Crystallization in blends of isotactic polypropylene with polyethylene-b-poly(ethylene-co-butylene)-b-polyethylene block copolymer

In this study, isothermal crystallization in blends of isotactic polypropyl ene (i-PP) with polyethylene-b-poly(ethylene-co-butylene)-b-polyethylene bl ock copolymer (CEBC) was investigated using a polarized photometer, polariz ed microscope and differential scanning calorimeter. Half time of crystalli zaiton (tau(1/2)) is increasing with increasing CEBC content in i-PP/CEBC b lends. Avrami index and rate constant of crystal growth decrease with incre asing CEBC content in i-PP/CEBC blends. On the contrary, heat of fusion of i-PP crystal in the blends is almost constant against the variation of CEBC content in i-PP/CEBC blends. Hence, it is pointed out that blending i-PP w ith CEBC caused only retardation of rate of crystalline growth and change i n mechanism of crystalline growth from three dimensional to two dimensional growth.