Crystallization of nanocomposites of an isotactic random butene-1/ethylene copolymer and layered double hydroxide

Abstract

The effect of the presence of a layered double hydroxide (LDH) nanofiller on the crystallization behavior of a random isotactic butene-1/ethylene copolymer was investigated. Addition of LDH enhanced heterogeneous nucleation of the ordering process of the polymer matrix leading to an increase of the temperature of formation of the Form II mesophase on cooling the melt. Consequently, the size of spherulites of the polymer matrix was markedly reduced in the nanocomposites. In contrast, the Form II mesophase–Form I crystal phase transition kinetics and the final crystallinity were not affected by the presence of LDH. Addition of the LDH nanofiller led to a beneficial increase of the stiffness which suggests a route for compensating of the lower stiffness of the random copolymer compared to the homopolymer. Random copolymerization accelerates the disadvantageous room-temperature mesophase–crystal transition, but results in a reduction of the crystallinity. The addition of LDH counterbalances the lowering of the crystal fraction.