Accession Number : ADA186278

Title :   Structure-Property Relationships in Thermoplastic Elastomers IV. Dynamic Mechanical Relaxations in Poly(Dioxolane), Poly(Butyltrioxocane) and Poly(Propylene Oxide) Polyurethanes.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS UNIV AMHERST DEPT OF POLYMER SCIENCE AND ENGINEERING

Personal Author(s) : Chen, James C ; Rho, M K

PDF Url : ADA186278

Report Date : 15 Aug 1987

Pagination or Media Count : 30

Abstract : Dynamic mechanical measurements had been made on polyurethanes of a range of hard segment content (HSC) obtained form alpha, omega-dihydroxy derivatives of poly(propylene oxide) of 2000 to 12,000 MW coupled with MDI and TDI with hydroxyethyl phthalamide chain extenders. N-methylated chain extender was used to investigate the effect of hydrogen bonding. A board gamma transition was observed between - 100 deg and -115 deg attributable to the local motion of methylene sequences with a distribution of relaxations. The B transition between -55 deg and -72 deg is influenced by the degree of hydration; the a transition occurs at nearly the same temperatures for all the TPE's independent of HSC and thermal history. The magnitude of the loss tangent peak corresponds to the glass transition. An alpha transition at higher temperature is sensitive to the structure of soft segment, HSC and thermal history.

Descriptors :   *ELASTOMERS, *POLYMERS, *PROPENES, *THERMOPLASTIC RESINS, DISTRIBUTION, DYNAMICS, GAMMA RAYS, GLASS, HISTORY, HYDRATION, HYDROGEN BONDS, LOSSES, MEASUREMENT, MECHANICAL PROPERTIES, METHYLENES, MOLECULAR STRUCTURE, MOTION, OXIDES, PEAK VALUES, PHYSICAL PROPERTIES, POLYURETHANE RESINS, RELAXATION, SEQUENCES, TANGENTS, TEMPERATURE, THERMAL PROPERTIES, TRANSITIONS

Subject Categories : Elastomers and Rubber

Distribution Statement : APPROVED FOR PUBLIC RELEASE