Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz
Dec 1990
Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz
William MacKnight
Thermal, dielectric, and mechanical relaxation measurements on miscible blends of poly-
benzimidazole(PBI)and a polyetherimide (PEI, Ultem 1000)prepared by solution casting
from dimethylacetamide (DMAc) reveal a number of structurally related features. Annealing
below the glass transition temperature induces an enthalpy relaxation process typical of
single-phase glasses of nonequilibrium structure. Dielectric relaxation experiments on
samples annealed at ambient conditions reveal two relaxation processes below 400°C.At
lower temperatures (50-2OO0C), the desorption of water is observed. Above 200°C in the
first run, a composition-dependent relaxation is seen at the highest frequencies ( 100 kHz)
while a relaxation approximately independent of composition appears in the …
Dynamic Mechanical And Dielectric Properties Of An Epoxy Resin During Cure, William Macknight, Walter X. Zukas, N. S. Schneider
Dec 1982
Dynamic Mechanical And Dielectric Properties Of An Epoxy Resin During Cure, William Macknight, Walter X. Zukas, N. S. Schneider
William MacKnight
No abstract provided.
Dynamic Mechanical And Dielectric Properties Of Phosphonylated Polypentenamers And Their Hydrogenated Derivatives, William Macknight, D. Rahrig, C. Azuma
Dec 1977
Dynamic Mechanical And Dielectric Properties Of Phosphonylated Polypentenamers And Their Hydrogenated Derivatives, William Macknight, D. Rahrig, C. Azuma
William MacKnight
Dynamic mechanical and dielectric properties of substituted polypentenamers with phosphonate side groups and their hydrogenated derivatives have been studied. Methyl esters, acids, and salts were investigated at two concentrations, 6.5 and 11.1 mole percent. In the unhydrogenated derivatives, one principal relaxation, labeled fl, is observed mechanically in the temperature range from -160 to 100°C. This {J relaxation arises from micro-Brownian segmental motion accompanying the glass transition. Its temperature is substantially affected by the substituent concentration while its breadth is affected by the chemical nature of the substituent. An extended "rubbery plateau" region exists in the acid and salt derivatives. The …
Compatibility Of Poly(2, 6-Dimethyl-1,4-Phenylene Oxide) (Ppo)/Poly(Styrene-Co-4-Chlorostyrene) Blends. Ii. Dielectric Study Of The Critical Composition Region, William Macknight, R. E. Wetton, J. R. Fried, F. E. Karasz
Dec 1977
Compatibility Of Poly(2, 6-Dimethyl-1,4-Phenylene Oxide) (Ppo)/Poly(Styrene-Co-4-Chlorostyrene) Blends. Ii. Dielectric Study Of The Critical Composition Region, William Macknight, R. E. Wetton, J. R. Fried, F. E. Karasz
William MacKnight
Random copolymers of styrene and 4-chlorostyrene bridging the composition range from compatibility to incompatibility with poly(2,6-dimethyl-1,4-phenylene oxide) have been blended with the latter polymer. Dielectric constant and loss data are reported for the key blends containing 60% by weight of the copolymers. Dielectric relaxation spectra were found to be far broader for the blends than for the parent copolymers and this is interpreted primarily as arising from a wide range of local concentrations which are present even in the "compatible" blend. Phase separation produces a characteristic shoulder on the high-frequency side of the relaxation which is interpreted in terms of …
Dielectric And Mechanical Relaxations In Ethylene-Acrylic Acid And Ethylene-Methacrylic Acid Copolymers, William Macknight, F. A. Emerson
Dec 1971
Dielectric And Mechanical Relaxations In Ethylene-Acrylic Acid And Ethylene-Methacrylic Acid Copolymers, William Macknight, F. A. Emerson
William MacKnight
The dielectric relaxation behavior of ethylene-carboxylic acid copolymers has been studied over the frequency ° range of °SO Hz to 10 f Hz and over the temperature range of -160 C to+ 100 C. The copolymers studied consisted of four acrylic acid and two methacrylic acid copolymers of varying acid content. In the temperature and frequency region investigated, two dielectric dispersions occur and these are labelled B' and yin order of decreasing temperature. The B' dispersion may be quantitatively accounted for on the basis of the orientation of free carboxylic acid groups. The concentration of these groups is assessed from …
