Abstract: The crystallization behaviors and thermal and mechanical properties of neat and β-nucleated polypropylene (PP) and propylene/ethylene random copolymer (PPR) were comparatively investigated. The experimental results indicated that the melting points and crystallization points of PP and PPR increased with decreasing ethylene content. Low ethylene content led to high β crystalline form. The heat distortion temperature and impact properties of PPRs were greatly improved with increasing β-form crystallites. The lab-made β-nucleator of polypropylene attributed to a high proportion of β-form in PPRs, higher than 80 %.

Key words: propylene-ethylene random copolymer, β-nucleator, crystallization behavior, heat distortion temperature, mechanical property