A novel highly efficient β-nucleating agent for polypropylene using nano-CaCO3 as a support

In order to increase the isotactic content of beta-nucleated polypropylene (beta-iPP) and decrease the cost of its production, the investigation and development of novel highly efficient beta-nucleators are important issues. Nano-CaCO3 was used as a support to prepare a supported beta-nucleator, nano-CaCO3-supported calcium pimelate. Fourier transform infrared spectral analysis shows that an in situ chemical reaction takes place between nano-CaCO3 and pimelic acid. Differential scanning calorimetry results indicate that the crystallization and melting temperatures of beta-phase in supported beta-nucleator-nucleated iPP are higher than those of calcium pimelate-nucleated iPP. The beta-nucleating ability of the supported beta-nucleator is little influenced by the cooling rate and crystallization temperature over a wide range. The decreased content of pimelic acid in the supported beta-nucleator slightly decreases the crystallization temperature of iPP but it has no influence on the content of beta-phase in nucleated iPP. A novel supported beta-nucleator has been successfully synthesized via pimelic acid supported on the surface of CaCO3. The crystallization temperature of iPP and melting temperature of beta-phase in iPP nucleated using the supported beta-nucleator are higher than those of iPP nucleated using calcium pimelate. The concept of a supported nucleator will provide a new way to increase the efficiency of polymer additives and to decrease the amounts of them that need to be used by using nanoparticles as supports. (C) 2010 Society of Chemical Industry