Polycarbonate boasts excellent mechanical properties, with a high modulus of elasticity, low friction coefficient, and good wear resistance. It also exhibits high resistance to creep and stress relaxation. Polycarbonate has good dimensional stability with minimal water absorption, making its impact on mechanical properties negligible. It has good dielectric properties, with minimal changes in dielectric constant and tangent of loss angle over a wide range of frequencies and temperatures. Its heat resistance is poor, and it tends to decompose releasing phthalic anhydride at molding temperatures, so stabilizers are usually added during granulation. Without stress, polycarbonate can be used short-term at 140°C, with a long-term service temperature of 85°C.Polymethyl methacrylate has poor weather resistance, and its general properties usually degrade after atmospheric aging. However, it boasts excellent chemical stability, particularly against organic solvents, with minimal dimensional changes and reduction in mechanical properties. On the other hand, it has poor resistance to corrosive agents like nitric acid and sulfuric acid.