The vacuum of space does not expand that is totally impossible as nothing was there before the universe existed. It has no boundaries.
Matter was born into a a total vacuum where nothing ever existed before. Matter should always be observed as a community of living particles of atoms and its they that have created every thing we can see or know by our senses exist and should start to understand was by intelligent design of which was created by our atom builders. We as a intelligent species are slaves of the atoms for specific logical reason I have explained that reason in my book Atoms talking to me .
When we look at how could the universe we must think what actually logically happened that it was created into a vacuum and it forced its expanse with a massive explosion to create in increasing distance with in a vacuum with actually nothing before in it. Within those distance its giving birth within groups of spheres we call Galaxies new sphere creating new atoms it looks like its never going to stop creating it self it even has crematory like finial destination places we call black holes to rid non active masses of atoms at the end of a stars useful atomic fusions life. after a super Nova that creates more distance between groups of atom sphere communities of atoms.
The universe in my logic opinion at this stage of my research is not dying its growing by creating more and more distance in a vacuum of nothingness. It shows amazing intelligent design. That I have began to understand and hope others will start to also.