TY - JOUR
T1 - Structure-property behaviour of segmented polyether-MDI-butanediol based urethanes
T2 - effect of composition ratio
AU - Abouzahr, S.
AU - Wilkes, G. L.
AU - Ophir, Z.
N1 - Funding Information:
The authors wish to acknowledge the financial support of the National Science Foundation - Polymer Materials Division - for this study.
PY - 1982/7
Y1 - 1982/7
N2 - The structure-property relationship of a systematic series of segmented polyurethanes was investigated segment was 4,4′-diphenylmethane diisocyanate (MDI) extended with 1,4-butanediol, and the soft segment was 2000 Mw poly (tetramethylene oxide) ether. X-ray studies reveal that some hard segment segment was 2000 mW poly (tetramethylene oxide) ether. X-ray studies reveal that some hard segment crystallization occurs at high hard segment content (45%). In addition, other morphological changes take place as the hard segment fraction is increased. The texture changes from that in which little such domain content exists at low hard segment levels (15%), to that in which the polymer has an interlocking domain morphology at high hard segment content (35 and 45%). Preferable elastomeric properties (low hysteresis, high extension) can be obtained when isolated hard segment domains exist (25% hard segment). Thermal treatment of the samples results in domain disruption and hard-soft segment mixing. However, this phenomenon, and the consequent time-dependent structure recovery as the material is allowed to age, is composition dependent. In general, crystalline domains, when present, are disrupted the least while the fastest recovery is displayed by samples with noncrystalline domain texture. This behaviour can be explained qualitatively in terms of kinetic diffusion effects relative to the thermodynamic driving forces for phase separation.
AB - The structure-property relationship of a systematic series of segmented polyurethanes was investigated segment was 4,4′-diphenylmethane diisocyanate (MDI) extended with 1,4-butanediol, and the soft segment was 2000 Mw poly (tetramethylene oxide) ether. X-ray studies reveal that some hard segment segment was 2000 mW poly (tetramethylene oxide) ether. X-ray studies reveal that some hard segment crystallization occurs at high hard segment content (45%). In addition, other morphological changes take place as the hard segment fraction is increased. The texture changes from that in which little such domain content exists at low hard segment levels (15%), to that in which the polymer has an interlocking domain morphology at high hard segment content (35 and 45%). Preferable elastomeric properties (low hysteresis, high extension) can be obtained when isolated hard segment domains exist (25% hard segment). Thermal treatment of the samples results in domain disruption and hard-soft segment mixing. However, this phenomenon, and the consequent time-dependent structure recovery as the material is allowed to age, is composition dependent. In general, crystalline domains, when present, are disrupted the least while the fastest recovery is displayed by samples with noncrystalline domain texture. This behaviour can be explained qualitatively in terms of kinetic diffusion effects relative to the thermodynamic driving forces for phase separation.
KW - Polyurethane
KW - block copolymers
KW - elastomers
KW - segmented copolymers
KW - structure-property
KW - thermoplastic elastomers
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U2 - 10.1016/0032-3861(82)90411-6
DO - 10.1016/0032-3861(82)90411-6
M3 - Article
AN - SCOPUS:0020161709
SN - 0032-3861
VL - 23
SP - 1077
EP - 1086
JO - Polymer
JF - Polymer
IS - 7
ER -