TY - JOUR
T1 - Annealing-induced morphological changes in segmented elastomers
AU - Van Bogart, J. W.C.
AU - Bluemke, D. A.
AU - Cooper, S. L.
N1 - Funding Information:
The authors wish to thank the following individuals for supplying the materials used in this study: Dr E. A. Collins of the Diamond Shamrock Company who supplied the ET and ES series material during his association with B. F. Goodrich; Dr James C. West of Allied Chemical Corporation who synthesized the UPCL series material while a postdoctoral fellow at the University of Wisconsin; Laura E. Lerner who synthesized the HPCL based polymers for her MSc Thesis at the University of Wisconsin; Dr Charles S. Schollenberger of the B.F. Goodrich Company who supplied the ETUU material; Dr Lamar L. Harrell Jr. of E. I. DuPont de Nemours and Company who sent us the piperazine material; and Dr Gerald M. Estes of the E. I. DuPont de Nemours and Company who gave us the segmented polyester material. The authors wish to acknowledge support of this work by the polymer programme of the National Science Foundation through Grant DMR 78-11662.
PY - 1981/10
Y1 - 1981/10
N2 - Thermal analysis has been used to study annealing-induced ordering in segmented elastomers. Twelve segmented elastomers were studied each having approximately 50% by wt hard segment content. Seven general classes of materials were examined including polyether and polyester polyurethanes, polyether polyurethane-urea, and polyether-polyester. Materials were slow cooled (-10°C min-1) from the melt to an annealing temperature (-10°, 20°, 60°, 90° or 120°C) where they were annealed (16, 12, 8, 6 or 4 days, respectively). Annealing was followed by slow cooling (-10°C min-1) to -120°C after which a d.s.c. experiment was run. In general, annealing resulted in an endothermic peak at a temperature 20°-50°C above that of the temperature of annealing. This phenomenon was observed in both semicrystalline and amorphous materials. The closer the annealing endotherm was to a crystalline endotherm without exceeding it in temperature, the larger its size. Annealing endotherms resulted from hard or soft segment ordering. Only one annealing endotherm was observed for a given annealing history, even though in some materials hard and soft segments could exhibit annealing-induced morphological changes. Hard segment homopolymers were studied yielding results similar to the block polymers containing shorter sequences of the same material. This suggests that annealing-induced ordering is an intradomain phenomenon not associated with the interphase between domains, or necessarily dependent on the chain architecture of segmented elastomers.
AB - Thermal analysis has been used to study annealing-induced ordering in segmented elastomers. Twelve segmented elastomers were studied each having approximately 50% by wt hard segment content. Seven general classes of materials were examined including polyether and polyester polyurethanes, polyether polyurethane-urea, and polyether-polyester. Materials were slow cooled (-10°C min-1) from the melt to an annealing temperature (-10°, 20°, 60°, 90° or 120°C) where they were annealed (16, 12, 8, 6 or 4 days, respectively). Annealing was followed by slow cooling (-10°C min-1) to -120°C after which a d.s.c. experiment was run. In general, annealing resulted in an endothermic peak at a temperature 20°-50°C above that of the temperature of annealing. This phenomenon was observed in both semicrystalline and amorphous materials. The closer the annealing endotherm was to a crystalline endotherm without exceeding it in temperature, the larger its size. Annealing endotherms resulted from hard or soft segment ordering. Only one annealing endotherm was observed for a given annealing history, even though in some materials hard and soft segments could exhibit annealing-induced morphological changes. Hard segment homopolymers were studied yielding results similar to the block polymers containing shorter sequences of the same material. This suggests that annealing-induced ordering is an intradomain phenomenon not associated with the interphase between domains, or necessarily dependent on the chain architecture of segmented elastomers.
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U2 - 10.1016/0032-3861(81)90250-0
DO - 10.1016/0032-3861(81)90250-0
M3 - Article
AN - SCOPUS:0019623326
SN - 0032-3861
VL - 22
SP - 1428
EP - 1438
JO - Polymer
JF - Polymer
IS - 10
ER -