Which mechanism limits the strength of thermosetting polymers with extensive cross-linking?

💡 Explanation

When thermosets reach high cross-link density, their stiffness increases, reducing ductility; stress cannot be evenly distributed, resulting in brittle fracture at crack tips because covalent bonds limit chain slip. Therefore brittle fracture occurs, rather than creep, thermal degradation, or hydrolysis, requiring different temperature and environmental factors.

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