Relationship between molecular structure and nucleation of benzylidene acetals in isotactic polypropylene

Abstract Relationship between molecular structure and nucleation of benzylidene acetals in isotactic polypropylene was investigated by differential scanning calorimeter and two‐dimensional correlative infrared spectra. The results indicated that benzylidene acetals can dissolve into isotactic polypropylene at high temperature and form nuclei to induce the crystallization of isotactic polypropylene at low temperature. The solubility of benzylidene acetals depend on the number of hydroxyl, but the nucleation of benzylidene acetals depend on the number of benzylidene, which could interact with methyl of isotactic polypropylene. The latter intermolecular interaction makes the infrared absorbance of methyl change before that of skeleton C‐C and methine of isotactic polypropylene in the induction period of crystallization. The order is opposite in the induction period of crystallization of virgin isotactic polypropylene. Then, new efficient nucleating agents for isotactic polypropylene can be designed by changing the number of hydroxyl and benzylidene of benzylidene acetals. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers