Abstract: Acomposite of 60% of lanthanum stearate and 40%(mass fraction) of stearic acid was prepared and its influence on the crystallization characteristics of isotatic polypropylene (iPP) was investigated. The results showed that we had found a new kind of β-crystalline form nucleating agent. The composite might induced rather high proportion of β-modification. The relative content of β-phase estimated by WAXDand DSCwas 30% and 51.8% in a PPcontaining 2.5%(mass fraction) of the composite respectively. The isothermal crystallization at 130 ℃ and melting behavior examined by DSCrevealed that the composite accelerated the overall rate of crystallization remarkably. The half crystallization period t _1/2 decreased from 118 min of pure PPto 75 min of PPcontaining 2.5% of the composite. However, the composite had no obvious influence on crystallization mode and the size of α-crystal unit cell.

Key words: Lanthanum stearate compound, Isotatic polypropylene, β-Modification