The fabrication of a polymer and carbon nanostructure composite material is reported. A comprehensive material investigation of this stable dispersed system is presented. The fabrication technique and characterization steps are described where it was found that multiwalled carbon nanotubes and other clearly defined carbon nanostructures were stably dispersed in the polymer matrix. The properties of the material are investigated to characterize the carbon phases present. Experimental measurements of optical limiting of nanosecond laser pulses by a range of these composite materials in solution are reported. These composites were varied according to carbon nanostructure mass content. The experiments were performed using an open aperture z-scan apparatus with 6 ns Gaussian pulses at 532 nm from a frequency-doubled Q-switched Nd:YAG laser. Saturation of the optical limiting was reached at carbon nanostructure mass percentages in excess of 3.8%, relative to the polymer mass. Mechanistic implications of the optical limiting are investigated via angular dependent scattering measurements.