Buckyball polymers

This one has me a little bit puzzled in a number of ways. A paper at the physics arxiv discusses the polymerization of buckyballs (fullerenes)using 1,2,4-trimethyl benzene (TMB) as a comonomer. The resulting polymer then was an alternating copolymer.

From page 9:"However, the solubility of the material was found to change with time. Unlike raw C₆₀ powder, well known to be highly soluble in aromatic solvents, the as-made nanowires were only partially soluble in these solvents, and this solubility decreased further with time." This is doubly puzzling, not only because of the change over time in solubility, but also because I would expect the TMB to have only a minor change on the over interactions between solute and solvent. There are 60/9 more carbon-solvent interactions with the buckyballs than with the bridge.

All of the easy explanations are not available: "We noted that the resulting nanowires were highly stable, as indicated by the fact that there was no detectable alteration in either their crystalline morphology, crystal color, or sample weight as a function of time." It's problem that will have to wait for someone else to solve.