Preparation and properties of high vinyl polybutadiene/sepiolite nanocomposites using a sepiolite immobilized Mo-based catalyst

The preparation of polymer/nanoclay nanocomposite has received much attention in recent years from both academic researchers and industry. The addition of nanoclay in polymer matrix could prepare material with improved performance and reduced cost. However, nanocaly is easy to agglomerate resulting in poor dispersion in the matrix. In this work, we proposed the immobilized catalyst prepared by coordination between molybdenum pentachloride (MoCl5) and hydroxyl groups on the nano sepiolite. The obtained sepiolite immobilized catalyst was used for the in situ polymerization of butadiene. The butadiene monomers were diffused into the tiny holes and channels of the sepiolite and sepiolite dispersed uniformly by the effect of in situ polymerization. The immobilization of sepiolite improves the dispersity of MoCl5 during polymerization and further enhances the activity of the catalyst. The coordination between sepiolite and MoCl5 results in a slight drop in vinyl content, and the molecular weight distribution remain unchanged. The flame retardant property of the nanocomposite was further investigated, and the result shows that the addition of sepiolite could increase the Oxygen index. This novel composite with well-dispersed sepiolite and high content of vinyl can be further applied to flame-retardant elastic materials.