In the present work

the crystalline morphology of polypropylene/high density polyethylene (PP/HDPE) was observed by the method of polarized light micrography(PLM)

and the melting behaviour was in vestigated by differential scanning calorimetry. It has been shown that the incorporation of HOPE resulted in decreasing the regularity degree of PP spherulites and forming some defection in the crystalline region. It was also found that Y-irradiation strongly affected the crystallinity of PP/HDPE blends. The melting point and crystallinity of PP and/or HDPE in the blends decreased with radiation dose. The crystallinity of pure PP wasn't noticeable changed and that of pure HDPE increased with radiation dose. The more the blends contained HDPE

the faster the melting point and crystallinity of PP decreased

but pure PP showed a relatively faster decreased in themelting point than in the PP/HDPE blends. The results mighat radiation induced chain scission mainly took place in PP crystalline regions

especially in the imperfect regions.