β‐Crystallization and mechanical properties of aluminum hydroxide‐filled polypropylene composites

In order to provide aluminum hydroxide with β‐nucleating surface (β‐ATH) for PP crystallization, the calcium pimelate supported on the surface of ATH was prepared through chemical reaction between calcified ATH and pimelic acid in our lab. The β‐ATH particles were characterized by Fourier transform infrared spectrometry, X‐ray photoelectron spectroscopy and scanning electron microscopy. Effect of ATH, calcified ATH, and β‐ATH on crystallization and crystalline modification of PP was investigated by differential scanning calorimetry. The results indicated that the prepared β‐ATH has higher heterogeneous nucleation than ATH and calcified ATH for PP crystallization. Addition of ATH and calcified ATH has no influence on the crystalline modification of PP. The β‐ATH can induce the formation of β‐crystal in the ATH‐filled PP composites with β‐crystal content of above 90%. The transformation of surface nucleation mechanism of ATH from α‐nucleation into β‐nucleation was investigated. The effects of β‐ATH content, mass ratio of calcified ATH/pimelic acid and concentration of calcium acetate solution in the preparation of calcified ATH on the heterogeneous nucleation and β‐crystal content of β‐ATH‐filled PP composites were discussed. The mechanical performance of the prepared β‐ATH‐filled PP composites were also characterized. POLYM. COMPOS., 40:E194–E201, 2019. © 2017 Society of Plastics Engineers