Effect of polyacrylic salt nucleating agents on the properties of isotactic polypropylene

A series of polyacrylic salts are used as nucleating agents in isotactic polypropylene (iPP). Investigations are done on the mechanical characteristics, crystallization behavior, and melting behavior of nucleated iPP. According to the result from differential scanning calorimetry (DSC), the temperature at which nucleated iPP crystallize was 3–5 °C higher than the temperature at which pure iPP. Meanwhile, zinc polyacrylate, potassium polyacrylate, and sodium polyacrylate have the ability to induce β-crystals in iPP, according to wide-angle X-ray diffraction data. The optical microscope observation combined with DSC results shows that potassium polyacrylate had a β-nucleation effect when it had a lamellar crystal structure. When compared to pure iPP, the impact strength of iPP nucleated with sodium polyacrylate or potassium polyacrylate is improved by 23.48% and 24.35%, respectively. According to the mechanical properties results, there is no significant change in the tensile strength and flexural modulus of nucleated iPP with sodium polyacrylate and potassium polyacrylate. Without compromising its stiffness, sodium polyacrylate or potassium polyacrylate can increase the toughness of nucleated iPP.