Polymers pyrolisys - how it works?

Gloyn

Hi,

I was browsing the Internet and I found a thread about polymers pyrolysis:

http://www.energeticforum.com/renewa...l-cheaply.html

Guy there states, that just due to temperature of about 400C polymer chains are being broken into shorter chains and he obtains hydrocarbons from diesel fuel range (10-15 carbons in chain). My question is: how is that possible, as all papers that I've read until now states, that not only high temperature is required, but also pressure of ~12MPa at least for successful decomposition of polymers. What chemical reactions are involved? It would be awesome if someone could give a short description of what happens (from a point of view of a chemist) to those polymers in the device from the link.