Polyethylene/Palygorskite Nano-Composite Prepared Via In-Situ Coordinated Polymerization Approach: Structure And Property

A novel methodology for the preparation of polyethylene/palygorskite nano-composites, "in-situ coordinated polymerization" was proposed. Ziegler-Natta catalyst was first supported on the surface of nano-scale crystal fibers of palygorskite, subsequently initiates ethylene polymerization on the surface of the fibers. The palygorskite was encapsulated by polyethylene and becomes reinforcement fibers of the composite. The palygorskite fibers should be thermal-treated to remove water, to ensure the supported titanium species possess proper activity for the polymerization of ethylene. The effect of the conditions of thermal treatment, titanium supporting and other factors such as temperature, type of co-catalyst on the initiation activity of the palygorskite fibers are investigated in this paper. The resulted organic/inorganic nano-composites exhibit many interesting properties. Compared with Polyethylene/Palygorskite composites prepared via melt blending, polyethylene/palygorskite nano-Composite prepared via in situ coordinated polymerization approach has stronger crystallization ability and high mechanical properties. The relationships among the preparation method, structure and properties of the obtained nano-composite were investigated. It was found that the fibers of palygorskite were uniformly dispersed in the polyethylene matrix and there are strong interaction between the fibers and the matrix, which constituted the key factor for the improved mechanical properties. Some gel was detected in the composites, which was attributed to the formation of "comb-like" structure of polyethylene chains on the palygorskite fibers.