)

Descriptors :   *INSTRUMENTATION), *CRYSTALLIZATION), (*PRESSURE, (*POLYMERS, DIFFERENTIAL THERMAL ANALYSIS, CRYSTAL GROWTH, HIGH PRESSURE, MELTING POINT, POLYETHYLENE PLASTICS, COPOLYMERIZATION, HYDROSTATIC PRESSURE.

Subject Categories : Physical Chemistry
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE