From isocyanates and hydroxyl compounds

An extensive review of the reactions of isocyanates with hydroxy compounds, including a thorough survey of the catalysis and kinetics of the reactions, was published in 1962 [116]. Other relatively recent surveys of the subject of special interest include those of Farkas and Mills [117] and Lyman [118]. Other reviews which are of special supplemental value with respect to control of the reactions in polyurethane formation include those of Johnson [119] and Saunders and Frisch [120]. 

This survey will repeat only that information in earlier reviews which is judged to be necessary for an over-all understanding of the subject. The major emphasis will be on data on polyurethane formation (rather than reaction of monofunctional model compounds) which have been published within the period of 1962 to 1969, with partial coverage of 1970. For more details on earlier publications the reader is directed to the references given above. 

A satisfactory understanding of polyurethane formation requires an understanding that in addition to the main reaction of urethane formation, other reactions of isocyanates are possible, especially in the presence of certain catalysts. With the proper selection of temperature and catalyst these side reactions can usually be avoided, but the experimentalist should 

This reaction is discussed in more detail in the later section on polyurea formation. Its importance includes a consideration of the subsequent reaction to form a biuret 

Carboxyl groups, which may be present in certain polyesters, give primarily amides 

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