A polyacetal (POM)/poly(epsilon-caprolactone) (PCL) reactive blend prepared via a chain-transfer reaction was investigated with respect to its morphology and non-isothermal crystallization, and the results were compared with those of a simple POM/PCL blend. The reactive blend had a microscopically phase-separated morphology in which the diameter of the PCL microphase was below 100 nm, and it clearly yielded ring-banded spherulites, whereas between the two blends, there were no significant differences in the diameters and polygonal edges of the spherulites and in the long period of the POM phases. The PCL part of the reactive blend crystallized within the confined microspace with about 10%, lower crystallinity than that of the corresponding simple blend. A lower Avrami exponent and crystallization rate parameter of the PCL part were observed in the primary crystallization process of the reactive blend. In contrast, the crystallinity of the POM component and the nonisothermal crystallization kinetic parameters of the POM part showed no noticeable differences between the two blends at any given cooling rate. (C) 2007 Wiley Periodicals, Inc.