Effect of Metallic Salts of Glutaric Acid on the Formation of β-crystalline Form in Isotactic Polypropylene

The effects of glutaric acid and the lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, and cadmium salts of glutaric acid on the formation of beta-crystalline form in isotactic polypropylene (iPP) at the crystallization temperatures 120 and 130 degrees C have been investigated. It is found that glutaric acid and the sodium, potassium, and zinc salts of glutaric acid inhibit the formation of beta-crystalline form in polypropylene. Lithium glutarate has a limited positive effect on the formation of beta-crystalline form. Magnesium, calcium, strontium, barium salts of glutaric acid exhibit increased beta-nucleation abilities with the increasing atomic radii of the combined metals. Cadmium glutarate is a good beta-nucleating agent and the formation of beta-crystalline form is favored at the crystallization temperature of 120 degrees C. The increases in the orientation of b-axes of the nucleated iPP samples are due to the presences of sodium and zinc salts of glutaric acid.