A novel silica-based nucleating agent for polypropylene: Preparation, characterization, and application
Journal of Vinyl & Additive Technology, 2018, 24(1): 58-67.
Inorganic silica is widely used as nucleating agents for isotactic polypropylene (iPP), and to achieve a better effect, the amount of addition is generally higher than 5 wt%. A novel silica-based nucleating agent (SPKSol) was prepared by two steps: aromatic phosphate (MDBP-POOH) was first supported on the silica sol via chemical reaction with -aminopropyltrimethylsilane (KH550) as the linker, and the obtained product (PKSol) was further processed by spray-drying. Fourier-transform infrared spectrometry and thermogravimetric analysis confirmed the incorporation of MDBP-POOH on the silica sol. The results demonstrated a spherical particle with an average size of 5 m, and a slit-shaped pore structure was formed from the originally formed nano-sized particles of PKSol after the spray-drying process. Transmission electron microscopy showed that the SPKSol was well-dispersed in the iPP matrix. Incorporating a very small amount of SPKSol (0.2 wt%) can effectively increase the crystallization temperature and improve the mechanical properties of polypropylene. In addition, the addition of SPKSol could even shift the haze of polypropylene to a lower value, obviously lower than that with PKSol as the nucleating agent. The preparation, characterization of SPKSol, and their application in iPP composites were explored in detail. J. VINYL ADDIT. TECHNOL., 24:58-67, 2018.