In some thermoplastics, the crack-formation process may be preceded by crazing.

• A. Not sure
• B. Only in crosslinked polymers
• C. True
• D. False

Answer: (C)

Crazing is a damage mode in many thermoplastics where tensile stress creates microvoids that are bridged by thin polymer fibrils, forming a network called a craze. This craze can carry load and absorb energy, but as it grows and connects with other crazes, it creates a path of weakness that can evolve into a crack. Because crazing can occur in some thermoplastics before a crack actually forms, the crack-formation process may indeed be preceded by crazing. Crosslinked polymers tend to resist crazing due to restricted chain mobility, which is why this behavior isn’t universal across all polymers.