Accession Number : ADA183367

Title :   Properties and Phase Transitions in Polyphosphazenes.

Descriptive Note : Technical rept.,

Corporate Author : PITTSBURGH UNIV PA SCHOOL OF ENGINEERING

Personal Author(s) : Magill,J H

PDF Url : ADA183367

Report Date : 28 Jul 1987

Pagination or Media Count : 11

Abstract : Polyphosphazenes were first synthesised towards the end of the last century. Now, a wide variety of polymers and copolymers with alkoxy, aryloxy and aminoxy groups have been synthesised. Recently, side chains have been connected directly to the backbone phosphorus modifying physical properties considerably. Variations in side group chemistry enables a wide span in properties to be covered ranging from glass temperatures approaching -100 C to melting points well above 300 C in some systems. Thermotropic behavior persists over a range of temperature. It was determined that degradation mechanisms were also important in determining thermal stability. For example, alkoxy phosphazenes degraded primarily via a chain unzipping process leaving little or no residue, whereas aryloxyphosphazenes mostly disintegrated through random chain scission (involving some chain transfer too) leaving a substantial residue.

Descriptors :   *PHOSPHAZENE, *POLYMERS, *PHASE TRANSFORMATIONS, CHEMICAL PROPERTIES, SYNTHESIS(CHEMISTRY), X RAY SCATTERING, ISOTROPISM, KINETICS, CREEP, REFRACTIVE INDEX, TOXICITY, THERMAL PROPERTIES, ALKOXY RADICALS, CHAINS, CHEMISTRY, COPOLYMERS, DEGRADATION, GLASS, MELTING POINT, PHOSPHAZENE, PHOSPHORUS, PHYSICAL PROPERTIES, TEMPERATURE, THERMAL STABILITY, TRANSFER

Subject Categories : Polymer Chemistry
      Plastics
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE