A. Plastic raw materials expand by heat, and the coefficient of thermal expansion is much larger than that of metals.
B. The rigidity of general plastic materials is one magnitude lower than that of metals.
C. The mechanical properties of plastic raw materials will decrease significantly under long-term heating.
D. General plastic raw materials will be permanently deformed if they are subjected to a long-term force at room temperature and under a stress lower than their yield strength.
E. Plastic raw materials are extremely sensitive to notch damage.
F. The mechanical properties of plastic raw materials are usually much lower than metals, but some composite materials have higher specific strength and specific modulus than metals. If the product design is reasonable, it will be more advantageous.
G. Generally, the mechanical properties of reinforced plastic raw materials are anisotropic.
H. Some plastic materials will absorb moisture and cause size and performance changes.
I. Some plastics are combustible.
J. The fatigue data of plastic raw materials is still scarce, and it needs to be considered according to the requirements of use.