Nano-composites derived from melt mixing a thermotropic liquid crystalline polyester and zinc sulfonated polystyrene ionomers

A nano-composite was produced by simply melt mixing a blend of a thermotropic liquid crystalline polyester (LCP) and the zinc salt of a lightly sulfonated polystyrene ionomer at 300 °C. The nano-particles, which were in the form of relatively uniform rectangular prisms of ca. 30 nm×30 nm×200 nm, formed from the LCP phase due to an ester-interchange reaction between the LCP and residual catalytic amounts of zinc acetate that were present from the neutralization step in the preparation of the ionomer. The nano-particles possessed a different crystal pattern and higher melting point than the parent LCP, and they were easily oriented when the blend melt was uniaxially stretched. The nano-particles provided reinforcement of the ionomer comparable to what would be expected of short fibers with a modulus of at least 25 GPa.