An aerospace engineering company is selecting a polymer to fabricate a rigid housing for a high-temperature actuator designed to operate at 250∘C250^\circ\text{C}250∘C. They require a material that will maintain its shape and rigidity under thermal stress without melting or undergoing plastic deformation.
Which statement correctly explains the behavior and suitability of the chosen polymer type based on its structure and bonding?
The cross-linked polymer will undergo reversible deformation at 250∘C250^\circ\text{C}250∘C because high thermal energy allows the covalent cross-links to rapidly break and reform, allowing the material to flow and then reset upon cooling.
The linear thermoplastic polymer will maintain its rigidity at 250∘C250^\circ\text{C}250∘C because the close alignment of the chains enables the formation of strong ionic networks that require more energy to break than covalent bonds.
The cross-linked polymer will remain rigid and decompose rather than melt at high temperatures because the strong covalent cross-links restrict chain movement and prevent them from sliding past one another.
The linear thermoplastic polymer is more suitable for high-temperature rigidity because its weak intermolecular forces allow the polymer chains to easily slide past each other, absorbing thermal energy without structural failure.