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Influence of molecular weight on the thermal and mechanical properties of polyurethane elastomers based on 4,4′‐diisocyanato dicyclohexylmethane
Author(s) -
Hespe Hans F.,
Zembrod Alfred,
Cama Farhad J.,
Lantman Christopher W.,
Seneker Stephen D.
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070441118
Subject(s) - elastomer , materials science , polyurethane , deformation (meteorology) , composite material , relaxation (psychology) , strain rate , slippage , kinetics , deformation mechanism , polymer chemistry , psychology , social psychology , microstructure , physics , quantum mechanics
Two series of segmented polyurethane elastomers based on 4,4′‐diisocyanato dicyclohexylmethane were investigated with respect to their thermal properties and deformation behavior. We used a crystallizable soft segment, 1,4‐poly(tetramethylene glycol), for one series and a noncrystallizable soft segment, 1,2‐poly(propylene glycol), for the other. Both systems exhibited mechanical self‐reinforcement that depended strongly on the deformation rate. We propose a mechanism for the observed stress/strain behavior in terms of two competing processes: (1) the buildup of orientation caused by deformation and (2) the loss of orientation caused by plastic slippage and segmental relaxation during deformation. The kinetics of these processes depend stronly on the deformation rate and overall molecular weight.