The long-term service temperature of general polymeric adhesives is typically below 200°C. However, in some special applications of materials, the long-term service temperature is required to exceed 200°C. For example, adhesives used in microelectronic components need to bond with substrates at 400°C in an inert atmosphere; structural adhesives for supersonic aircraft must withstand 230°C for tens of thousands of hours; adhesives used in missiles are required to maintain mechanical properties at 540°C for more than 1 minute. These all belong to special-purpose adhesives for specific applications