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A. Balas, R. Lisowska


Changes in urethane prepolymers with free isocyanate groups caused by n-butyllithium


Polimery 1983, No 12, 432



DOI: dx.doi.org/10.14314/polimery.1983.432

Summary

The results of studies on the effect on n-butyllithium on the changes insolubility, lR-spectra and degree of crosslinking of urethane prepolymers containing free isocyanate groups and prepared from oligo(ethylene adipate) and toluene 2,4-diisocyanate or diphenylmethane 4,4-diisocyanate have been presented. The urethane elastomers formed under these conditions contain a soluble fraction and afraction insoluble in common solvents. An increase of the molar ratio of n-BuLi/NCO in the range of 0.103—0.541 causes a decrease in the content of insoluble fraction and in the degree of elastomer crosslinking. A similar effect has an increase of the molar ratio of NCO/OH in the step of prepolymer synthesis. A mechanism of the observed changes has been proposed which explained the observed dependencies.


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