bPUR	biopolyurethane
CBA	chemical blowing agent
CFC	chlorofluorocarbon
DE	diethyl ether
EP	epoxy
FA	furfuryl alcohol
HCFC	hydrochlorofluorocarbon
HFC	hydrofluorocarbon
MBF	mechanically blown foam
MDI	methylene diphenyl diisocyanate
mMDI	pure monomeric MDI
PBA	physical blowing agent
PF	phenol–formaldehyde
PFC	perfluorocarbon
PIR	polyisocyanurate
pMDI	polymeric MDI
PUA	polyurea
PUR	polyurethane
TDI	toluene diisocyanate
TFF	tannin–furanic foams
θ	tortuosity
k	permeability
ρ	relative density
ρa	apparent density
ρs	skeletal density (i.e., of the solid fraction)
ϕ	porosity