Hi Luiz,
I bought small sheets (0.5 m x 0.5 m) of stiff polyurethane foam 4 to 6 mm thick from internet contacts in the USA. It was sent by UPS to me ok. No large-scale "shipping".

Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison