Thermal and mechanical properties of short‐segment block copolyesters and copolyether–estersWiley - Tập 23 Số 10 - Trang 2119-2147 - 1985
Janis L. Castles, Michael Vallance, J. M. McKenna, Stuart L. Cooper
AbstractThe effects of chain structure and processing variables on the microstructure and linear viscoelastic behavior of a series of copolyether–ester block polymers are described. In addition, the random copolyester analogs of the hard block are examined. The ester segments are composed of two isomers, poly(tetramethylene terephthalate) (PTMT) and poly(tetramethy...... hiện toàn bộ
Macromolecular nucleationWiley - Tập 12 Số 2 - Trang 255-263 - 1974
Bernhard Wunderlich, Aspy Mehta
AbstractThe rate‐determining step of crystallization of macromolecules from melt and solution is shown to be molecular nucleation. Molecular nucleation is described by using classical nucleation theory. Good agreement is found between the molecular nucleus size and the critical length of the rejected species. Molecular nucleation has a higher free‐energy barrier th...... hiện toàn bộ
Hydrogen bonding in nylon 66 and model compoundsWiley - Tập 23 Số 3 - Trang 537-555 - 1985
Dana Garcia, Howard W. Starkweather
AbstractFourier‐transform infrared spectroscopy was used to study the hydrogen bond‐breaking process in nylon 66 and two model compounds. The resulting enthalpy and entropy values indicated that while there is no interaction between adjacent amide groups in the polymer chain, there is, nevertheless, a substantial cooperative effect in the transverse hydrogen bond d...... hiện toàn bộ
A model for permeation of mixed gases and vapors in glassy polymersWiley - Tập 19 Số 10 - Trang 1513-1530 - 1981
William J. Koros, R. T. Chern, V. Stannett, H. B. Hopfenberg
AbstractA model is discussed which explains reported complex effects of feed composition and pressure on component permeabilities in high‐pressure gas separators based on glassy polymer membranes. A special form of Fick's law which accounts for the fact that penetrants in glassy polymers sorb into and diffuse through two different molecular environments provides th...... hiện toàn bộ
Diffusion‐controlled formation of porous structures in ternary polymer systemsWiley - Tập 17 Số 3 - Trang 477-489 - 1979
Claude Cohen, G. B. Tanny, Stephen Prager
AbstractWe propose a theory for the appearance of two‐phase structures during the formation of polymer membranes from a casting solution immersed in a coagulant bath. Our model is based on diffusion induced phase separation at the spinodal in the ternary nonsolvent‐solvent‐polymer system. A simplified treatment of the interdiffusion process by the diffusion layer m...... hiện toàn bộ
Some phenomenological consequences of the Doi–Edwards theory of viscoelasticityWiley - Tập 18 Số 1 - Trang 27-34 - 1980
William W. Graessley
AbstractDoi and Edwards have recently proposed a molecular theory for the dynamics of entangled polymer liquids based on a tube model to represent the mutual constraints on configurational rearrangement of the chains. Expressions for diffusion coefficient, plateau modulus, zero‐shear viscosity, steady‐state recoverable compliance, and terminal relaxation time can b...... hiện toàn bộ
Basic modes of three‐dimensional polymer crystal associations: Interlocked single crystals and crystal halvesWiley - Tập 13 Số 5 - Trang 909-927 - 1975
Bernard Lotz, A. J. Kovacs, J. C. Wittmann
AbstractTridimensional associations of lamellar polymer single crystals, grown from dilute solutions, are described as derived from their sedimentation patterns. These associations include interlocked crystals and decorating crystal halves. The origin of these crystals and their mutual orientation are discussed and tentatively interpreted by specific interactions b...... hiện toàn bộ