Preparation study of PU Nanocomposites via two different Methods

Thermoplastic polyurethanes Elastomer (TPUE) are high performance elastomers with applications as coating, fibers, films, footwear, wire and flexible tubing [1]. TPUEs are multi-phase segmented polymers that exhibit a two-phase microstructure, which arises from the incompatibility between the soft and the hard segments [2]. Resulting from their specific micro-phase structure, polyurethane elastomers offer very good elasticity with reasonably high mechanical strength and abrasion resistance at the same time, and also controllable hardness. Unfortunately, there are two inhibiting factors for applicability of some polyurethane: their limited stability at temperatures above 90 ºC, and their flammability [3]. One of the important methods for improvement of thermal properties of polyurethane elastomers involved the incorporation of inorganic particles such as nanoclay to PU matrix. When this route leads to nanocomposite structure, the product exhibits remarkable improvements in mechanical, thermal and barrier properties. This improvement in properties is attributed to the strong interfacial interaction between the matrix and layered silicate of clay, changes in polymer molecular dynamic and crystallinity. Some works have been carried out to study of nanoclay content effect, morphology, properties and interactions between clay and isocyanate group in PU nanocomposite [4-5].In this work, polyurethane nanocomposites were prepared via two different processes of in situ polymerization and melt intercalation. Polyurethane, nanoclay type and quantity were kept constant, to investigate the effect of preparation process. The physical and mechanical properties of prepared polyurethane nanocomposites were measured and reported.