Kevlar - Styrofoam material, where to get more

I second the idea that unless you specifically need Kevlar face
sheets, it is overkill and a totally needless expense. It is
relatively easy to make your own but if you want commercially
available stuff the two largest commercial suppliers a

http://www.bellcomb.com/
and . . .
http://www.panelteccorp.com/

Note that if you mention that you got their contact information from
an aviation-related source they will hang up on you immediately. If
you are doing anything OTHER than aviation they will talk to you just
fine.

Both companies can probably ID the product from the photos you have,
but again--unless you have a specific spec for Kevlar, fiberglass is
much cheaper and infinitely easier to work with. The core choice is
driven by what the panel will be exposed to in terms of temp,
chemicals, and the required thickness. There are a few major families
of foam, each with good but differing properties. There is also
honeycomb of various types, which are suited to particular situations
but require a little extra work and ideally should have glue sheet
between the face sheets and the core. Take-home message--stick with
foam if you can. In our own project we recently switched away from
honeycomb cores and went back to Divinycell. Counter-intuitively,
this saved both money and weight.