CLEAVAGE REACTIONS IN CROSSLINKED URETHANE ELASTOMERS.
ONR technical rept.,
PRINCETON UNIV N J FRICK CHEMICAL LAB
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A study of network cleavage in a crosslinked polyurethane elastomer was made using the technique of stress relaxation. It was found that the data could be well represented by a sum of two exponential decay terms, and a theoretical explanation for this is presented. Stress relaxation in the polyurethane sample investigated is discussed in terms of the reversible cleavage of various linkages formed by isocyanate reactions. It is possible to identify two different decay processes and obtain activation energies for these processes. These are identified with cleavage of two different linkages. It is not possible at present to give a certain chemical identification of the linkages responsible for stress decay. Author