The morphology of graft copolymers and blends of cis-1

4-polybutadiene and trans-1

4-polybutadiene was studied by electron microscopy

electron diffraction and DSC. It is found that at room temperature trans-1

4-polybutadiene lamellae disperse in amorphous cis-1

4-polybutadiene matrix

while at low temperature in crystalline cis-1

4-polybutadiene spherulites. This paper discussed the effect of trans-1

4-polybudiene content on microphase separation: shperulite structure at low temperature and on tensile pro-perties of the copolymers.