Structure and Properties of Inflation Films of β-Phase Nucleating Agent-Added Polypropylene

Abstract To a homo-isotactic polypropylene (PP) was added 0 to 10 ppm of quinacridonequinone which was a β-phase nucleating agent for PP. The structure and properties have been studied on the inflation films processed from the PPs by the water-cooling or air-cooling methods. The effect of cooling conditions on crystallization has been also studied for reference. Even PPs containing β-phase nucleating agent do not form the β-phase but the smectic or α-phase at low cooling temperature. However, compared with PP without β-phase nucleating agent, they form the α-phase at lower cooling temperature and form the β-phase at high cooling temperature. Even PPs containing β-phase nucleating agent form only the smectic phase in the water-cooled inflation films but form the β-phase in the air-cooled inflation films if β-phase nucleating agent contents are high. Although the film properties are generally not so much affected by the addition of the β-phase nucleating agent, the dart impact strength increases for the air-cooled films which contain the β-phase.