Quoted from "Mortvana"
Yup, but there that's because of oposite charge. And because of that, you can't assemble these into a bigger one (that was what he was suggesting). At least you could assemble Neutron + Neutron, but that wouldn't be created something bigger, as they wouldn't be especially attracted one by the other (so that wouldn't make any nucleus, just 2 Neutrons closer than before )
I don't know quantum physics very much so don't believe everything I say. However I think the antimatter-matter-annhilation is not becuase they're opposite charge, otherwise hydrogen will spontaneously explode in a vacuum. And things called antineutrons, antineutrinos exist too, and they do explode when they meet neutrons and neutrinos respectively.
Plus isn't a di-neutron supposed to be unstable?