Modyfication of the Rigid Polyurethane-Polyisocyanurate Foams

Table 1

Temperatures of cleavage of chemical bonds occurring in PUR-PIR foams.

No.	Bond	Temperature of cleavage (°C)
1	Urethane	200.0
2	Ester	260.0
3	Ether	350.0
4	Allophanate	106.0
5	Urea	250.0
6	Biuret	140.0
7	Carbodiimide	240.0
8	Isocyanurate	300.0