PURPOSE: To provide the subject polymer which is prepd. by reacting an oligomer poly(alkylene carbonate) polyol with a specified active hydrogen ingredient contg. compd. and does not give a bad effect to environment as it is decomposed naturally and is useful as a nonionic surfactant.

CONSTITUTION: An objective polymer is prepd. by reacting an oligomer poly(alkylene carbonate) polyol (A) a mono- or di-functional value active hydrogen ingredient contg. compd. (B) selected from alcohols, carboxylic acids, mercaptans, amides, prim. or sec. amines and substd. phenols. As the ingredient A, poly(ethylene carbonate) diol, or the like, are pref. and as the ingredient B, alcohols, (di)mercaptans, glycols, or the like, are pref. In addition, when (di)mercaptans are used as the ingredient B, the aimed polymer obtd. is a new polymer.